An automatically generated list of publications should appear below. If not, the same list can be accessed on the arXiv.

Stephen Feeney's articles on arXiv

[1]  http://arxiv.org/abs/2212.04521v2 [ html pdf ]
A simulation-based inference pipeline for cosmic shear with the Kilo-Degree Survey
Kiyam Lin, Maximilian von Wietersheim-Kramsta, Benjamin Joachimi, Stephen Feeney

The standard approach to inference from cosmic large-scale structure data employs summary statistics that are compared to analytic models in a Gaussian likelihood with pre-computed covariance. To overcome the idealising assumptions about the form of the likelihood and the complexity of the data inherent to the standard approach, we investigate simulation-based inference (SBI), which learns the likelihood as a probability density parameterised by a neural network. We construct suites of simulated, exactly Gaussian-distributed data vectors for the most recent Kilo-Degree Survey (KiDS) weak gravitational lensing analysis and demonstrate that SBI recovers the full 12-dimensional KiDS posterior distribution with just under $10^4$ simulations. We optimise the simulation strategy by initially covering the parameter space by a hypercube, followed by batches of actively learnt additional points. The data compression in our SBI implementation is robust to suboptimal choices of fiducial parameter values and of data covariance. Together with a fast simulator, SBI is therefore a competitive and more versatile alternative to standard inference.

[2]  http://arxiv.org/abs/2012.06593v4 [ html pdf ]
Prospects for Measuring the Hubble Constant with Neutron-Star-Black-Hole Mergers
Stephen M. Feeney, Hiranya V. Peiris, Samaya M. Nissanke, Daniel J. Mortlock

Gravitational wave (GW) and electromagnetic (EM) observations of neutron-star-black-hole (NSBH) mergers can provide precise local measurements of the Hubble constant ($H_0$), ideal for resolving the current $H_0$ tension. We perform end-to-end analyses of realistic populations of simulated NSBHs, incorporating both GW and EM selection for the first time. We show that NSBHs could achieve unbiased 1.5-2.4% precision $H_0$ estimates by 2030. The achievable precision is strongly affected by the details of spin precession and tidal disruption, highlighting the need for improved modeling of NSBH mergers.

[3]  http://arxiv.org/abs/2104.02728v1 [ html pdf ]
Unbiased likelihood-free inference of the Hubble constant from light standard sirens
Francesca Gerardi, Stephen M. Feeney, Justin Alsing

Multi-messenger observations of binary neutron star mergers offer a promising path towards resolution of the Hubble constant ($H_0$) tension, provided their constraints are shown to be free from systematics such as the Malmquist bias. In the traditional Bayesian framework, accounting for selection effects in the likelihood requires calculation of the expected number (or fraction) of detections as a function of the parameters describing the population and cosmology; a potentially costly and/or inaccurate process. This calculation can, however, be bypassed completely by performing the inference in a framework in which the likelihood is never explicitly calculated, but instead fit using forward simulations of the data, which naturally include the selection. This is Likelihood-Free Inference (LFI). Here, we use density-estimation LFI, coupled to neural-network-based data compression, to infer $H_0$ from mock catalogues of binary neutron star mergers, given noisy redshift, distance and peculiar velocity estimates for each object. We demonstrate that LFI yields statistically unbiased estimates of $H_0$ in the presence of selection effects, with precision matching that of sampling the full Bayesian hierarchical model. Marginalizing over the bias increases the $H_0$ uncertainty by only $6\%$ for training sets consisting of $O(10^4)$ populations. The resulting LFI framework is applicable to population-level inference problems with selection effects across astrophysics.

[4]  http://arxiv.org/abs/1912.09498v2 [ html pdf ]
SSSpaNG! Stellar Spectra as Sparse, data-driven, Non-Gaussian processes
Stephen M. Feeney, Benjamin D. Wandelt, Melissa K. Ness

Upcoming million-star spectroscopic surveys have the potential to revolutionize our view of the formation and chemical evolution of the Milky Way. Realizing this potential requires automated approaches to optimize estimates of stellar properties, such as chemical element abundances, from the spectra. The volume and quality of the observations strongly motivate that these approaches should be data-driven. With this in mind, we introduce SSSpaNG: a data-driven non-Gaussian Process model of stellar spectra. We demonstrate the capabilities of SSSpaNG using a sample of APOGEE red clump stars, whose model parameters we infer via Gibbs sampling. Pooling information between stars to infer their covariance, we permit clear identification of the correlations between spectral pixels. Harnessing these correlations, we infer the true spectrum of each star, inpainting missing regions and denoising by a factor of at least 2 for stars with signal-to-noise of ~20. As we marginalize over the covariance matrix of the spectra, the effective prior on these true spectra is non-Gaussian and sparsifying, favouring typically small but occasionally large excursions from the mean. The high-fidelity inferred spectra produced will enable improved elemental abundance measurements for individual stars. Our model also allows us to quantify the information gained by observing portions of a star's spectrum, and thereby define the most mutually informative spectral regions. Using 25 windows centred on elemental absorption lines, we demonstrate that the iron-peak and alpha-process elements are particularly mutually informative for these spectra, and that the majority of information about a target window is contained in the 10-or-so most informative windows. Such mutual-information estimates have the potential to inform models of nucleosynthetic yields and the design of future observations.

[5]  http://arxiv.org/abs/2010.02877v1 [ html pdf ]
Exploiting Network Topology for Accelerated Bayesian Inference of Grain Surface Reaction Networks
Johannes Heyl, Serena Viti, Jonathan Holdship, Stephen M. Feeney

In the study of grain-surface chemistry in the interstellar medium, there exists much uncertainty regarding the reaction mechanisms with few constraints on the abundances of grain-surface molecules. Bayesian inference can be performed to determine the likely reaction rates. In this work, we consider methods for reducing the computational expense of performing Bayesian inference on a reaction network by looking at the geometry of the network. Two methods of exploiting the topology of the reaction network are presented. One involves reducing a reaction network to just the reaction chains with constraints on them. After this, new constraints are added to the reaction network and it is shown that one can separate this new reaction network into sub-networks. The fact that networks can be separated into sub-networks is particularly important for the reaction networks of interstellar complex organic molecules, whose surface reaction networks may have hundreds of reactions. Both methods allow the maximum-posterior reaction rate to be recovered with minimal bias.

[6]  http://arxiv.org/abs/1811.11723v3 [ html pdf ]
Unbiased Hubble constant estimation from binary neutron star mergers
Daniel J. Mortlock, Stephen M. Feeney, Hiranya V. Peiris, Andrew R. Williamson, Samaya M. Nissanke

Gravitational wave (GW) observations of binary neutron star (BNS) mergers can be used to measure luminosity distances and hence, when coupled with estimates for the mergers' host redshifts, infer the Hubble constant, $H_0$. These observations are, however, affected by GW measurement noise, uncertainties in host redshifts and peculiar velocities, and are potentially biased by selection effects and the mis-specification of the cosmological model or the BNS population. The estimation of $H_0$ from samples of BNS mergers with optical counterparts is tested here by using a phenomenological model for the GW strains that captures both the data-driven event selection and the distance-inclination degeneracy, while being simple enough to facilitate large numbers of simulations. A rigorous Bayesian approach to analyzing the data from such simulated BNS merger samples is shown to yield results that are unbiased, have the appropriate uncertainties, and are robust to model mis-specification. Applying such methods to a sample of $N \simeq 50$ BNS merger events, as LIGO+Virgo could produce in the next $\sim 5$ years, should yield robust and accurate Hubble constant estimates that are precise to a level of $\sim 2$ km s$^{-1}$ Mpc$^{-1}$, sufficient to reliably resolve the current tension between local and cosmological measurements of $H_0$.

[7]  http://arxiv.org/abs/1908.07495v1 [ html pdf ]
PICO: Probe of Inflation and Cosmic Origins
S. Hanany, M. Alvarez, E. Artis, P. Ashton, J. Aumont, R. Aurlien, R. Banerji, R. B. Barreiro, J. G. Bartlett, S. Basak, N. Battaglia, J. Bock, K. K. Boddy, M. Bonato, J. Borrill, F. Bouchet, F. Boulanger, B. Burkhart, J. Chluba, D. Chuss, S. Clark, J. Cooperrider, B. P. Crill, G. De Zotti, J. Delabrouille, E. Di Valentino, J. Didier, O. Dore, H. K. Eriksen, J. Errard, T. Essinger-Hileman, S. Feeney, J. Filippini, L. Fissel, R. Flauger, U. Fuskeland, V. Gluscevic, K. M. Gorski, D. Green, B. Hensley, D. Herranz, J. C. Hill, E. Hivon, R. Hlozek, J. Hubmayr, B. R. Johnson, W. Jones, T. Jones, L. Knox, A. Kogut, M. Lopez-Caniego, C. Lawrence, A. Lazarian, Z. Li, M. Madhavacheril, J. B. Melin, J. Meyers, C. Murray, M. Negrello, G. Novak, R. O'Brient, C. Paine, T. Pearson, L. Pogosian, C. Pryke, G. Puglisi, M. Remazeilles, G. Rocha, M. Schmittfull, D. Scott, P. Shirron, I. Stephens, B. Sutin, M. Tomasi, A. Trangsrud, A. van Engelen, F. Vansyngel, I. K. Wehus, Q. Wen, S. Xu, K. Young, A. Zonca

The Probe of Inflation and Cosmic Origins (PICO) is a proposed probe-scale space mission consisting of an imaging polarimeter operating in frequency bands between 20 and 800 GHz. We describe the science achievable by PICO, which has sensitivity equivalent to more than 3300 Planck missions, the technical implementation, the schedule and cost.

[8]  http://arxiv.org/abs/1904.05364v2 [ html pdf ]
Cosmic Shear: Inference from Forward Models
Peter L. Taylor, Thomas D. Kitching, Justin Alsing, Benjamin D. Wandelt, Stephen M. Feeney, Jason D. McEwen

Density-estimation likelihood-free inference (DELFI) has recently been proposed as an efficient method for simulation-based cosmological parameter inference. Compared to the standard likelihood-based Markov Chain Monte Carlo (MCMC) approach, DELFI has several advantages: it is highly parallelizable, there is no need to assume a possibly incorrect functional form for the likelihood and complicated effects (e.g the mask and detector systematics) are easier to handle with forward models. In light of this, we present two DELFI pipelines to perform weak lensing parameter inference with lognormal realizations of the tomographic shear field -- using the C_l summary statistic. The first pipeline accounts for the non-Gaussianities of the shear field, intrinsic alignments and photometric-redshift error. We validate that it is accurate enough for Stage III experiments and estimate that O(1000) simulations are needed to perform inference on Stage IV data. By comparing the second DELFI pipeline, which makes no assumption about the functional form of the likelihood, with the standard MCMC approach, which assumes a Gaussian likelihood, we test the impact of the Gaussian likelihood approximation in the MCMC analysis. We find it has a negligible impact on Stage IV parameter constraints. Our pipeline is a step towards seamlessly propagating all data-processing, instrumental, theoretical and astrophysical systematics through to the final parameter constraints.

