Publications

2012
Ho S, Cuesta A, Seo H-J, de Putter R, Ross AJ, White M, Padmanabhan N, Saito S, Schlegel DJ, Schlafly E, et al. Clustering of Sloan Digital Sky Survey III Photometric Luminous Galaxies: The Measurement, Systematics, and Cosmological Implications. The Astrophysical Journal. 2012;761 :14. Publisher's VersionAbstract
The Sloan Digital Sky Survey (SDSS) surveyed 14,555 deg2, anddelivered over a trillion pixels of imaging data. We present a study ofgalaxy clustering using 900,000 luminous galaxies with photometricredshifts, spanning between z = 0.45 and z = 0.65, constructed from theSDSS using methods described in Ross et al. This data set spans 11,000deg2 and probes a volume of 3 h -3Gpc3, making it the largest volume ever used for galaxyclustering measurements. We describe in detail the construction of thesurvey window function and various systematics affecting ourmeasurement. With such a large volume, high-precision cosmologicalconstraints can be obtained given careful control and understanding ofthe observational systematics. We present a novel treatment of theobservational systematics and its applications to the clustering signalsfrom the data set. In this paper, we measure the angular clusteringusing an optimal quadratic estimator at four redshift slices with an
Ahn CP, Alexandroff R, Allende Prieto C, Anderson SF, Anderton T, Andrews BH, Aubourg É, Bailey S, Balbinot E, Barnes R, et al. The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey. The Astrophysical Journal Supplement Series. 2012;203 :21. Publisher's VersionAbstract
The Sloan Digital Sky Survey III (SDSS-III) presents the firstspectroscopic data from the Baryon Oscillation Spectroscopic Survey(BOSS). This ninth data release (DR9) of the SDSS project includes535,995 new galaxy spectra (median z ~ 0.52), 102,100 new quasar spectra(median z ~ 2.32), and 90,897 new stellar spectra, along with the datapresented in previous data releases. These spectra were obtained withthe new BOSS spectrograph and were taken between 2009 December and 2011July. In addition, the stellar parameters pipeline, which determinesradial velocities, surface temperatures, surface gravities, andmetallicities of stars, has been updated and refined with improvementsin temperature estimates for stars with T eff < 5000 K andin metallicity estimates for stars with [Fe/H] > -0.5. DR9 includesnew stellar parameters for all stars presented in DR8, including starsfrom SDSS-I and II, as well as those observed as part of the SEGUE-2.The astrometry error introduced in the DR8 imaging catalogs has beencorrected in the DR9 data products. The next data release for SDSS-IIIwill be in Summer 2013, which will present the first data from theAPOGEE along with another year of data from BOSS, followed by the finalSDSS-III data release in 2014 December.
Pâris I, Petitjean P, Aubourg É, Bailey S, Ross NP, Myers AD, Strauss MA, Anderson SF, Arnau E, Bautista J, et al. The Sloan Digital Sky Survey quasar catalog: ninth data release. Astronomy and Astrophysics. 2012;548 :66. Publisher's VersionAbstract
We present the Data Release 9 Quasar (DR9Q) catalog from the BaryonOscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky SurveyIII. The catalog includes all BOSS objects that were targeted as quasarcandidates during the survey, are spectrocopically confirmed as quasarsvia visual inspection, have luminosities Mi[z = 2] < -20.5(in a ΛCDM cosmology with H0 = 70 km s-1Mpc-1, ΩM = 0.3, andΩΛ = 0.7) and either display at least oneemission line with full width at half maximum (FWHM) larger than 500 kms-1 or, if not, have interesting/complex absorption features.It includes as well, known quasars (mostly from SDSS-I and II) that werereobserved by BOSS. This catalog contains 87 822 quasars (78 086 are newdiscoveries) detected over 3275 deg2 with robustidentification and redshift measured by a combination of principalcomponent eigenspectra newly derived from a training set of 8632 spectrafrom SDSS-DR7. The number of quasars with z > 2.15 (61 931) is ~2.8times larger than the number of z > 2.15 quasars previously known.Redshifts and FWHMs are provided for the strongest emission lines (C iv,C iii], Mg ii). The catalog identifies 7533 broad absorption linequasars and gives their characteristics. For each object the catalogpresents five-band (u, g, r, i, z) CCD-based photometry with typicalaccuracy of 0.03 mag, and information on the morphology and selectionmethod. The catalog also contains X-ray, ultraviolet, near-infrared, andradio emission properties of the quasars, when available, from otherlarge-area surveys. The calibrated digital spectra cover the wavelengthregion 3600-10 500 Å at a spectral resolution in the range 1300< R < 2500; the spectra can be retrieved from the SDSS CatalogArchive Server. We also provide a supplemental list of an additional 949quasars that have been identified, among galaxy targets of the BOSS oramong quasar targets after DR9 was frozen.Catalog is only available at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/548/A66
Anderson L, Aubourg E, Bailey S, Bizyaev D, Blanton M, Bolton AS, Brinkmann J, Brownstein JR, Burden A, Cuesta AJ, et al. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: baryon acoustic oscillations in the Data Release 9 spectroscopic galaxy sample. Monthly Notices of the Royal Astronomical Society. 2012;427 :3435-3467. Publisher's VersionAbstract
We present measurements of galaxy clustering from the Baryon OscillationSpectroscopic Survey (BOSS), which is part of the Sloan Digital SkySurvey III (SDSS-III). These use the Data Release 9 (DR9) CMASS sample,which contains 264 283 massive galaxies covering 3275 square degreeswith an effective redshift z = 0.57 and redshift range 0.43 < z <0.7. Assuming a concordance ΛCDM cosmological model, this samplecovers an effective volume of 2.2 Gpc3, and represents thelargest sample of the Universe ever surveyed at this density,n¯≈3×10-4 h-3 Mpc 3. We measure theangle-averaged galaxy correlation function and power spectrum, includingdensity-field reconstruction of the baryon acoustic oscillation (BAO)feature. The acoustic features are detected at a significance of5σ in both the correlation function and power spectrum. Combiningwith the SDSS-II luminous red galaxy sample, the detection significanceincreases to 6.7σ. Fitting for the position of the acousticfeatures measures the distance to z = 0.57 relative to the sound horizonDV/rs = 13.67 ± 0.22 at z = 0.57. Assuminga fiducial sound horizon of 153.19 Mpc, which matches cosmic microwavebackground constraints, this corresponds to a distance DV (z= 0.57) = 2094 ± 34 Mpc. At 1.7 per cent, this is the mostprecise distance constraint ever obtained from a galaxy survey. We placethis result alongside previous BAO measurements in a cosmologicaldistance ladder and find excellent agreement with the current supernovameasurements. We use these distance measurements to constrain variouscosmological models, finding continuing support for a flat Universe witha cosmological constant.
Brownstein JR, Bolton AS, Schlegel DJ, Eisenstein DJ, Kochanek CS, Connolly N, Maraston C, Pandey P, Seitz S, Wake DA, et al. The BOSS Emission-Line Lens Survey (BELLS). I. A Large Spectroscopically Selected Sample of Lens Galaxies at Redshift ~0.5. The Astrophysical Journal. 2012;744 :41. Publisher's VersionAbstract

