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TOPIC: Sloan Digital Sky Survey III
Blobrana


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RE: Sloan Digital Sky Survey III
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Astronomers Release the Largest Ever Three-Dimensional Map of the Sky

The Sloan Digital Sky Survey III (SDSS-III) has released the largest three-dimensional map of massive galaxies and distant black holes ever created. The new map pinpoints the locations and distances of over a million galaxies. It covers a total volume equivalent to that of a cube four billion light-years on a side.
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132,684-cluster catalogue
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 China reports biggest catalogue of galaxy clusters

Chinese astronomers say they have finished a new catalogue of more than 130,000 galaxy clusters, which makes it the biggest record of such cosmic phenomena.
The previously biggest catalogue, which contains 69,173 clusters, was published in 2011 by American scientists.
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Survey gets a grip on dark energy

Astronomers have measured the precise distance to over a quarter of a million galaxies to gain new insights into a key period in cosmic history.
The 3D map of the sky allows scientists to probe the time six billion years ago when dark energy became the dominant influence on the Universe's expansion.
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132,684-cluster catalogue
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Title: A catalogue of 132,684 clusters of galaxies identified from SDSS-III
Authors: Z. L. Wen, J. L. Han, F. S. Liu

Using the photometric redshifts of galaxies from the Sloan Digital Sky Survey III (SDSS-III), we identify 132,684 clusters in the redshift range of 0.05<z<0.8. Monte Carlo simulations show that the false detection rate is less than 6% for the whole sample. The completeness is more than 95% for clusters with a mass of M_{200}>1.0*10^{14} solar masses in the redshift range of 0.05<z<0.42, while clusters of z>0.42 are less complete and have a biased smaller richness than the real one due to incompleteness of member galaxies. We compare our sample with other cluster samples, and find that more than 90% of previously known rich clusters of 0.05<z<0.42 are matched with clusters in our sample. Richer clusters tend to have more luminous brightest cluster galaxies (BCGs). Correlating with X-ray and the Planck data, we show that the cluster richness is closely related to the X-ray luminosity, temperature and Sunyaev-Zel'dovich measurements. Comparison of the BCGs with the SDSS luminous red galaxies (LRGs) sample shows that 25% of LRGs are BCGs of our clusters, and 36% of LRGs are cluster member galaxies. In our cluster sample, 66% of BCGs satisfy the colour cuts of the SDSS LRGs selection criteria.

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Blobrana


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RE: Sloan Digital Sky Survey III
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Title: Clustering of Sloan Digital Sky Survey III Photometric Luminous Galaxies: The Measurement, Systematics and Cosmological Implications
Authors: Shirley Ho, Antonio Cuesta, Hee-Jong Seo, Roland de Putter, Ashley J. Ross, Martin White, Nikhil Padmanabhan, Shun Saito, David J. Schlegel, Eddie Schlafly, Uros Seljak, Carlos Hernandez-Monteagudo, Ariel G. Sanchez, Will J. Percival, Michael Blanton, Ramin Skibba, Don Schneider, Beth Reid, Olga Mena, Matteo Viel, Daniel J. Eisenstein, Francisco Prada, Benjamin Weaver, Neta Bahcall, Dimitry Bizyaev, Howard Brewinton, Jon Brinkman, Luiz Nicolaci da Costa, John R. Gott, Elena Malanushenko, Viktor Malanushenko, Bob Nichol, Daniel Oravetz, Kaike Pan, Nathalie Palanque-Delabrouille, Nicholas P Ross, Audrey Simmons, Fernando de Simoni, Stephanie Snedden, Christophe Yeche