[9]  http://arxiv.org/abs/1902.10541v2 [ html pdf ]
PICO: Probe of Inflation and Cosmic Origins
Shaul Hanany, Marcelo Alvarez, Emmanuel Artis, Peter Ashton, Jonathan Aumont, Ragnhild Aurlien, Ranajoy Banerji, R. Belen Barreiro, James G. Bartlett, Soumen Basak, Nick Battaglia, Jamie Bock, Kimberly K. Boddy, Matteo Bonato, Julian Borrill, François Bouchet, François Boulanger, Blakesley Burkhart, Jens Chluba, David Chuss, Susan E. Clark, Joelle Cooperrider, Brendan P. Crill, Gianfranco De Zotti, Jacques Delabrouille, Eleonora Di Valentino, Joy Didier, Olivier Doré, Hans K. Eriksen, Josquin Errard, Tom Essinger-Hileman, Stephen Feeney, Jeffrey Filippini, Laura Fissel, Raphael Flauger, Unni Fuskeland, Vera Gluscevic, Krzysztof M. Gorski, Dan Green, Brandon Hensley, Diego Herranz, J. Colin Hill, Eric Hivon, Renée Hložek, Johannes Hubmayr, Bradley R. Johnson, William Jones, Terry Jones, Lloyd Knox, Al Kogut, Marcos López-Caniego, Charles Lawrence, Alex Lazarian, Zack Li, Mathew Madhavacheril, Jean-Baptiste Melin, Joel Meyers, Calum Murray, Mattia Negrello, Giles Novak, Roger O'Brient, Christopher Paine, Tim Pearson, Levon Pogosian, Clem Pryke, Giuseppe Puglisi, Mathieu Remazeilles, Graca Rocha, Marcel Schmittfull, Douglas Scott, Peter Shirron, Ian Stephens, Brian Sutin, Maurizio Tomasi, Amy Trangsrud, Alexander van Engelen, Flavien Vansyngel, Ingunn K. Wehus, Qi Wen, Siyao Xu, Karl Young, Andrea Zonca

The Probe of Inflation and Cosmic Origins (PICO) is an imaging polarimeter that will scan the sky for 5 years in 21 frequency bands spread between 21 and 799 GHz. It will produce full-sky surveys of intensity and polarization with a final combined-map noise level of 0.87 $\mu$K arcmin for the required specifications, equivalent to 3300 Planck missions, and with our current best-estimate would have a noise level of 0.61 $\mu$K arcmin (6400 Planck missions). PICO will either determine the energy scale of inflation by detecting the tensor to scalar ratio at a level $r=5\times 10^{-4}~(5\sigma)$, or will rule out with more than $5\sigma$ all inflation models for which the characteristic scale in the potential is the Planck scale. With LSST's data it could rule out all models of slow-roll inflation. PICO will detect the sum of neutrino masses at $>4\sigma$, constrain the effective number of light particle species with $\Delta N_{\rm eff}<0.06~(2\sigma)$, and elucidate processes affecting the evolution of cosmic structures by measuring the optical depth to reionization with errors limited by cosmic variance and by constraining the evolution of the amplitude of linear fluctuations $\sigma_{8}(z)$ with sub-percent accuracy. Cross-correlating PICO's map of the thermal Sunyaev-Zeldovich effect with LSST's gold sample of galaxies will precisely trace the evolution of thermal pressure with $z$. PICO's maps of the Milky Way will be used to determine the make up of galactic dust and the role of magnetic fields in star formation efficiency. With 21 full sky legacy maps in intensity and polarization, which cannot be obtained in any other way, the mission will enrich many areas of astrophysics. PICO is the only single-platform instrument with the combination of sensitivity, angular resolution, frequency bands, and control of systematic effects that can deliver this compelling, timely, and broad science.

[10]  http://arxiv.org/abs/1903.00007v1 [ html pdf ]
Fast likelihood-free cosmology with neural density estimators and active learning
Justin Alsing, Tom Charnock, Stephen Feeney, Benjamin Wandelt

Likelihood-free inference provides a framework for performing rigorous Bayesian inference using only forward simulations, properly accounting for all physical and observational effects that can be successfully included in the simulations. The key challenge for likelihood-free applications in cosmology, where simulation is typically expensive, is developing methods that can achieve high-fidelity posterior inference with as few simulations as possible. Density-estimation likelihood-free inference (DELFI) methods turn inference into a density estimation task on a set of simulated data-parameter pairs, and give orders of magnitude improvements over traditional Approximate Bayesian Computation approaches to likelihood-free inference. In this paper we use neural density estimators (NDEs) to learn the likelihood function from a set of simulated datasets, with active learning to adaptively acquire simulations in the most relevant regions of parameter space on-the-fly. We demonstrate the approach on a number of cosmological case studies, showing that for typical problems high-fidelity posterior inference can be achieved with just $\mathcal{O}(10^3)$ simulations or fewer. In addition to enabling efficient simulation-based inference, for simple problems where the form of the likelihood is known, DELFI offers a fast alternative to MCMC sampling, giving orders of magnitude speed-up in some cases. Finally, we introduce \textsc{pydelfi} -- a flexible public implementation of DELFI with NDEs and active learning -- available at \url{https://github.com/justinalsing/pydelfi}.

[11]  http://arxiv.org/abs/1802.03404v3 [ html pdf ]
Prospects for resolving the Hubble constant tension with standard sirens
Stephen M. Feeney, Hiranya V. Peiris, Andrew R. Williamson, Samaya M. Nissanke, Daniel J. Mortlock, Justin Alsing, Dan Scolnic

The Hubble constant ($H_0$) estimated from the local Cepheid-supernova (SN) distance ladder is in 3-$\sigma$ tension with the value extrapolated from cosmic microwave background (CMB) data assuming the standard cosmological model. Whether this tension represents new physics or systematic effects is the subject of intense debate. Here, we investigate how new, independent $H_0$ estimates can arbitrate this tension, assessing whether the measurements are consistent with being derived from the same model using the posterior predictive distribution (PPD). We show that, with existing data, the inverse distance ladder formed from BOSS baryon acoustic oscillation measurements and the Pantheon SN sample yields an $H_0$ posterior near-identical to the Planck CMB measurement. The observed local distance ladder value is a very unlikely draw from the resulting PPD. Turning to the future, we find that a sample of $\sim50$ binary neutron star "standard sirens" (detectable within the next decade) will be able to adjudicate between the local and CMB estimates.

[12]  http://arxiv.org/abs/1803.01018v2 [ html pdf ]
The EBEX Balloon Borne Experiment - Detectors and Readout
The EBEX Collaboration, Maximilian Abitbol, Asad M. Aboobaker, Peter Ade, Derek Araujo, François Aubin, Carlo Baccigalupi, Chaoyun Bao, Daniel Chapman, Joy Didier, Matt Dobbs, Stephen M. Feeney, Christopher Geach, Will Grainger, Shaul Hanany, Kyle Helson, Seth Hillbrand, Gene Hilton, Johannes Hubmayr, Kent Irwin, Andrew Jaffe, Bradley Johnson, Terry Jones, Jeff Klein, Andrei Korotkov, Adrian Lee, Lorne Levinson, Michele Limon, Kevin MacDermid, Amber D. Miller, Michael Milligan, Kate Raach, Britt Reichborn-Kjennerud, Carl Reintsema, Ilan Sagiv, Graeme Smecher, Gregory S. Tucker, Benjamin Westbrook, Karl Young, Kyle Zilic

EBEX was a long-duration balloon-borne experiment to measure the polarization of the cosmic microwave background. The experiment had three frequency bands centered at 150, 250, and 410 GHz and was the first to use a kilo-pixel array of transition edge sensor (TES) bolometers aboard a balloon platform; shortly after reaching float we operated 504, 342, and 109 TESs at each of the bands, respectively. We describe the design and characterization of the array and the readout system. We give the distributions of measured thermal conductances, normal resistances, and transition temperatures. With the exception of the thermal conductance at 150 GHz. We measured median low-loop-gain time constants $\tau_{0}=$ 88, 46, and 57 ms and compare them to predictions. Two measurements of bolometer absorption efficiency show high ($\sim$0.9) efficiency at 150 GHz and medium ($\sim$0.35, and $\sim$0.25) at the two higher bands, respectively. We measure a median total optical load of 3.6, 5.3 and 5.0 pW absorbed at the three bands, respectively. EBEX pioneered the use of the digital version of the frequency domain multiplexing (FDM) system which multiplexed the bias and readout of 16 bolometers onto two wires. We present accounting of the measured noise equivalent power. The median per-detector noise equivalent temperatures referred to a black body with a temperature of 2.725 K are 400, 920, and 14500 $\mu$K$\sqrt{s}$ for the three bands, respectively. We compare these values to our pre-flight predictions and to a previous balloon payload, discuss the sources of excess noise, and the path for a future payload to make full use of the balloon environment.

[13]  http://arxiv.org/abs/1801.01497v2 [ html pdf ]
Massive optimal data compression and density estimation for scalable, likelihood-free inference in cosmology
Justin Alsing, Benjamin Wandelt, Stephen Feeney

Many statistical models in cosmology can be simulated forwards but have intractable likelihood functions. Likelihood-free inference methods allow us to perform Bayesian inference from these models using only forward simulations, free from any likelihood assumptions or approximations. Likelihood-free inference generically involves simulating mock data and comparing to the observed data; this comparison in data-space suffers from the curse of dimensionality and requires compression of the data to a small number of summary statistics to be tractable. In this paper we use massive asymptotically-optimal data compression to reduce the dimensionality of the data-space to just one number per parameter, providing a natural and optimal framework for summary statistic choice for likelihood-free inference. Secondly, we present the first cosmological application of Density Estimation Likelihood-Free Inference (\textsc{delfi}), which learns a parameterized model for joint distribution of data and parameters, yielding both the parameter posterior and the model evidence. This approach is conceptually simple, requires less tuning than traditional Approximate Bayesian Computation approaches to likelihood-free inference and can give high-fidelity posteriors from orders of magnitude fewer forward simulations. As an additional bonus, it enables parameter inference and Bayesian model comparison simultaneously. We demonstrate Density Estimation Likelihood-Free Inference with massive data compression on an analysis of the joint light-curve analysis supernova data, as a simple validation case study. We show that high-fidelity posterior inference is possible for full-scale cosmological data analyses with as few as $\sim 10^4$ simulations, with substantial scope for further improvement, demonstrating the scalability of likelihood-free inference to large and complex cosmological datasets.

[14]  http://arxiv.org/abs/1707.00007v2 [ html pdf ]
Clarifying the Hubble constant tension with a Bayesian hierarchical model of the local distance ladder
Stephen M. Feeney, Daniel J. Mortlock, Niccolò Dalmasso

Estimates of the Hubble constant, $H_0$, from the distance ladder and the cosmic microwave background (CMB) differ at the $\sim$3-$\sigma$ level, indicating a potential issue with the standard $\Lambda$CDM cosmology. Interpreting this tension correctly requires a model comparison calculation depending on not only the traditional `$n$-$\sigma$' mismatch but also the tails of the likelihoods. Determining the form of the tails of the local $H_0$ likelihood is impossible with the standard Gaussian least-squares approximation, as it requires using non-Gaussian distributions to faithfully represent anchor likelihoods and model outliers in the Cepheid and supernova (SN) populations, and simultaneous fitting of the full distance-ladder dataset to correctly propagate uncertainties. We have developed a Bayesian hierarchical model that describes the full distance ladder, from nearby geometric anchors through Cepheids to Hubble-Flow SNe. This model does not rely on any distributions being Gaussian, allowing outliers to be modeled and obviating the need for arbitrary data cuts. Sampling from the $\sim$3000-parameter joint posterior using Hamiltonian Monte Carlo, we find $H_0$ = (72.72 $\pm$ 1.67) ${\rm km\,s^{-1}\,Mpc^{-1}}$ when applied to the outlier-cleaned Riess et al. (2016) data, and ($73.15 \pm 1.78$) ${\rm km\,s^{-1}\,Mpc^{-1}}$ with SN outliers reintroduced. Our high-fidelity sampling of the low-$H_0$ tail of the distance-ladder likelihood allows us to apply Bayesian model comparison to assess the evidence for deviation from $\Lambda$CDM. We set up this comparison to yield a lower limit on the odds of the underlying model being $\Lambda$CDM given the distance-ladder and Planck XIII (2016) CMB data. The odds against $\Lambda$CDM are at worst 10:1 or 7:1, depending on whether the SNe outliers are cut or modeled, or 60:1 if an approximation to the Planck Int. XLVI (2016) likelihood is used.