We present a catalog of 25 definite and 11 probable strong galaxy-galaxygravitational lens systems with lens redshifts 0.4 <~ z <~ 0.7,discovered spectroscopically by the presence of higher-redshift emissionlines within the Baryon Oscillation Spectroscopic Survey (BOSS) ofluminous galaxies, and confirmed with high-resolution Hubble SpaceTelescope (HST) images of 44 candidates. Our survey extends themethodology of the Sloan Lens Advanced Camera for Surveys survey (SLACS)to higher redshift. We describe the details of the BOSS spectroscopiccandidate detections, our HST ACS image processing and analysis methods,and our strong gravitational lens modeling procedure. We report BOSSspectroscopic parameters and ACS photometric parameters for allcandidates, and mass-distribution parameters for the best-fit singularisothermal ellipsoid models of definite lenses. Our sample to date wasselected using only the first six months of BOSS survey-qualityspectroscopic data. The full five-year BOSS database should produce asample of several hundred strong galaxy-galaxy lenses and in combinationwith SLACS lenses at lower redshift, strongly constrain the redshiftevolution of the structure of elliptical, bulge-dominated galaxies as afunction of luminosity, stellar mass, and rest-frame color, therebyproviding a powerful test for competing theories of galaxy formation andevolution.Based on observations made with the NASA/ESA Hubble Space Telescope,obtained at the Space Telescope Science Institute, which is operated bythe Association of Universities for Research in Astronomy, Inc., underNASA contract NAS 5-26555. These observations are associated withprogram 12209. Based on spectroscopic data from the Baryon OscillationSpectroscopic Survey of the Sloan Digital Sky Survey III.

