Category Astronomy/Space

This is an artist’s conception of the “changing-look quasar” as is appared in early 2015. The glowing blue region shows the last of the gas being swallowed by central black hole as it shuts off. The spectrum is the previous one obtained by the SDSS in 2003. Credit: Dana Berry / SkyWorks Digital, Inc.

Astronomers have announced that a distant quasar ran out of gas. Their conclusions clarify why quasar SDSS J1011+5442 changed so dramatically in the handful of years between observations. “We are used to thinking of the sky as unchanging,” said University of Washington astronomy professor Scott Anderson. “The SDSS gives us a great opportunity to see that change as it happens.”

Quasars are the compact area at the center of large galaxies, usually surrounding a massive black hole...

Snapshot from a simulation of the first stars in the Universe, showing how the gas cloud might have become enriched with heavy elements. The image shows one of the first stars exploding, producing an expanding shell of gas (top) which enriches a nearby cloud, embedded inside a larger gas filament (centre). The image scale is 3,000 light years across, and the colourmap represents gas density, with red indicating higher density. Credit: Britton Smith, John Wise, Brian O’Shea, Michael Norman, and Sadegh Khochfar

Researchers have discovered a distant, ancient cloud of gas that may contain the signature of the very first stars that formed in the Universe...

These images of the Milky Way show the distribution of gas, at left, compared to the distribution of stars, at right, after the dwarf satellite disrupts the galaxy. Credit: Sukanya Chakrabarti/Rochester Institute of Technology

A trio of brightly pulsating stars at the outskirts of the Milky Way is racing away from the galaxy and may confirm a method for detecting dwarf galaxies dominated by dark matter and explain ripples in the outer disk of the galaxy. This new method to characterize dark matter marks the first real application of galactoseismology. Just as seismologists analyze waves to infer properties about Earth’s interior, Sukanya Chakrabarti, assistant professor at Rochester Institute of Technology, uses waves in the galactic disk to map the interior structure and mass of galaxies.