[15]  http://arxiv.org/abs/1705.02907v2 [ html pdf ]
A Measurement of the Cosmic Microwave Background $B$-Mode Polarization Power Spectrum at Sub-Degree Scales from 2 years of POLARBEAR Data
The POLARBEAR Collaboration, P. A. R. Ade, M. Aguilar, Y. Akiba, K. Arnold, C. Baccigalupi, D. Barron, D. Beck, F. Bianchini, D. Boettger, J. Borrill, S. Chapman, Y. Chinone, K. Crowley, A. Cukierman, M. Dobbs, A. Ducout, R. Dünner, T. Elleflot, J. Errard, G. Fabbian, S. M. Feeney, C. Feng, T. Fujino, N. Galitzki, A. Gilbert, N. Goeckner-Wald, J. Groh, T. Hamada, G. Hall, N. W. Halverson, M. Hasegawa, M. Hazumi, C. Hill, L. Howe, Y. Inoue, G. C. Jaehnig, A. H. Jaffe, O. Jeong, D. Kaneko, N. Katayama, B. Keating, R. Keskitalo, T. Kisner, N. Krachmalnicoff, A. Kusaka, M. Le Jeune, A. T. Lee, E. M. Leitch, D. Leon, E. Linder, L. Lowry, F. Matsuda, T. Matsumura, Y. Minami, J. Montgomery, M. Navaroli, H. Nishino, H. Paar, J. Peloton, A. T. P. Pham, D. Poletti, G. Puglisi, C. L. Reichardt, P. L. Richards, C. Ross, Y. Segawa, B. D. Sherwin, M. Silva-Feaver, P. Siritanasak, N. Stebor, R. Stompor, A. Suzuki, O. Tajima, S. Takakura, S. Takatori, D. Tanabe, G. P. Teply, T. Tomaru, C. Tucker, N. Whitehorn, A. Zahn

We report an improved measurement of the cosmic microwave background (CMB) $B$-mode polarization power spectrum with the POLARBEAR experiment at 150 GHz. By adding new data collected during the second season of observations (2013-2014) to re-analyzed data from the first season (2012-2013), we have reduced twofold the band-power uncertainties. The band powers are reported over angular multipoles $500 \leq \ell \leq 2100$, where the dominant $B$-mode signal is expected to be due to the gravitational lensing of $E$-modes. We reject the null hypothesis of no $B$-mode polarization at a confidence of 3.1$\sigma$ including both statistical and systematic uncertainties. We test the consistency of the measured $B$-modes with the $\Lambda$ Cold Dark Matter ($\Lambda$CDM) framework by fitting for a single lensing amplitude parameter $A_L$ relative to the Planck best-fit model prediction. We obtain $A_L = 0.60 ^{+0.26} _{-0.24} ({\rm stat}) ^{+0.00} _{-0.04}({\rm inst}) \pm 0.14 ({\rm foreground}) \pm 0.04 ({\rm multi})$, where $A_{L}=1$ is the fiducial $\Lambda$CDM value, and the details of the reported uncertainties are explained later in the manuscript.

[16]  http://arxiv.org/abs/1611.10347v2 [ html pdf ]
Wavelet-Bayesian inference of cosmic strings embedded in the cosmic microwave background
J. D. McEwen, S. M. Feeney, H. V. Peiris, Y. Wiaux, C. Ringeval, F. R. Bouchet

Cosmic strings are a well-motivated extension to the standard cosmological model and could induce a subdominant component in the anisotropies of the cosmic microwave background (CMB), in addition to the standard inflationary component. The detection of strings, while observationally challenging, would provide a direct probe of physics at very high energy scales. We develop a new framework for cosmic string inference, constructing a Bayesian analysis in wavelet space where the string-induced CMB component has distinct statistical properties to the standard inflationary component. Our wavelet-Bayesian framework provides a principled approach to compute the posterior distribution of the string tension $G\mu$ and the Bayesian evidence ratio comparing the string model to the standard inflationary model. Furthermore, we present a technique to recover an estimate of any string-induced CMB map embedded in observational data. Using Planck-like simulations we demonstrate the application of our framework and evaluate its performance. The method is sensitive to $G\mu \sim 5 \times 10^{-7}$ for Nambu-Goto string simulations that include an integrated Sachs-Wolfe (ISW) contribution only and do not include any recombination effects, before any parameters of the analysis are optimised. The sensitivity of the method compares favourably with other techniques applied to the same simulations.

[17]  http://arxiv.org/abs/1704.05764v3 [ html pdf ]
Exploring cosmic origins with CORE: effects of observer peculiar motion
C. Burigana, C. S. Carvalho, T. Trombetti, A. Notari, M. Quartin, G. De Gasperis, A. Buzzelli, N. Vittorio, G. De Zotti, P. de Bernardis, J. Chluba, M. Bilicki, L. Danese, J. Delabrouille, L. Toffolatti, A. Lapi, M. Negrello, P. Mazzotta, D. Scott, D. Contreras, A. Achucarro, P. Ade, R. Allison, M. Ashdown, M. Ballardini, A. J. Banday, R. Banerji, J. Bartlett, N. Bartolo, S. Basak, M. Bersanelli, A. Bonaldi, M. Bonato, J. Borrill, F. Bouchet, F. Boulanger, T. Brinckmann, M. Bucher, P. Cabella, Z. -Y. Cai, M. Calvo, G. Castellano, A. Challinor, S. Clesse, I. Colantoni, A. Coppolecchia, M. Crook, G. D'Alessandro, J. -M. Diego, A. Di Marco, E. Di Valentino, J. Errard, S. Feeney, R. Fernandez-Cobos, S. Ferraro, F. Finelli, F. Forastieri, S. Galli, R. Genova-Santos, M. Gerbino, J. Gonzalez-Nuevo, S. Grandis, J. Greenslade, S. Hagstotz, S. Hanany, W. Handley, C. Hernandez-Monteagudo, C. Hervias-Caimapo, M. Hills, E. Hivon, K. Kiiveri, T. Kisner, T. Kitching, M. Kunz, H. Kurki-Suonio, L. Lamagna, A. Lasenby, M. Lattanzi, J. Lesgourgues, M. Liguori, V. Lindholm, M. Lopez-Caniego, G. Luzzi, B. Maffei, N. Mandolesi, E. Martinez-Gonzalez, C. J. A. P. Martins, S. Masi, D. McCarthy, A. Melchiorri, J. -B. Melin, D. Molinari, A. Monfardini, P. Natoli, A. Paiella, D. Paoletti, G. Patanchon, M. Piat, G. Pisano, L. Polastri, G. Polenta, A. Pollo, V. Poulin, M. Remazeilles, M. Roman, J. -A. Rubino-Martin, L. Salvati, A. Tartari, M. Tomasi, D. Tramonte, N. Trappe, C. Tucker, J. Valiviita, R. Van de Weijgaert, B. van Tent, V. Vennin, P. Vielva, K. Young, M. Zannoni

We discuss the effects on the CMB, CIB, and thermal SZ effect due to the peculiar motion of an observer with respect to the CMB rest frame, which induces boosting effects. We investigate the scientific perspectives opened by future CMB space missions, focussing on the CORE proposal. The improvements in sensitivity offered by a mission like CORE, together with its high resolution over a wide frequency range, will provide a more accurate estimate of the CMB dipole. The extension of boosting effects to polarization and cross-correlations will enable a more robust determination of purely velocity-driven effects that are not degenerate with the intrinsic CMB dipole, allowing us to achieve a S/N ratio of 13; this improves on the Planck detection and essentially equals that of an ideal cosmic-variance-limited experiment up to a multipole l of 2000. Precise inter-frequency calibration will offer the opportunity to constrain or even detect CMB spectral distortions, particularly from the cosmological reionization, because of the frequency dependence of the dipole spectrum, without resorting to precise absolute calibration. The expected improvement with respect to COBE-FIRAS in the recovery of distortion parameters (in principle, a factor of several hundred for an ideal experiment with the CORE configuration) ranges from a factor of several up to about 50, depending on the quality of foreground removal and relative calibration. Even for 1% accuracy in both foreground removal and relative calibration at an angular scale of 1 deg, we find that dipole analyses for a mission like CORE will be able to improve the recovery of the CIB spectrum amplitude by a factor of 17 in comparison with current results based on FIRAS. In addition to the scientific potential of a mission like CORE for these analyses, synergies with other planned and ongoing projects are also discussed.

[18]  http://arxiv.org/abs/1707.04224v1 [ html pdf ]
Exploring cosmic origins with CORE: mitigation of systematic effects
P. Natoli, M. Ashdown, R. Banerji, J. Borrill, A. Buzzelli, G. de Gasperis, J. Delabrouille, E. Hivon, D. Molinari, G. Patanchon, L. Polastri, M. Tomasi, F. R. Bouchet, S. Henrot-Versillé, D. T. Hoang, R. Keskitalo, K. Kiiveri, T. Kisner, V. Lindholm, D. McCarthy, F. Piacentini, O. Perdereau, G. Polenta, M. Tristram, A. Achucarro, P. Ade, R. Allison, C. Baccigalupi, M. Ballardini, A. J. Banday, J. Bartlett, N. Bartolo, S. Basak, J. Baselmans, D. Baumann, M. Bersanelli, A. Bonaldi, M. Bonato, F. Boulanger, T. Brinckmann, M. Bucher, C. Burigana, Z. -Y. Cai, M. Calvo, C. -S. Carvalho, G. Castellano, A. Challinor, J. Chluba, S. Clesse, I. Colantoni, A. Coppolecchia, M. Crook, G. D'Alessandro, P. de Bernardis, G. De Zotti, E. Di Valentino, J. -M. Diego, J. Errard, S. Feeney, R. Fernandez-Cobos, F. Finelli, F. Forastieri, S. Galli, R. Genova-Santos, M. Gerbino, J. Gonzalez-Nuevo, S. Grandis, J. Greenslade, A. Gruppuso, S. Hagstotz, S. Hanany, W. Handley, C. Hernandez-Monteagudo, C. Hervias-Caimapo, M. Hills, E. Keihänen, T. Kitching, M. Kunz, H. Kurki-Suonio, L. Lamagna, A. Lasenby, M. Lattanzi, J. Lesgourgues, A. Lewis, M. Liguori, M. López-Caniego, G. Luzzi, B. Maffei, N. Mandolesi, E. Martinez-Gonzalez, C. J. A. P. Martins, S. Masi, A. Melchiorri, J. -B. Melin, M. Migliaccio, A. Monfardini, M. Negrello, A. Notari, L. Pagano, A. Paiella, D. Paoletti, M. Piat, G. Pisano, A. Pollo, V. Poulin, M. Quartin, M. Remazeilles, M. Roman, G. Rossi, J. -A. Rubino-Martin, L. Salvati, G. Signorelli, A. Tartari, D. Tramonte, N. Trappe, T. Trombetti, C. Tucker, J. Valiviita, R. Van de Weijgaert, B. van Tent, V. Vennin, P. Vielva, N. Vittorio, C. Wallis, K. Young, M. Zannoni

We present an analysis of the main systematic effects that could impact the measurement of CMB polarization with the proposed CORE space mission. We employ timeline-to-map simulations to verify that the CORE instrumental set-up and scanning strategy allow us to measure sky polarization to a level of accuracy adequate to the mission science goals. We also show how the CORE observations can be processed to mitigate the level of contamination by potentially worrying systematics, including intensity-to-polarization leakage due to bandpass mismatch, asymmetric main beams, pointing errors and correlated noise. We use analysis techniques that are well validated on data from current missions such as Planck to demonstrate how the residual contamination of the measurements by these effects can be brought to a level low enough not to hamper the scientific capability of the mission, nor significantly increase the overall error budget. We also present a prototype of the CORE photometric calibration pipeline, based on that used for Planck, and discuss its robustness to systematics, showing how CORE can achieve its calibration requirements. While a fine-grained assessment of the impact of systematics requires a level of knowledge of the system that can only be achieved in a future study phase, the analysis presented here strongly suggests that the main areas of concern for the CORE mission can be addressed using existing knowledge, techniques and algorithms.