2011
Rujopakarn W, Rieke GH, Eisenstein DJ, Juneau S. Morphology and Size Differences Between Local and High-redshift Luminous Infrared Galaxies. The Astrophysical Journal. 2011;726 :93. Publisher's VersionAbstract

We show that the star-forming regions in high-redshift luminous andultraluminous infrared galaxies (LIRGs and ULIRGs) and submillimetergalaxies (SMGs) have similar physical scales to those in local normalstar-forming galaxies. To first order, their higher infrared (IR)luminosities result from higher luminosity surface density. We also finda good correlation between the IR luminosity and IR luminosity surfacedensity in starburst galaxies across over five orders of magnitude of IRluminosity from local normal galaxies to z ~ 2 SMGs. The intenselystar-forming regions of local ULIRGs are significantly smaller thanthose in their high-redshift counterparts and hence divergesignificantly from this correlation, indicating that the ULIRGs foundlocally are a different population from the high-redshift ULIRGs andSMGs. Based on this relationship, we suggest that luminosity surfacedensity should serve as a more accurate indicator for the IR emittingenvironment, and hence the observable properties, of star-forminggalaxies than their IR luminosity. We demonstrate this approach byshowing that ULIRGs at z ~ 1 and a lensed galaxy at z ~ 2.5 exhibitaromatic features agreeing with local LIRGs that are an order ofmagnitude less luminous, but have similar IR luminosity surface density.A consequence of this relationship is that the aromatic emissionstrength in star-forming galaxies will appear to increase at z>1 fora given IR luminosity compared to their local counterparts.

Zhu G, Blanton MR, Burles SM, Coil AL, Cool RJ, Eisenstein DJ, Moustakas J, Wong KC, Aird J. PRIMUS: Obscured Star Formation on the Red Sequence. The Astrophysical Journal. 2011;726 :110. Publisher's VersionAbstract

We quantify the fraction of galaxies at moderate redshifts (0.1 < z< 0.5) that appear red-and-dead in the optical, but in fact containobscured star formation detectable in the infrared (IR), with the PRIsmMUlti-object Survey (PRIMUS). PRIMUS has measured ~120,000 robust

Lee BL, Ge J, Fleming SW, Stassun KG, Gaudi SB, Barnes R, Mahadevan S, Eastman JD, Wright J, Siverd RJ, et al. MARVELS-1b: A Short-period, Brown Dwarf Desert Candidate from the SDSS-III Marvels Planet Search. The Astrophysical Journal. 2011;728 :32. Publisher's VersionAbstract

We present a new short-period brown dwarf (BD) candidate around the starTYC 1240-00945-1. This candidate was discovered in the first year of theMulti-object APO Radial Velocity Exoplanets Large-area Survey (MARVELS),which is part of the Sloan Digital Sky Survey (SDSS) III, and wedesignate the BD as MARVELS-1b. MARVELS uses the technique of dispersedfixed-delay interferometery to simultaneously obtain radial velocity(RV) measurements for 60 objects per field using a single, custom-builtinstrument that is fiber fed from the SDSS 2.5 m telescope. From our 20RV measurements spread over a ~370 day time baseline, we derive aKeplerian orbital fit with semi-amplitude K = 2.533 ± 0.025 kms-1, period P = 5.8953 ± 0.0004 days, and eccentricityconsistent with circular. Independent follow-up RV data confirm theorbit. Adopting a mass of 1.37 ± 0.11 M sun for theslightly evolved F9 host star, we infer that the companion has a minimummass of 28.0 ± 1.5 M Jup, a semimajor axis 0.071± 0.002 AU assuming an edge-on orbit, and is probably tidallysynchronized. We find no evidence for coherent intrinsic variability ofthe host star at the period of the companion at levels greater than afew millimagnitudes. The companion has an a priori transit probability

Wong KC, Blanton MR, Burles SM, Coil AL, Cool RJ, Eisenstein DJ, Moustakas J, Zhu G, Arnouts S. PRIMUS: Enhanced Specific Star Formation Rates in Close Galaxy Pairs. The Astrophysical Journal. 2011;728 :119. Publisher's VersionAbstract

Tidal interactions between galaxies can trigger star formation, whichcontributes to the global star formation rate (SFR) density of theuniverse and could be a factor in the transformation of blue,star-forming galaxies to red, quiescent galaxies over cosmic time. Weinvestigate tidally triggered star formation in isolated close galaxypairs drawn from the Prism Multi-Object Survey (PRIMUS), alow-dispersion prism redshift survey that has measured ~120,000 robustgalaxy redshifts over 9.1 deg2 out to z ~ 1. We select asample of galaxies in isolated galaxy pairs at redshifts 0.25 <= z<= 0.75, with no other objects within a projected separation of 300 h-1 kpc and Δz/(1 + z) = 0.01, and compare them to acontrol sample of isolated galaxies to test for systematic differencesin their rest-frame FUV - r and NUV - r colors as a proxy for relativespecific star formation rates (SSFRs). We find that galaxies inrp <= 50 h -1 kpc pairs have bluerdust-corrected UV - r colors on average than the control galaxies by-0.134 ± 0.045 mag in FUV - r and -0.075 ± 0.038 mag in

