First BOSS Data: 3-D Map of 500,000 Galaxies, 100,000 Quasars |
The Third Sloan Digital Sky Survey (SDSS-III) has issued Data Release 9 (DR9), the first public release of data from the Baryon Oscillation Spectroscopic Survey (BOSS). In this release BOSS, the largest of SDSS-III’s four surveys, provides spectra for 535,995 newly observed galaxies, 102,100 quasars, and 116,474 stars, plus new information about objects in previous Sloan surveys (SDSS-I and II).
“This is just the first of three data releases from BOSS,” says David Schlegel of the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), an astrophysicist in the Lab’s Physics Division and BOSS’s principal investigator. “By the time BOSS is complete, we will have surveyed more of the sky, out to a distance twice as deep, for a volume more than five times greater than SDSS has surveyed before — a larger volume of the universe than all previous spectroscopic surveys combined.”
Spectroscopy yields a wealth of information about astronomical objects including their motion (called redshift and written “z”), their composition, and sometimes also the density of the gas and other material that lies between them and observers on Earth. The BOSS spectra are now freely available to a public that includes amateur astronomers, astronomy professionals who are not members of the SDSS-III collaboration, and high-school science teachers and their students.
The new release lists spectra for galaxies with redshifts up to z = 0.8 (roughly 7 billion light years away) and quasars with redshifts between z = 2.1 and 3.5 (from 10 to 11.5 billion light years away). When BOSS is complete it will have measured 1.5 million galaxies and at least 150,000 quasars, as well as many thousands of stars and other “ancillary” objects for scientific projects other than BOSS’s main goal. continue reading