[19]  http://arxiv.org/abs/1704.04501v2 [ html pdf ]
Exploring Cosmic Origins with CORE: B-mode Component Separation
M. Remazeilles, A. J. Banday, C. Baccigalupi, S. Basak, A. Bonaldi, G. De Zotti, J. Delabrouille, C. Dickinson, H. K. Eriksen, J. Errard, R. Fernandez-Cobos, U. Fuskeland, C. Hervías-Caimapo, M. López-Caniego, E. Martinez-González, M. Roman, P. Vielva, I. Wehus, A. Achucarro, P. Ade, R. Allison, M. Ashdown, M. Ballardini, R. Banerji, N. Bartolo, J. Bartlett, D. Baumann, M. Bersanelli, M. Bonato, J. Borrill, F. Bouchet, F. Boulanger, T. Brinckmann, M. Bucher, C. Burigana, A. Buzzelli, Z. -Y. Cai, M. Calvo, C. -S. Carvalho, G. Castellano, A. Challinor, J. Chluba, S. Clesse, I. Colantoni, A. Coppolecchia, M. Crook, G. D'Alessandro, P. de Bernardis, G. de Gasperis, J. -M. Diego, E. Di Valentino, S. Feeney, S. Ferraro, F. Finelli, F. Forastieri, S. Galli, R. Genova-Santos, M. Gerbino, J. González-Nuevo, S. Grandis, J. Greenslade, S. Hagstotz, S. Hanany, W. Handley, C. Hernandez-Monteagudo, M. Hills, E. Hivon, K. Kiiveri, T. Kisner, T. Kitching, M. Kunz, H. Kurki-Suonio, L. Lamagna, A. Lasenby, M. Lattanzi, J. Lesgourgues, A. Lewis, M. Liguori, V. Lindholm, G. Luzzi, B. Maffei, C. J. A. P. Martins, S. Masi, D. McCarthy, J. -B. Melin, A. Melchiorri, D. Molinari, A. Monfardini, P. Natoli, M. Negrello, A. Notari, A. Paiella, D. Paoletti, G. Patanchon, M. Piat, G. Pisano, L. Polastri, G. Polenta, A. Pollo, V. Poulin, M. Quartin, J. -A. Rubino-Martin, L. Salvati, A. Tartari, M. Tomasi, D. Tramonte, N. Trappe, T. Trombetti, C. Tucker, J. Valiviita, R. Van de Weijgaert, B. van Tent, V. Vennin, N. Vittorio, K. Young, M. Zannoni

We demonstrate that, for the baseline design of the CORE satellite mission, the polarized foregrounds can be controlled at the level required to allow the detection of the primordial cosmic microwave background (CMB) $B$-mode polarization with the desired accuracy at both reionization and recombination scales, for tensor-to-scalar ratio values of ${r\gtrsim 5\times 10^{-3}}$. We consider detailed sky simulations based on state-of-the-art CMB observations that consist of CMB polarization with $\tau=0.055$ and tensor-to-scalar values ranging from $r=10^{-2}$ to $10^{-3}$, Galactic synchrotron, and thermal dust polarization with variable spectral indices over the sky, polarized anomalous microwave emission, polarized infrared and radio sources, and gravitational lensing effects. Using both parametric and blind approaches, we perform full component separation and likelihood analysis of the simulations, allowing us to quantify both uncertainties and biases on the reconstructed primordial $B$-modes. Under the assumption of perfect control of lensing effects, CORE would measure an unbiased estimate of $r=\left(5 \pm 0.4\right)\times 10^{-3}$ after foreground cleaning. In the presence of both gravitational lensing effects and astrophysical foregrounds, the significance of the detection is lowered, with CORE achieving a $4\sigma$-measurement of $r=5\times 10^{-3}$ after foreground cleaning and $60$% delensing. For lower tensor-to-scalar ratios ($r=10^{-3}$) the overall uncertainty on $r$ is dominated by foreground residuals, not by the 40% residual of lensing cosmic variance. Moreover, the residual contribution of unprocessed polarized point-sources can be the dominant foreground contamination to primordial B-modes at this $r$ level, even on relatively large angular scales, $\ell \sim 50$. Finally, we report two sources of potential bias for the detection of the primordial $B$-modes.[abridged]

[20]  http://arxiv.org/abs/1609.07263v4 [ html pdf ]
Exploring Cosmic Origins with CORE: Extragalactic sources in Cosmic Microwave Background maps
G. De Zotti, J. Gonzalez-Nuevo, M. Lopez-Caniego, M. Negrello, J. Greenslade, C. Hernandez-Monteagudo, J. Delabrouille, Z. -Y. Cai, M. Bonato, A. Achucarro, P. Ade, R. Allison, M. Ashdown, M. Ballardini, A. J. Banday, R. Banerji, J. G. Bartlett, N. Bartolo, S. Basak, M. Bersanelli, M. Biesiada, M. Bilicki, A. Bonaldi, J. Borrill, F. Bouchet, F. Boulanger, T. Brinckmann, M. Bucher, C. Burigana, A. Buzzelli, M. Calvo, C. S. Carvalho, M. G. Castellano, A. Challinor, J. Chluba, D. L. Clements, S. Clesse, S. Colafrancesco, I. Colantoni, A. Coppolecchia, M. Crook, G. D'Alessandro, P. de Bernardis, G. de Gasperis, J. M. Diego, E. Di Valentino, J. Errard, S. M. Feeney, R. Fernandez-Cobos, S. Ferraro, F. Finelli, F. Forastieri, S. Galli, R. T. Genova-Santos, M. Gerbino, S. Grandis, S. Hagstotz, S. Hanany, W. Handley, C. Hervias-Caimapo, M. Hills, E. Hivon, K. Kiiveri, T. Kisner, T. Kitching, M. Kunz, H. Kurki-Suonio, G. Lagache, L. Lamagna, A. Lasenby, M. Lattanzi, A. Le Brun, J. Lesgourgues, A. Lewis, M. Liguori, V. Lindholm, G. Luzzi, B. Maffei, N. Mandolesi, E. Martinez-Gonzalez, C. J. A. P. Martins, S. Masi, M. Massardi, D. McCarthy, A. Melchiorri, J. -B. Melin, D. Molinari, A. Monfardini, P. Natoli, A. Notari, A. Paiella, D. Paoletti, R. B. Partridge, G. Patanchon, M. Piat, G. Pisano, L. Polastri, G. Polenta, A. Pollo, V. Poulin, M. Quartin, M. Remazeilles, M. Roman, G. Rossi, B. F. Roukema, J. -A. Rubino-Martin, L. Salvati, D. Scott, S. Serjeant, A. Tartari, L. Toffolatti, M. Tomasi, N. Trappe, S. Triqueneaux, T. Trombetti, M. Tucci, C. Tucker, J. Valiviita, R. van de Weygaert, B. Van Tent, V. Vennin, P. Vielva, N. Vittorio, K. Young

We discuss the potential of a next generation space-borne Cosmic Microwave Background (CMB) experiment for studies of extragalactic sources. Our analysis has particular bearing on the definition of the future space project, CORE, that has been submitted in response to ESA's call for a Medium-size mission opportunity as the successor of the Planck satellite. Even though the effective telescope size will be somewhat smaller than that of Planck, CORE will have a considerably better angular resolution at its highest frequencies, since, in contrast with Planck, it will be diffraction limited at all frequencies. The improved resolution implies a considerable decrease of the source confusion, i.e. substantially fainter detection limits. In particular, CORE will detect thousands of strongly lensed high-z galaxies distributed over the full sky. The extreme brightness of these galaxies will make it possible to study them, via follow-up observations, in extraordinary detail. Also, the CORE resolution matches the typical sizes of high-z galaxy proto-clusters much better than the Planck resolution, resulting in a much higher detection efficiency; these objects will be caught in an evolutionary phase beyond the reach of surveys in other wavebands. Furthermore, CORE will provide unique information on the evolution of the star formation in virialized groups and clusters of galaxies up to the highest possible redshifts. Finally, thanks to its very high sensitivity, CORE will detect the polarized emission of thousands of radio sources and, for the first time, of dusty galaxies, at mm and sub-mm wavelengths, respectively.

[21]  http://arxiv.org/abs/1610.07604v2 [ html pdf ]
Cosmic Microwave Background Science at Commercial Airline Altitudes
Stephen M. Feeney, Jon E. Gudmundsson, Hiranya V. Peiris, Licia Verde, Josquin Errard

Obtaining high-sensitivity measurements of degree-scale cosmic microwave background (CMB) polarization is the most direct path to detecting primordial gravitational waves. Robustly recovering any primordial signal from the dominant foreground emission will require high-fidelity observations at multiple frequencies, with excellent control of systematics. We explore the potential for a new platform for CMB observations, the Airlander 10 hybrid air vehicle, to perform this task. We show that the Airlander 10 platform, operating at commercial airline altitudes, is well-suited to mapping frequencies above 220 GHz, which are critical for cleaning CMB maps of dust emission. Optimizing the distribution of detectors across frequencies, we forecast the ability of Airlander 10 to clean foregrounds of varying complexity as a function of altitude, demonstrating its complementarity with both existing (Planck) and ongoing (C-BASS) foreground observations. This novel platform could play a key role in defining our ultimate view of the polarized microwave sky.

[22]  http://arxiv.org/abs/1612.08270v2 [ html pdf ]
Exploring Cosmic Origins with CORE: Inflation
CORE Collaboration, Fabio Finelli, Martin Bucher, Ana Achúcarro, Mario Ballardini, Nicola Bartolo, Daniel Baumann, Sébastien Clesse, Josquin Errard, Will Handley, Mark Hindmarsh, Kimmo Kiiveri, Martin Kunz, Anthony Lasenby, Michele Liguori, Daniela Paoletti, Christophe Ringeval, Jussi Väliviita, Bartjan van Tent, Vincent Vennin, Rupert Allison, Frederico Arroja, Marc Ashdown, A. J. Banday, Ranajoy Banerji, James G. Bartlett, Soumen Basak, Jochem Baselmans, Paolo de Bernardis, Marco Bersanelli, Anna Bonaldi, Julian Borril, François R. Bouchet, François Boulanger, Thejs Brinckmann, Carlo Burigana, Alessandro Buzzelli, Zhen-Yi Cai, Martino Calvo, Carla Sofia Carvalho, Gabriella Castellano, Anthony Challinor, Jens Chluba, Ivan Colantoni, Martin Crook, Giuseppe D'Alessandro, Guido D'Amico, Jacques Delabrouille, Vincent Desjacques, Gianfranco De Zotti, Jose Maria Diego, Eleonora Di Valentino, Stephen Feeney, James R. Fergusson, Raul Fernandez-Cobos, Simone Ferraro, Francesco Forastieri, Silvia Galli, Juan García-Bellido, Giancarlo de Gasperis, Ricardo T. Génova-Santos, Martina Gerbino, Joaquin González-Nuevo, Sebastian Grandis, Josh Greenslade, Steffen Hagstotz, Shaul Hanany, Dhiraj K. Hazra, Carlos Hernández-Monteagudo, Carlos Hervias-Caimapo, Matthew Hills, Eric Hivon, Bin Hu, Ted Kisner, Thomas Kitching, Ely D. Kovetz, Hannu Kurki-Suonio, Luca Lamagna, Massimiliano Lattanzi, Julien Lesgourgues, Antony Lewis, Valtteri Lindholm, Joanes Lizarraga, Marcos López-Caniego, Gemma Luzzi, Bruno Maffei, Nazzareno Mandolesi, Enrique Martínez-González, Carlos J. A. P. Martins, Silvia Masi, Darragh McCarthy, Sabino Matarrese, Alessandro Melchiorri, Jean-Baptiste Melin, Diego Molinari, Alessandro Monfardini, Paolo Natoli, Mattia Negrello, Alessio Notari, Filippo Oppizzi, Alessandro Paiella, Enrico Pajer, Guillaume Patanchon, Subodh P. Patil, Michael Piat, Giampaolo Pisano, Linda Polastri, Gianluca Polenta, Agnieszka Pollo, Vivian Poulin, Miguel Quartin, Andrea Ravenni, Mathieu Remazeilles, Alessandro Renzi, Diederik Roest, Matthieu Roman, Jose Alberto Rubiño-Martin, Laura Salvati, Alexei A. Starobinsky, Andrea Tartari, Gianmassimo Tasinato, Maurizio Tomasi, Jesús Torrado, Neil Trappe, Tiziana Trombetti, Carole Tucker, Marco Tucci, Jon Urrestilla, Rien van de Weygaert, Patricio Vielva, Nicola Vittorio, Karl Young

We forecast the scientific capabilities to improve our understanding of cosmic inflation of CORE, a proposed CMB space satellite submitted in response to the ESA fifth call for a medium-size mission opportunity. The CORE satellite will map the CMB anisotropies in temperature and polarization in 19 frequency channels spanning the range 60-600 GHz. CORE will have an aggregate noise sensitivity of $1.7 \mu$K$\cdot \,$arcmin and an angular resolution of 5' at 200 GHz. We explore the impact of telescope size and noise sensitivity on the inflation science return by making forecasts for several instrumental configurations. This study assumes that the lower and higher frequency channels suffice to remove foreground contaminations and complements other related studies of component separation and systematic effects, which will be reported in other papers of the series "Exploring Cosmic Origins with CORE." We forecast the capability to determine key inflationary parameters, to lower the detection limit for the tensor-to-scalar ratio down to the $10^{-3}$ level, to chart the landscape of single field slow-roll inflationary models, to constrain the epoch of reheating, thus connecting inflation to the standard radiation-matter dominated Big Bang era, to reconstruct the primordial power spectrum, to constrain the contribution from isocurvature perturbations to the $10^{-3}$ level, to improve constraints on the cosmic string tension to a level below the presumptive GUT scale, and to improve the current measurements of primordial non-Gaussianities down to the $f_{NL}^{\rm local} < 1$ level. For all the models explored, CORE alone will improve significantly on the present constraints on the physics of inflation. Its capabilities will be further enhanced by combining with complementary future cosmological observations.

