Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2003 January 16
Explanation: In spiral galaxies, majestic winding arms of young stars and interstellar gas and dust rotate in a disk around a bulging galactic nucleus. Elliptical galaxies seem to be simpler, randomly swarming with old stars and lacking gas and dust. So astronomers were excited to find that NGC 1700, a young elliptical galaxy about 160 million light-years away, shows evidence for a 90,000 light-year wide rotating disk of multi-million degree hot gas. The evidence comes from data recorded by the orbiting Chandra Observatory, whose sharp x-ray image of NGC 1700 is seen above. Balancing gravity, the rotation of the x-ray hot disk, the largest of its type yet discovered, gives the galaxy a pronounced boxy profile in this false-colour picture. Theories about the origin of the disk suggest that NGC 1700 may be the result of a cosmic scale galactic merger, perhaps between a spiral and elliptical galaxy. NGC 1700 is just visible with small telescopes toward the flowing constellation Eridanus.
Authors & editors:
Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& NASA SEU Edu. Forum
& Michigan Tech. U.