The Sloan Digital Sky Survey (SDSS) surveyed 14,555 square degrees, and delivered over a trillion pixels of imaging data. We present a study of galaxy clustering using 900,000 luminous galaxies with photometric redshifts, spanning between z=0.45 and z=0.65, constructed from the SDSS using methods described in Ross et al. (2011). This data-set spans 11,000 square degrees and probes a volume of 3h^{-3} Gpc^3, making it the largest volume ever used for galaxy clustering measurements. We present a novel treatment of the observational systematics and its applications to the clustering signals from the data set. In this paper, we measure the angular clustering using an optimal quadratic estimator at 4 redshift slices with an accuracy of ~15% with bin size of delta_l = 10 on scales of the Baryon Acoustic Oscillations (BAO) (at l~40-400). We derive cosmological constraints using the full-shape of the power-spectra. For a flat Lambda CDM model, when combined with Cosmic Microwave Background Wilkinson Microwave Anisotropy Probe 7 (WMAP7) and H_0 constraints from 600 Cepheids observed by HST, we find \Omega_\Lambda = 0.73 ±0.019 and H_0 to be 70.5 ±1.6 km/s/Mpc. For an open Lambda CDM model, when combined with WMAP7 + HST, we find \Omega_K = 0.0035 ±0.0054, improved over WMAP7+HST alone by 40%. For a wCDM model, when combined with WMAP7+HST+SN, we find w = -1.071 ±0.078, and H_0 to be 71.3 ±1.7 km/s/Mpc, which is competitive with the latest large scale structure constraints from large spectroscopic surveys such as SDSS Data Release 7 (DR7) (Reid et al. 2010, Percival et al. 2010, Montesano et al. 2011) and WiggleZ (Blake et al. 2011). The SDSS-III Data Release 8 (SDSS-III DR8) Angular Clustering Data allows a wide range of investigations into the cosmological model, cosmic expansion (via BAO), Gaussianity of initial conditions and neutrino masses.

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Baryon Oscillation Spectroscopic Survey
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Measuring the Distant Universe in 3-D

The biggest 3-D map of the distant universe ever made, using light from 14,000 quasars - supermassive black holes at the centers of galaxies many billions of light years away - has been constructed by scientists with the third Sloan Digital Sky Survey (SDSS-III).
The map is the first major result from the Baryon Oscillation Spectroscopic Survey (BOSS), SDSS-III's largest survey, whose principal investigator is David Schlegel of the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab). The huge new map was presented at the April meeting of the American Physical Society in Anaheim, CA, by Ane Slosar of Brookhaven National Laboratory.
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'Map of the universe' revealed

Astronomers have released the largest ever colour image of the whole sky, stitched together from seven million images each made of 125 million pixels.
Data from the Sloan Digital Sky Survey has already helped identify and describe nearly half a billion stars and galaxies.
The release of the image - so big it would require around 500,000 HD televisions to be displayed fully - will enable professional and amateur astronomers alike to study the sky from their own computers.
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SDSS-III
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Most detailed image of night sky unveiled

It would take 500,000 high-definition TVs to view it in its full glory. Astronomers have released the largest digital image of the night sky ever made, to be mined for future discoveries.
It is actually a collection of millions of images taken since 1998 with a 2.5-metre telescope at Apache Point Observatory in New Mexico. The project, called the Sloan Digital Sky Survey, is now in its third phase, called SDSS-III.
Altogether, the images in the newly released collection contain more than a trillion pixels of data, covering a third of the sky in great detail.



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Blobrana


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Astronomers Release the Largest Image of the Sky Ever Made

On Tuesday, January 11, at the 217th meeting of the American Astronomical Society in Seattle, WA, astronomers and physicists with the third Sloan Digital Sky Survey (SDSS-III) announced the release of the largest image of the sky yet made. In the following press release issued by the SDSS-III collaboration, cosmologist David Schlegel of Berkeley Lab's Physics Division, principal investigator of SDSS-III's Baryon Oscillation Spectroscopic Survey (BOSS), discusses future maps of the sky and the role the giant image has played in targeting over a million galaxies for BOSS's study of dark energy and the history of the expansion of the universe.



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Mapping 3D structure of Universe may shed new light on dark energy
Astronomers from the University of Arizona (UA) and 41 other institutions are beginning the most ambitious project yet to map the three-dimensional structure of the universe in a quest to understand dark energy.

"Making a three-dimensional map is essential to understanding why the universe is expanding at an ever-accelerating rate" - UA astronomy professor Daniel Eisenstein, director of the Sloan Digital Sky Survey III, known as SDSS-III, a collaboration of 350 scientists.

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