[23]  http://arxiv.org/abs/1703.10456v1 [ html pdf ]
Exploring Cosmic Origins with CORE: Cluster Science
J. -B. Melin, A. Bonaldi, M. Remazeilles, S. Hagstotz, J. M. Diego, C. Hernández-Monteagudo, R. T. Génova-Santos, G. Luzzi, C. J. A. P. Martins, S. Grandis, J. J. Mohr, J. G. Bartlett, J. Delabrouille, S. Ferraro, D. Tramonte, J. A. Rubiño-Martín, J. F. Macìas-Pérez, A. Achúcarro, P. Ade, R. Allison, M. Ashdown, M. Ballardini, A. J. Banday, R. Banerji, N. Bartolo, S. Basak, J. Baselmans, K. Basu, R. A. Battye, D. Baumann, M. Bersanelli, M. Bonato, J. Borrill, F. Bouchet, F. Boulanger, T. Brinckmann, M. Bucher, C. Burigana, A. Buzzelli, Z. -Y. Cai, M. Calvo, C. S. Carvalho, M. G. Castellano, A. Challinor, J. Chluba, S. Clesse, S. Colafrancesco, I. Colantoni, A. Coppolecchia, M. Crook, G. D'Alessandro, P. de Bernardis, G. de Gasperis, M. De Petris, G. De Zotti, E. Di Valentino, J. Errard, S. M. Feeney, R. Fernández-Cobos, F. Finelli, F. Forastieri, S. Galli, M. Gerbino, J. González-Nuevo, J. Greenslade, S. Hanany, W. Handley, C. Hervias-Caimapo, M. Hills, E. Hivon, K. Kiiveri, T. Kisner, T. Kitching, M. Kunz, H. Kurki-Suonio, L. Lamagna, A. Lasenby, M. Lattanzi, A. M. C. Le Brun, J. Lesgourgues, A. Lewis, M. Liguori, V. Lindholm, M. Lopez-Caniego, B. Maffei, E. Martinez-Gonzalez, S. Masi, D. McCarthy, A. Melchiorri, D. Molinari, A. Monfardini, P. Natoli, M. Negrello, A. Notari, A. Paiella, D. Paoletti, G. Patanchon, M. Piat, G. Pisano, L. Polastri, G. Polenta, A. Pollo, V. Poulin, M. Quartin, M. Roman, L. Salvati, A. Tartari, M. Tomasi, N. Trappe, S. Triqueneaux, T. Trombetti, C. Tucker, J. Väliviita, R. van de Weygaert, B. Van Tent, V. Vennin, P. Vielva, N. Vittorio, J. Weller, K. Young, M. Zannoni

We examine the cosmological constraints that can be achieved with a galaxy cluster survey with the future CORE space mission. Using realistic simulations of the millimeter sky, produced with the latest version of the Planck Sky Model, we characterize the CORE cluster catalogues as a function of the main mission performance parameters. We pay particular attention to telescope size, key to improved angular resolution, and discuss the comparison and the complementarity of CORE with ambitious future ground-based CMB experiments that could be deployed in the next decade. A possible CORE mission concept with a 150 cm diameter primary mirror can detect of the order of 50,000 clusters through the thermal Sunyaev-Zeldovich effect (SZE). The total yield increases (decreases) by 25% when increasing (decreasing) the mirror diameter by 30 cm. The 150 cm telescope configuration will detect the most massive clusters ($>10^{14}\, M_\odot$) at redshift $z>1.5$ over the whole sky, although the exact number above this redshift is tied to the uncertain evolution of the cluster SZE flux-mass relation; assuming self-similar evolution, CORE will detect $\sim 500$ clusters at redshift $z>1.5$. This changes to 800 (200) when increasing (decreasing) the mirror size by 30 cm. CORE will be able to measure individual cluster halo masses through lensing of the cosmic microwave background anisotropies with a 1-$\sigma$ sensitivity of $4\times10^{14} M_\odot$, for a 120 cm aperture telescope, and $10^{14} M_\odot$ for a 180 cm one. [abridged]

[24]  http://arxiv.org/abs/1608.01624v2 [ html pdf ]
Making maps of Cosmic Microwave Background polarization for B-mode studies: the POLARBEAR example
Davide Poletti, Giulio Fabbian, Maude Le Jeune, Julien Peloton, Kam Arnold, Carlo Baccigalupi, Darcy Barron, Shawn Beckman, Julian Borrill, Scott Chapman, Yuji Chinone, Ari Cukierman, Anne Ducout, Tucker Elleflot, Josquin Errard, Stephen Feeney, Neil Goeckner-Wald, John Groh, Grantland Hall, Masaya Hasegawa, Masashi Hazumi, Charles Hill, Logan Howe, Yuki Inoue, Andrew H. Jaffe, Oliver Jeong, Nobuhiko Katayama, Brian Keating, Reijo Keskitalo, Theodore Kisner, Akito Kusaka, Adrian T. Lee, David Leon, Eric Linder, Lindsay Lowry, Frederick Matsuda, Martin Navaroli, Hans Paar, Giuseppe Puglisi, Christian L. Reichardt, Colin Ross, Praween Siritanasak, Nathan Stebor, Bryan Steinbach, Radek Stompor, Aritoki Suzuki, Osamu Tajima, Grant Teply, Nathan Whitehorn

Analysis of cosmic microwave background (CMB) datasets typically requires some filtering of the raw time-ordered data. Filtering is frequently used to minimize the impact of low frequency noise, atmospheric contributions and/or scan synchronous signals on the resulting maps. In this work we explicitly construct a general filtering operator, which can unambiguously remove any set of unwanted modes in the data, and then amend the map-making procedure in order to incorporate and correct for it. We show that such an approach is mathematically equivalent to the solution of a problem in which the sky signal and unwanted modes are estimated simultaneously and the latter are marginalized over. We investigate the conditions under which this amended map-making procedure can render an unbiased estimate of the sky signal in realistic circumstances. We then study the effects of time-domain filtering on the noise correlation structure in the map domain, as well as impact it may have on the performance of the popular pseudo-spectrum estimators. We conclude that although maps produced by the proposed estimators arguably provide the most faithful representation of the sky possible given the data, they may not straightforwardly lead to the best constraints on the power spectra of the underlying sky signal and special care may need to be taken to ensure this is the case. By contrast, simplified map-makers which do not explicitly correct for time-domain filtering, but leave it to subsequent steps in the data analysis, may perform equally well and be easier and faster to implement. We focus on polarization-sensitive measurements targeting the B-mode component of the CMB signal and apply the proposed methods to realistic simulations based on characteristics of an actual CMB polarization experiment, POLARBEAR.

[25]  http://arxiv.org/abs/1610.02743v1 [ html pdf ]
CMB-S4 Science Book, First Edition
Kevork N. Abazajian, Peter Adshead, Zeeshan Ahmed, Steven W. Allen, David Alonso, Kam S. Arnold, Carlo Baccigalupi, James G. Bartlett, Nicholas Battaglia, Bradford A. Benson, Colin A. Bischoff, Julian Borrill, Victor Buza, Erminia Calabrese, Robert Caldwell, John E. Carlstrom, Clarence L. Chang, Thomas M. Crawford, Francis-Yan Cyr-Racine, Francesco De Bernardis, Tijmen de Haan, Sperello di Serego Alighieri, Joanna Dunkley, Cora Dvorkin, Josquin Errard, Giulio Fabbian, Stephen Feeney, Simone Ferraro, Jeffrey P. Filippini, Raphael Flauger, George M. Fuller, Vera Gluscevic, Daniel Green, Daniel Grin, Evan Grohs, Jason W. Henning, J. Colin Hill, Renee Hlozek, Gilbert Holder, William Holzapfel, Wayne Hu, Kevin M. Huffenberger, Reijo Keskitalo, Lloyd Knox, Arthur Kosowsky, John Kovac, Ely D. Kovetz, Chao-Lin Kuo, Akito Kusaka, Maude Le Jeune, Adrian T. Lee, Marc Lilley, Marilena Loverde, Mathew S. Madhavacheril, Adam Mantz, David J. E. Marsh, Jeffrey McMahon, Pieter Daniel Meerburg, Joel Meyers, Amber D. Miller, Julian B. Munoz, Ho Nam Nguyen, Michael D. Niemack, Marco Peloso, Julien Peloton, Levon Pogosian, Clement Pryke, Marco Raveri, Christian L. Reichardt, Graca Rocha, Aditya Rotti, Emmanuel Schaan, Marcel M. Schmittfull, Douglas Scott, Neelima Sehgal, Sarah Shandera, Blake D. Sherwin, Tristan L. Smith, Lorenzo Sorbo, Glenn D. Starkman, Kyle T. Story, Alexander van Engelen, Joaquin D. Vieira, Scott Watson, Nathan Whitehorn, W. L. Kimmy Wu

This book lays out the scientific goals to be addressed by the next-generation ground-based cosmic microwave background experiment, CMB-S4, envisioned to consist of dedicated telescopes at the South Pole, the high Chilean Atacama plateau and possibly a northern hemisphere site, all equipped with new superconducting cameras. CMB-S4 will dramatically advance cosmological studies by crossing critical thresholds in the search for the B-mode polarization signature of primordial gravitational waves, in the determination of the number and masses of the neutrinos, in the search for evidence of new light relics, in constraining the nature of dark energy, and in testing general relativity on large scales.

[26]  http://arxiv.org/abs/1604.01024v3 [ html pdf ]
A framework for testing isotropy with the cosmic microwave background
Daniela Saadeh, Stephen M. Feeney, Andrew Pontzen, Hiranya V. Peiris, Jason D. McEwen

We present a new framework for testing the isotropy of the Universe using cosmic microwave background data, building on the nested-sampling ANICOSMO code. Uniquely, we are able to constrain the scalar, vector and tensor degrees of freedom alike; previous studies only considered the vector mode (linked to vorticity). We employ Bianchi type VII$_h$ cosmologies to model the anisotropic Universe, from which other types may be obtained by taking suitable limits. In a separate development, we improve the statistical analysis by including the effect of Bianchi power in the high-$\ell$, as well as the low-$\ell$, likelihood. To understand the effect of all these changes, we apply our new techniques to WMAP data. We find no evidence for anisotropy, constraining shear in the vector mode to $(\sigma_V/H)_0 < 1.7 \times 10^{-10}$ (95% CL). For the first time, we place limits on the tensor mode; unlike other modes, the tensor shear can grow from a near-isotropic early Universe. The limit on this type of shear is $(\sigma_{T,\rm reg}/H)_0 < 2.4 \times 10^{-7}$ (95% CL).

[27]  http://arxiv.org/abs/1605.07178v2 [ html pdf ]
How isotropic is the Universe?
Daniela Saadeh, Stephen M. Feeney, Andrew Pontzen, Hiranya V. Peiris, Jason D. McEwen

A fundamental assumption in the standard model of cosmology is that the Universe is isotropic on large scales. Breaking this assumption leads to a set of solutions to Einstein's field equations, known as Bianchi cosmologies, only a subset of which have ever been tested against data. For the first time, we consider all degrees of freedom in these solutions to conduct a general test of isotropy using cosmic microwave background temperature and polarization data from Planck. For the vector mode (associated with vorticity), we obtain a limit on the anisotropic expansion of $(\sigma_V/H)_0 < 4.7 \times 10^{-11}$ (95% CI), which is an order of magnitude tighter than previous Planck results that used CMB temperature only. We also place upper limits on other modes of anisotropic expansion, with the weakest limit arising from the regular tensor mode, $(\sigma_{T,\rm reg}/H)_0<1.0 \times 10^{-6}$ (95% CI). Including all degrees of freedom simultaneously for the first time, anisotropic expansion of the Universe is strongly disfavoured, with odds of 121,000:1 against.

[28]  http://arxiv.org/abs/1502.01593v2 [ html pdf ]
Planck 2015 results. XVIII. Background geometry & topology
Planck Collaboration, P. A. R. Ade, N. Aghanim, M. Arnaud, M. Ashdown, J. Aumont, C. Baccigalupi, A. J. Banday, R. B. Barreiro, N. Bartolo, S. Basak, E. Battaner, K. Benabed, A. Benoît, A. Benoit-Lévy, J. -P. Bernard, M. Bersanelli, P. Bielewicz, J. J. Bock, A. Bonaldi, L. Bonavera, J. R. Bond, J. Borrill, F. R. Bouchet, M. Bucher, C. Burigana, R. C. Butler, E. Calabrese, J. -F. Cardoso, A. Catalano, A. Challinor, A. Chamballu, H. C. Chiang, P. R. Christensen, S. Church, D. L. Clements, S. Colombi, L. P. L. Colombo, C. Combet, F. Couchot, A. Coulais, B. P. Crill, A. Curto, F. Cuttaia, L. Danese, R. D. Davies, R. J. Davis, P. de Bernardis, A. de Rosa, G. de Zotti, J. Delabrouille, F. -X. Désert, J. M. Diego, H. Dole, S. Donzelli, O. Doré, M. Douspis, A. Ducout, X. Dupac, G. Efstathiou, F. Elsner, T. A. Enßlin, H. K. Eriksen, S. Feeney, J. Fergusson, F. Finelli, O. Forni, M. Frailis, A. A. Fraisse, E. Franceschi, A. Frejsel, S. Galeotta, S. Galli, K. Ganga, M. Giard, Y. Giraud-Héraud, E. Gjerløw, J. González-Nuevo, K. M. Górski, S. Gratton, A. Gregorio, A. Gruppuso, J. E. Gudmundsson, F. K. Hansen, D. Hanson, D. L. Harrison, S. Henrot-Versillé, C. Hernández-Monteagudo, D. Herranz, S. R. Hildebrandt, E. Hivon, M. Hobson, W. A. Holmes, A. Hornstrup, W. Hovest, K. M. Huffenberger, G. Hurier, A. H. Jaffe, T. R. Jaffe, W. C. Jones, M. Juvela, E. Keihänen, R. Keskitalo, T. S. Kisner, J. Knoche, M. Kunz, H. Kurki-Suonio, G. Lagache, A. Lähteenmäki, J. -M. Lamarre, A. Lasenby, M. Lattanzi, C. R. Lawrence, R. Leonardi, J. Lesgourgues, F. Levrier, M. Liguori, P. B. Lilje, M. Linden-Vørnle, M. López-Caniego, P. M. Lubin, J. F. Macías-Pérez, G. Maggio, D. Maino, N. Mandolesi, A. Mangilli, M. Maris, P. G. Martin, E. Martínez-González, S. Masi, S. Matarrese, J. D. McEwen, P. McGehee, P. R. Meinhold, A. Melchiorri, L. Mendes, A. Mennella, M. Migliaccio, S. Mitra, M. -A. Miville-Deschênes, A. Moneti, L. Montier, G. Morgante, D. Mortlock, A. Moss, D. Munshi, J. A. Murphy, P. Naselsky, F. Nati, P. Natoli, C. B. Netterfield, H. U. Nørgaard-Nielsen, F. Noviello, D. Novikov, I. Novikov, C. A. Oxborrow, F. Paci, L. Pagano, F. Pajot, D. Paoletti, F. Pasian, G. Patanchon, H. V. Peiris, O. Perdereau, L. Perotto, F. Perrotta, V. Pettorino, F. Piacentini, M. Piat, E. Pierpaoli, D. Pietrobon, S. Plaszczynski, D. Pogosyan, E. Pointecouteau, G. Polenta, L. Popa, G. W. Pratt, G. Prézeau, S. Prunet, J. -L. Puget, J. P. Rachen, R. Rebolo, M. Reinecke, M. Remazeilles, C. Renault, A. Renzi, I. Ristorcelli, G. Rocha, C. Rosset, M. Rossetti, G. Roudier, M. Rowan-Robinson, J. A. Rubiño-Martín, B. Rusholme, M. Sandri, D. Santos, M. Savelainen, G. Savini, D. Scott, M. D. Seiffert, E. P. S. Shellard, L. D. Spencer, V. Stolyarov, R. Stompor, R. Sudiwala, D. Sutton, A. -S. Suur-Uski, J. -F. Sygnet, J. A. Tauber, L. Terenzi, L. Toffolatti, M. Tomasi, M. Tristram, M. Tucci, J. Tuovinen, L. Valenziano, J. Valiviita, F. Van Tent, P. Vielva, F. Villa, L. A. Wade, B. D. Wandelt, I. K. Wehus, D. Yvon, A. Zacchei, A. Zonca

Full-sky CMB maps from the 2015 Planck release allow us to detect departures from global isotropy on the largest scales. We present the first searches using CMB polarization for correlations induced by a non-trivial topology with a fundamental domain intersecting, or nearly intersecting, the last scattering surface (at comoving distance $\chi_{rec}$). We specialize to flat spaces with toroidal and slab topologies, finding that explicit searches for the latter are sensitive to other topologies with antipodal symmetry. These searches yield no detection of a compact topology at a scale below the diameter of the last scattering surface. The limits on the radius $R_i$ of the largest sphere inscribed in the topological domain (at log-likelihood-ratio $\Delta\ln{L}>-5$ relative to a simply-connected flat Planck best-fit model) are $R_i>0.97\chi_{rec}$ for the cubic torus and $R_i>0.56\chi_{rec}$ for the slab. The limit for the cubic torus from the matched-circles search is numerically equivalent, $R_i>0.97\chi_{rec}$ (99% CL) from polarisation data alone. We also perform a Bayesian search for a Bianchi VII$_h$ geometry. In the non-physical setting where the Bianchi cosmology is decoupled from the standard cosmology, Planck temperature data favour the inclusion of a Bianchi component. However, the cosmological parameters generating this pattern are in strong disagreement with those found from CMB anisotropy data alone. Fitting the induced polarization pattern for this model to Planck data requires an amplitude of $-0.1\pm0.04$ compared to +1 if the model were to be correct. In the physical setting where the Bianchi parameters are fit simultaneously with the standard cosmological parameters, we find no evidence for a Bianchi VII$_h$ cosmology and constrain the vorticity of such models to $(\omega/H)_0<7.6\times10^{-10}$ (95% CL). [Abridged]

[29]  http://arxiv.org/abs/1509.06770v4 [ html pdf ]
Robust forecasts on fundamental physics from the foreground-obscured, gravitationally-lensed CMB polarization
Josquin Errard, Stephen M. Feeney, Hiranya V. Peiris, Andrew H. Jaffe

[Abridged] Recent results from the BICEP, Keck Array and Planck Collaborations demonstrate that Galactic foregrounds are an unavoidable obstacle in the search for evidence of inflationary gravitational waves in the cosmic microwave background (CMB) polarization. Beyond the foregrounds, the effect of lensing by intervening large-scale structure further obscures all but the strongest inflationary signals permitted by current data. With a plethora of ongoing and upcoming experiments aiming to measure these signatures, careful and self-consistent consideration of experiments' foreground- and lensing-removal capabilities is critical in obtaining credible forecasts of their performance. We investigate the capabilities of instruments such as Advanced ACTPol, BICEP3 and Keck Array, CLASS, EBEX10K, PIPER, Simons Array, SPT-3G and SPIDER, and projects as COrE+, LiteBIRD-ext, PIXIE and Stage IV, to clean contamination due to polarized synchrotron and dust from raw multi-frequency data, and remove lensing from the resulting co-added CMB maps (either using iterative CMB-only techniques or through cross-correlation with external data). Incorporating these effects, we present forecasts for the constraining power of these experiments in terms of inflationary physics, the neutrino sector, and dark energy parameters. Made publicly available through an online interface, this tool enables the next generation of CMB experiments to foreground-proof their designs, optimize their frequency coverage to maximize scientific output, and determine where cross-experimental collaboration would be most beneficial. We find that analyzing data from ground, balloon and space instruments in complementary combinations can significantly improve component separation performance, delensing, and cosmological constraints over individual datasets.

[30]  http://arxiv.org/abs/1601.07923v1 [ html pdf ]
Temperature calibration of the E and B experiment
Francois Aubin, Asad M. Aboobaker, Peter Ade, Derek Araujo, Carlo Baccigalupi, Chaoyun Bao, Julian Borrill, Daniel Chapman, Joy Didier, Matt Dobbs, Stephen Feeney, Christopher Geach, Shaul Hanany, Kyle Helson, Seth Hillbrand, Gene Hilton, Johannes Hubmayr, Andrew Jaffe, Bradley Johnson, Terry Jones, Theodore Kisner, Jeff Klein, Andrei Korotkov, Adrian Lee, Lorne Levinson, Michele Limon, Kevin Macdermid, Valerie Marchenko, Amber D. Miller, Michael Milligan, Enzo Pascale, Giuseppe Puglisi, Kate Raach, Britt Reichborn-Kjennerud, Carl Reintsema, Ilan Sagiv, Graeme Smecher, Radek Stompor, Matthieu Tristram, Gregory S. Tucker, Ben Westbrook, Karl Young, Kyle Zilic

The E and B Experiment (EBEX) is a balloon-borne polarimeter designed to measure the polarization of the cosmic microwave background radiation and to characterize the polarization of galactic dust. EBEX was launched December 29, 2012 and circumnavigated Antarctica observing $\sim$6,000 square degrees of sky during 11 days at three frequency bands centered around 150, 250 and 410 GHz. EBEX was the first experiment to operate a kilo-pixel array of transition-edge sensor bolometers and a continuously rotating achromatic half-wave plate aboard a balloon platform. It also pioneered the use of detector readout based on digital frequency domain multiplexing. We describe the temperature calibration of the experiment. The gain response of the experiment is calibrated using a two-step iterative process. We use signals measured on passes across the Galactic plane to convert from readout-system counts to power. The effective smoothing scale of the EBEX optics and the star camera-to-detector offset angles are determined through \c{hi}2 minimization using the compact HII region RCW 38. This two-step process is initially performed with parameters measured before the EBEX 2013 flight and then repeated until the calibration factor and parameters converge.

[31]  http://arxiv.org/abs/1509.02461v2 [ html pdf ]
POLARBEAR Constraints on Cosmic Birefringence and Primordial Magnetic Fields
POLARBEAR Collaboration, Peter A. R. Ade, Kam Arnold, Matt Atlas, Carlo Baccigalupi, Darcy Barron, David Boettger, Julian Borrill, Scott Chapman, Yuji Chinone, Ari Cukierman, Matt Dobbs, Anne Ducout, Rolando Dunner, Tucker Elleflot, Josquin Errard, Giulio Fabbian, Stephen Feeney, Chang Feng, Adam Gilbert, Neil Goeckner-Wald, John Groh, Grantland Hall, Nils W. Halverson, Masaya Hasegawa, Kaori Hattori, Masashi Hazumi, Charles Hill, William L. Holzapfel, Yasuto Hori, Logan Howe, Yuki Inoue, Gregory C. Jaehnig, Andrew H. Jaffe, Oliver Jeong, Nobuhiko Katayama, Jonathan P. Kaufman, Brian Keating, Zigmund Kermish, Reijo Keskitalo, Theodore Kisner, Akito Kusaka, Maude Le Jeune, Adrian T. Lee, Erik M. Leitch, David Leon, Yun Li, Eric Linder, Lindsay Lowry, Frederick Matsuda, Tomotake Matsumura, Nathan Miller, Josh Montgomery, Michael J. Myers, Martin Navaroli, Haruki Nishino, Takahiro Okamura, Hans Paar, Julien Peloton, Levon Pogosian, Davide Poletti, Giuseppe Puglisi, Christopher Raum, Gabriel Rebeiz, Christian L. Reichardt, Paul L. Richards, Colin Ross, Kaja M. Rotermund, David E. Schenck, Blake D. Sherwin, Meir Shimon, Ian Shirley, Praween Siritanasak, Graeme Smecher, Nathan Stebor, Bryan Steinbach, Aritoki Suzuki, Jun-ichi Suzuki, Osamu Tajima, Satoru Takakura, Alexei Tikhomirov, Takayuki Tomaru, Nathan Whitehorn, Brandon Wilson, Amit Yadav, Alex Zahn, Oliver Zahn

We constrain anisotropic cosmic birefringence using four-point correlations of even-parity $E$-mode and odd-parity $B$-mode polarization in the cosmic microwave background measurements made by the POLARization of the Background Radiation (POLARBEAR) experiment in its first season of observations. We find that the anisotropic cosmic birefringence signal from any parity-violating processes is consistent with zero. The Faraday rotation from anisotropic cosmic birefringence can be compared with the equivalent quantity generated by primordial magnetic fields if they existed. The POLARBEAR nondetection translates into a 95% confidence level (C.L.) upper limit of 93 nanogauss (nG) on the amplitude of an equivalent primordial magnetic field inclusive of systematic uncertainties. This four-point correlation constraint on Faraday rotation is about 15 times tighter than the upper limit of 1380 nG inferred from constraining the contribution of Faraday rotation to two-point correlations of $B$-modes measured by Planck in 2015. Metric perturbations sourced by primordial magnetic fields would also contribute to the $B$-mode power spectrum. Using the POLARBEAR measurements of the $B$-mode power spectrum (two-point correlation), we set a 95% C.L. upper limit of 3.9 nG on primordial magnetic fields assuming a flat prior on the field amplitude. This limit is comparable to what was found in the Planck 2015 two-point correlation analysis with both temperature and polarization. We perform a set of systematic error tests and find no evidence for contamination. This work marks the first time that anisotropic cosmic birefringence or primordial magnetic fields have been constrained from the ground at subdegree scales.

[32]  http://arxiv.org/abs/1512.07299v1 [ html pdf ]
The POLARBEAR-2 and the Simons Array Experiment
A. Suzuki, P. Ade, Y. Akiba, C. Aleman, K. Arnold, C. Baccigalupi, B. Barch, D. Barron, A. Bender, D. Boettger, J. Borrill, S. Chapman, Y. Chinone, A. Cukierman, M. Dobbs, A. Ducout, R. Dunner, T. Elleflot, J. Errard, G. Fabbian, S. Feeney, C. Feng, T. Fujino, G. Fuller, A. Gilbert, N. Goeckner-Wald, J. Groh, T. De Haan, G. Hall, N. Halverson, T. Hamada, M. Hasegawa, K. Hattori, M. Hazumi, C. Hill, W. Holzapfel, Y. Hori, L. Howe, Y. Inoue, F. Irie, G. Jaehnig, A. Jaffe, O. Jeong, N. Katayama, J. Kaufman, K. Kazemzadeh, B. Keating, Z. Kermish, R. Keskitalo, T. Kisner, A. Kusaka, M. Le Jeune, A. Lee, D. Leon, E. Linder, L. Lowry, F. Matsuda, T. Matsumura, N. Miller, K. Mizukami, J. Montgomery, M. Navaroli, H. Nishino, J. Peloton, D. Poletti, G. Rebeiz, C. Raum, C. Reichardt, P. Richards, C. Ross, K. Rotermund, Y. Segawa, B. Sherwin, I. Shirley, P. Siritanasak, N. Stebor, R. Stompor, J. Suzuki, O. Tajima, S. Takada, S. Takakura, S. Takatori, A. Tikhomirov, T. Tomaru, B. Westbrook, N. Whitehorn, T. Yamashita, A. Zahn, O. Zahn

We present an overview of the design and status of the \Pb-2 and the Simons Array experiments. \Pb-2 is a Cosmic Microwave Background polarimetry experiment which aims to characterize the arc-minute angular scale B-mode signal from weak gravitational lensing and search for the degree angular scale B-mode signal from inflationary gravitational waves. The receiver has a 365~mm diameter focal plane cooled to 270~milli-Kelvin. The focal plane is filled with 7,588 dichroic lenslet-antenna coupled polarization sensitive Transition Edge Sensor (TES) bolometric pixels that are sensitive to 95~GHz and 150~GHz bands simultaneously. The TES bolometers are read-out by SQUIDs with 40 channel frequency domain multiplexing. Refractive optical elements are made with high purity alumina to achieve high optical throughput. The receiver is designed to achieve noise equivalent temperature of 5.8~$\mu$K$_{CMB}\sqrt{s}$ in each frequency band. \Pb-2 will deploy in 2016 in the Atacama desert in Chile. The Simons Array is a project to further increase sensitivity by deploying three \Pb-2 type receivers. The Simons Array will cover 95~GHz, 150~GHz and 220~GHz frequency bands for foreground control. The Simons Array will be able to constrain tensor-to-scalar ratio and sum of neutrino masses to $\sigma(r) = 6\times 10^{-3}$ at $r = 0.1$ and $\sum m_\nu (\sigma =1)$ to 40 meV.

[33]  http://arxiv.org/abs/1501.07911v2 [ html pdf ]
Modeling atmospheric emission for CMB ground-based observations
J. Errard, P. A. R. Ade, Y. Akiba, K. Arnold, M. Atlas, C. Baccigalupi, D. Barron, D. Boettger, J. Borrill, S. Chapman, Y. Chinone, A. Cukierman, J. Delabrouille, M. Dobbs, A. Ducout, T. Elleflot, G. Fabbian, C. Feng, S. Feeney, A. Gilbert, N. Goeckner-Wald, N. W. Halverson, M. Hasegawa, K. Hattori, M. Hazumi, C. Hill, W. L. Holzapfel, Y. Hori, Y. Inoue, G. C. Jaehnig, A. H. Jaffe, O. Jeong, N. Katayama, J. Kaufman, B. Keating, Z. Kermish, R. Keskitalo, T. Kisner, M. Le Jeune, A. T. Lee, E. M. Leitch, D. Leon, E. Linder, F. Matsuda, T. Matsumura, N. J. Miller, M. J. Myers, M. Navaroli, H. Nishino, T. Okamura, H. Paar, J. Peloton, D. Poletti, G. Puglisi, G. Rebeiz, C. L. Reichardt, P. L. Richards, C. Ross, K. M. Rotermund, D. E. Schenck, B. D. Sherwin, P. Siritanasak, G. Smecher, N. Stebor, B. Steinbach, R. Stompor, A. Suzuki, O. Tajima, S. Takakura, A. Tikhomirov, T. Tomaru, N. Whitehorn, B. Wilson, A. Yadav, O. Zahn

Atmosphere is one of the most important noise sources for ground-based cosmic microwave background (CMB) experiments. By increasing optical loading on the detectors, it amplifies their effective noise, while its fluctuations introduce spatial and temporal correlations between detected signals. We present a physically motivated 3d-model of the atmosphere total intensity emission in the millimeter and sub-millimeter wavelengths. We derive a new analytical estimate for the correlation between detectors time-ordered data as a function of the instrument and survey design, as well as several atmospheric parameters such as wind, relative humidity, temperature and turbulence characteristics. Using an original numerical computation, we examine the effect of each physical parameter on the correlations in the time series of a given experiment. We then use a parametric-likelihood approach to validate the modeling and estimate atmosphere parameters from the POLARBEAR-I project first season data set. We derive a new 1.0% upper limit on the linear polarization fraction of atmospheric emission. We also compare our results to previous studies and weather station measurements. The proposed model can be used for realistic simulations of future ground-based CMB observations.

[34]  http://arxiv.org/abs/1506.01716v1 [ html pdf ]
Forecasting constraints from the cosmic microwave background on eternal inflation
Stephen M. Feeney, Franz Elsner, Matthew C. Johnson, Hiranya V. Peiris

We forecast the ability of cosmic microwave background (CMB) temperature and polarization datasets to constrain theories of eternal inflation using cosmic bubble collisions. Using the Fisher matrix formalism, we determine both the overall detectability of bubble collisions and the constraints achievable on the fundamental parameters describing the underlying theory. The CMB signatures considered are based on state-of-the-art numerical relativistic simulations of the bubble collision spacetime, evolved using the full temperature and polarization transfer functions. Comparing a theoretical cosmic-variance-limited experiment to the WMAP and Planck satellites, we find that there is no improvement to be gained from future temperature data, that adding polarization improves detectability by approximately 30%, and that cosmic-variance-limited polarization data offer only marginal improvements over Planck. The fundamental parameter constraints achievable depend on the precise values of the tensor-to-scalar ratio and energy density in (negative) spatial curvature. For a tensor-to-scalar ratio of $0.1$ and spatial curvature at the level of $10^{-4}$, using cosmic-variance-limited data it is possible to measure the width of the potential barrier separating the inflating false vacuum from the true vacuum down to $M_{\rm Pl}/500$, and the initial proper distance between colliding bubbles to a factor $\pi/2$ of the false vacuum horizon size (at three sigma). We conclude that very near-future data will have the final word on bubble collisions in the CMB.

[35]  http://arxiv.org/abs/1308.0602v3 [ html pdf ]
Sparse Inpainting and Isotropy
Stephen M. Feeney, Domenico Marinucci, Jason D. McEwen, Hiranya V. Peiris, Benjamin D. Wandelt, Valentina Cammarota

Sparse inpainting techniques are gaining in popularity as a tool for cosmological data analysis, in particular for handling data which present masked regions and missing observations. We investigate here the relationship between sparse inpainting techniques using the spherical harmonic basis as a dictionary and the isotropy properties of cosmological maps, as for instance those arising from cosmic microwave background (CMB) experiments. In particular, we investigate the possibility that inpainted maps may exhibit anisotropies in the behaviour of higher-order angular polyspectra. We provide analytic computations and simulations of inpainted maps for a Gaussian isotropic model of CMB data, suggesting that the resulting angular trispectrum may exhibit small but non-negligible deviations from isotropy.

[36]  http://arxiv.org/abs/1303.3409v2 [ html pdf ]
Bayesian analysis of anisotropic cosmologies: Bianchi VII_h and WMAP
J. D. McEwen, T. Josset, S. M. Feeney, H. V. Peiris, A. N. Lasenby

We perform a definitive analysis of Bianchi VII_h cosmologies with WMAP observations of the cosmic microwave background (CMB) temperature anisotropies. Bayesian analysis techniques are developed to study anisotropic cosmologies using full-sky and partial-sky, masked CMB temperature data. We apply these techniques to analyse the full-sky internal linear combination (ILC) map and a partial-sky, masked W-band map of WMAP 9-year observations. In addition to the physically motivated Bianchi VII_h model, we examine phenomenological models considered in previous studies, in which the Bianchi VII_h parameters are decoupled from the standard cosmological parameters. In the two phenomenological models considered, Bayes factors of 1.7 and 1.1 units of log-evidence favouring a Bianchi component are found in full-sky ILC data. The corresponding best-fit Bianchi maps recovered are similar for both phenomenological models and are very close to those found in previous studies using earlier WMAP data releases. However, no evidence for a phenomenological Bianchi component is found in the partial-sky W-band data. In the physical Bianchi VII_h model we find no evidence for a Bianchi component: WMAP data thus do not favour Bianchi VII_h cosmologies over the standard Lambda Cold Dark Matter (LCDM) cosmology. It is not possible to discount Bianchi VII_h cosmologies in favour of LCDM completely, but we are able to constrain the vorticity of physical Bianchi VII_h cosmologies at $(\omega/H)_0 < 8.6 \times 10^{-10}$ with 95% confidence.

[37]  http://arxiv.org/abs/1210.2725v3 [ html pdf ]
Hierarchical Bayesian Detection Algorithm for Early-Universe Relics in the Cosmic Microwave Background
Stephen M. Feeney, Matthew C. Johnson, Jason D. McEwen, Daniel J. Mortlock, Hiranya V. Peiris

A number of theoretically well-motivated additions to the standard cosmological model predict weak signatures in the form of spatially localized sources embedded in the cosmic microwave background (CMB) fluctuations. We present a hierarchical Bayesian statistical formalism and a complete data analysis pipeline for testing such scenarios. We derive an accurate approximation to the full posterior probability distribution over the parameters defining any theory that predicts sources embedded in the CMB, and perform an extensive set of tests in order to establish its validity. The approximation is implemented using a modular algorithm, designed to avoid a posteriori selection effects, which combines a candidate-detection stage with a full Bayesian model-selection and parameter-estimation analysis. We apply this pipeline to theories that predict cosmic textures and bubble collisions, extending previous analyses by using: (1) adaptive-resolution techniques, allowing us to probe features of arbitrary size, and (2) optimal filters, which provide the best possible sensitivity for detecting candidate signatures. We conclude that the WMAP 7-year data do not favor the addition of either cosmic textures or bubble collisions to the standard cosmological model, and place robust constraints on the predicted number of such sources. The expected numbers of bubble collisions and cosmic textures on the CMB sky within our detection thresholds are constrained to be fewer than 4.0 and 5.2 at 95% confidence, respectively.

[38]  http://arxiv.org/abs/1307.2904v2 [ html pdf ]
(Lack of) Cosmological evidence for dark radiation after Planck
Licia Verde, Stephen M. Feeney, Daniel J. Mortlock, Hiranya V. Peiris

We use Bayesian model comparison to determine whether extensions to Standard-Model neutrino physics -- primarily additional effective numbers of neutrinos and/or massive neutrinos -- are merited by the latest cosmological data. Given the significant advances in cosmic microwave background (CMB) observations represented by the Planck data, we examine whether Planck temperature and CMB lensing data, in combination with lower redshift data, have strengthened (or weakened) the previous findings. We conclude that the state-of-the-art cosmological data do not show evidence for deviations from the standard cosmological model (which has three massless neutrino families). This does not mean that the model is necessarily correct -- in fact we know it is incomplete as neutrinos are not massless -- but it does imply that deviations from the standard model (e.g., non-zero neutrino mass) are too small compared to the current experimental uncertainties to be inferred from cosmological data alone.

[39]  http://arxiv.org/abs/1302.0014v3 [ html pdf ]
Is there evidence for additional neutrino species from cosmology?
Stephen M. Feeney, Hiranya V. Peiris, Licia Verde

It has been suggested that recent cosmological and flavor-oscillation data favor the existence of additional neutrino species beyond the three predicted by the Standard Model of particle physics. We apply Bayesian model selection to determine whether there is indeed any evidence from current cosmological datasets for the standard cosmological model to be extended to include additional neutrino flavors. The datasets employed include cosmic microwave background temperature, polarization and lensing power spectra, and measurements of the baryon acoustic oscillation scale and the Hubble constant. We also consider other extensions to the standard neutrino model, such as massive neutrinos, and possible degeneracies with other cosmological parameters. The Bayesian evidence indicates that current cosmological data do not require any non-standard neutrino properties.

[40]  http://arxiv.org/abs/1303.5341v2 [ html pdf ]
The importance of local measurements for cosmology
Licia Verde, Raul Jimenez, Stephen Feeney

We explore how local, cosmology-independent measurements of the Hubble constant and the age of the Universe help to provide a powerful consistency check of the currently favored cosmological model (flat LambdaCDM) and model-independent constraints on cosmology. We use cosmic microwave background (CMB) data to define the model-dependent cosmological parameters, and add local measurements to assess consistency and determine whether extensions to the model are justified. At current precision, there is no significant tension between the locally measured Hubble constant and age of the Universe (with errors of 3% and 5% respectively) and the corresponding parameters derived from the CMB. However, if errors on the local measurements could be decreased by a factor of two, one could decisively conclude if there is tension or not. We also compare the local and CMB data assuming simple extensions of the flat, $\Lambda$CDM model (including curvature, dark energy with a constant equation of state parameter not equal to -1, non-zero neutrino masses and a non-standard number of neutrino families) and find no need for these extra parameters; in particular, we constrain the effective number of neutrino species to be Neff < 4 at 95% confidence. We show that local measurements provide constraints on the curvature and equation of state of dark energy nearly orthogonal to those of the CMB. We argue that cosmology-independent measurements of local quantities at the percent level would be very useful to explore cosmology in a model-independent way.

[41]  http://arxiv.org/abs/1206.5035v1 [ html pdf ]
Detecting candidate cosmic bubble collisions with optimal filters
J. D. McEwen, S. M. Feeney, M. C. Johnson, H. V. Peiris

We review an optimal-filter-based algorithm for detecting candidate sources of unknown and differing size embedded in a stochastic background, and its application to detecting candidate cosmic bubble collision signatures in Wilkinson Microwave Anisotropy Probe (WMAP) 7-year observations. The algorithm provides an enhancement in sensitivity over previous methods by a factor of approximately two. Moreover, it is optimal in the sense that no other filter-based approach can provide a superior enhancement of these signatures. Applying this algorithm to WMAP 7-year observations, eight new candidate bubble collision signatures are detected for follow-up analysis.

[42]  http://arxiv.org/abs/1203.1928v2 [ html pdf ]
A robust constraint on cosmic textures from the cosmic microwave background
Stephen M. Feeney, Matthew C. Johnson, Daniel J. Mortlock, Hiranya V. Peiris

Fluctuations in the cosmic microwave background (CMB) contain information which has been pivotal in establishing the current cosmological model. These data can also be used to test well-motivated additions to this model, such as cosmic textures. Textures are a type of topological defect that can be produced during a cosmological phase transition in the early universe, and which leave characteristic hot and cold spots in the CMB. We apply Bayesian methods to carry out a rigorous test of the texture hypothesis, using full-sky data from the Wilkinson Microwave Anisotropy Probe. We conclude that current data do not warrant augmenting the standard cosmological model with textures. We rule out at 95% confidence models that predict more than 6 detectable cosmic textures on the full sky.

[43]  http://arxiv.org/abs/1202.2861v2 [ html pdf ]
Optimal filters for detecting cosmic bubble collisions
J. D. McEwen, S. M. Feeney, M. C. Johnson, H. V. Peiris

A number of well-motivated extensions of the LCDM concordance cosmological model postulate the existence of a population of sources embedded in the cosmic microwave background (CMB). One such example is the signature of cosmic bubble collisions which arise in models of eternal inflation. The most unambiguous way to test these scenarios is to evaluate the full posterior probability distribution of the global parameters defining the theory; however, a direct evaluation is computationally impractical on large datasets, such as those obtained by the Wilkinson Microwave Anisotropy Probe (WMAP) and Planck. A method to approximate the full posterior has been developed recently, which requires as an input a set of candidate sources which are most likely to give the largest contribution to the likelihood. In this article, we present an improved algorithm for detecting candidate sources using optimal filters, and apply it to detect candidate bubble collision signatures in WMAP 7-year observations. We show both theoretically and through simulations that this algorithm provides an enhancement in sensitivity over previous methods by a factor of approximately two. Moreover, no other filter-based approach can provide a superior enhancement of these signatures. Applying our algorithm to WMAP 7-year observations, we detect eight new candidate bubble collision signatures for follow-up analysis.

[44]  http://arxiv.org/abs/1107.5466v2 [ html pdf ]
Avoiding bias in reconstructing the largest observable scales from partial-sky data
Stephen M. Feeney, Hiranya V. Peiris, Andrew Pontzen

Obscuration due to Galactic emission complicates the extraction of information from cosmological surveys, and requires some combination of the (typically imperfect) modeling and subtraction of foregrounds, or the removal of part of the sky. This particularly affects the extraction of information from the largest observable scales. Maximum-likelihood estimators for reconstructing the full-sky spherical harmonic coefficients from partial-sky maps have recently been shown to be susceptible to contamination from within the sky cut, arising due to the necessity to band-limit the data by smoothing prior to reconstruction. Using the WMAP 7-year data, we investigate modified implementations of such estimators which are robust to the leakage of contaminants from within masked regions. We provide a measure, based on the expected amplitude of residual foregrounds, for selecting the most appropriate estimator for the task at hand. We explain why the related quadratic maximum-likelihood estimator of the angular power spectrum does not suffer from smoothing-induced bias.

[45]  http://arxiv.org/abs/1012.1995v3 [ html pdf ]
First Observational Tests of Eternal Inflation
Stephen M. Feeney, Matthew C. Johnson, Daniel J. Mortlock, Hiranya V. Peiris

The eternal inflation scenario predicts that our observable universe resides inside a single bubble embedded in a vast inflating multiverse. We present the first observational tests of eternal inflation, performing a search for cosmological signatures of collisions with other bubble universes in cosmic microwave background data from the WMAP satellite. We conclude that the WMAP 7-year data do not warrant augmenting LCDM with bubble collisions, constraining the average number of detectable bubble collisions on the full sky to be less than 1.6 at 68% CL. Data from the Planck satellite can be used to more definitively test the bubble collision hypothesis.

[46]  http://arxiv.org/abs/1012.3667v2 [ html pdf ]
First Observational Tests of Eternal Inflation: Analysis Methods and WMAP 7-Year Results
Stephen M. Feeney, Matthew C. Johnson, Daniel J. Mortlock, Hiranya V. Peiris

In the picture of eternal inflation, our observable universe resides inside a single bubble nucleated from an inflating false vacuum. Many of the theories giving rise to eternal inflation predict that we have causal access to collisions with other bubble universes, providing an opportunity to confront these theories with observation. We present the results from the first observational search for the effects of bubble collisions, using cosmic microwave background data from the WMAP satellite. Our search targets a generic set of properties associated with a bubble collision spacetime, which we describe in detail. We use a modular algorithm that is designed to avoid a posteriori selection effects, automatically picking out the most promising signals, performing a search for causal boundaries, and conducting a full Bayesian parameter estimation and model selection analysis. We outline each component of this algorithm, describing its response to simulated CMB skies with and without bubble collisions. Comparing the results for simulated bubble collisions to the results from an analysis of the WMAP 7-year data, we rule out bubble collisions over a range of parameter space. Our model selection results based on WMAP 7-year data do not warrant augmenting LCDM with bubble collisions. Data from the Planck satellite can be used to more definitively test the bubble collision hypothesis.

[47]  http://arxiv.org/abs/astro-ph/0504236v1 [ html pdf ]
Automated Detection of Classical Novae with Neural Networks
S. Feeney, V. Belokurov, N. W. Evans, J. An, P. C. Hewett, M. Bode, M. Darnley, E. Kerins, P. Baillon, B. J. Carr, S. Paulin-Henriksson, A. Gould

The POINT-AGAPE collaboration surveyed M31 with the primary goal of optical detection of microlensing events, yet its data catalogue is also a prime source of lightcurves of variable and transient objects, including classical novae (CNe). A reliable means of identification, combined with a thorough survey of the variable objects in M31, provides an excellent opportunity to locate and study an entire galactic population of CNe. This paper presents a set of 440 neural networks, working in 44 committees, designed specifically to identify fast CNe. The networks are developed using training sets consisting of simulated novae and POINT-AGAPE lightcurves, in a novel variation on K-fold cross-validation. They use the binned, normalised power spectra of the lightcurves as input units. The networks successfully identify 9 of the 13 previously identified M31 CNe within their optimal working range (and 11 out of 13 if the network error bars are taken into account). They provide a catalogue of 19 new candidate fast CNe, of which 4 are strongly favoured.


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