Hickox RC, Myers AD, Brodwin M, Alexander DM, Forman WR, Jones C, Murray SS, Brown MJI, Cool RJ, Kochanek CS, et al. Clustering of Obscured and Unobscured Quasars in the Boötes Field: Placing Rapidly Growing Black Holes in the Cosmic Web. The Astrophysical Journal. 2011;731 :117. Publisher's VersionAbstract

We present the first measurement of the spatial clustering ofmid-infrared-selected obscured and unobscured quasars, using a sample inthe redshift range 0.7 < z < 1.8 selected from the 9deg2 Boötes multiwavelength survey. Recently, theSpitzer Space Telescope and X-ray observations have revealed largepopulations of obscured quasars that have been inferred from models ofthe X-ray background and supermassive black hole evolution. To date,little is known about obscured quasar clustering, which allows us tomeasure the masses of their host dark matter halos and explore theirrole in the cosmic evolution of black holes and galaxies. In this study,we use a sample of 806 mid-infrared-selected quasars and ≈250,000galaxies to calculate the projected quasar-galaxy cross-correlationfunction wp (R). The observed clustering yieldscharacteristic dark matter halo masses of log(M halo [h-1 M sun]) = 12.7+0.4-0.6and 13.3+0.3-0.4 for unobscured quasars (QSO-1s)and obscured quasars (Obs-QSOs), respectively. The results for QSO-1sare in excellent agreement with previous measurements for opticallyselected quasars, while we conclude that the Obs-QSOs are at least asstrongly clustered as the QSO-1s. We test for the effects of photometricredshift errors on the optically faint Obs-QSOs, and find that ourmethod yields a robust lower limit on the clustering; photo-z errors maycause us to underestimate the clustering amplitude of the Obs-QSOs by at

Aihara H, Allende Prieto C, An D, Anderson SF, Aubourg É, Balbinot E, Beers TC, Berlind AA, Bickerton SJ, Bizyaev D, et al. The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III. The Astrophysical Journal Supplement Series. 2011;193 :29. Publisher's VersionAbstract

The Sloan Digital Sky Survey (SDSS) started a new phase in 2008 August,with new instrumentation and new surveys focused on Galactic structureand chemical evolution, measurements of the baryon oscillation featurein the clustering of galaxies and the quasar Lyα forest, and aradial velocity search for planets around ~8000 stars. This paperdescribes the first data release of SDSS-III (and the eighth countingfrom the beginning of the SDSS). The release includes five-band imagingof roughly 5200 deg2 in the southern Galactic cap, bringingthe total footprint of the SDSS imaging to 14,555 deg2, orover a third of the Celestial Sphere. All the imaging data have beenreprocessed with an improved sky-subtraction algorithm and a final,self-consistent photometric recalibration and flat-field determination.This release also includes all data from the second phase of the SloanExtension for Galactic Understanding and Exploration (SEGUE-2),consisting of spectroscopy of approximately 118,000 stars at both highand low Galactic latitudes. All the more than half a million stellarspectra obtained with the SDSS spectrograph have been reprocessedthrough an improved stellar parameter pipeline, which has betterdetermination of metallicity for high-metallicity stars.

Mehta KT, Seo H-J, Eckel J, Eisenstein DJ, Metchnik M, Pinto P, Xu X. Galaxy Bias and Its Effects on the Baryon Acoustic Oscillation Measurements. The Astrophysical Journal. 2011;734 :94. Publisher's VersionAbstract

The baryon acoustic oscillation (BAO) feature in the clustering ofmatter in the universe serves as a robust standard ruler and hence canbe used to map the expansion history of the universe. We use high forceresolution simulations to analyze the effects of galaxy bias on themeasurements of the BAO signal. We apply a variety of Halo OccupationDistributions (HODs) and produce biased mass tracers to mimic differentgalaxy populations. We investigate whether galaxy bias changes thenonlinear shifts on the acoustic scale relative to the underlying darkmatter distribution presented by Seo et al. For the less biased HODmodels (b < 3), we do not detect any shift in the acoustic scale

Yang Y, Zabludoff A, Jahnke K, Eisenstein D, Davé R, Shectman SA, Kelson DD. Gas Kinematics in Lyα Nebulae. The Astrophysical Journal. 2011;735 :87. Publisher's VersionAbstract

Exploring the origin of Lyα nebulae ("blobs") at high redshiftrequires measurements of their gas kinematics that are impossible withonly the resonant, optically thick Lyα line. To define gas motionsrelative to the systemic velocity of the blob, the Lyα line mustbe compared with an optically thin line like Hα λ6563,which is not much altered by radiative transfer effects and is moreconcentrated about the galaxies embedded in the nebula's core. We obtainoptical and near-IR (NIR) spectra of the two brightest Lyα blobs(CDFS-LAB01 and CDFS-LAB02) from the Yang et al. sample using theMagellan/Magellan Echellette Spectrograph optical and Very LargeTelescope/SINFONI NIR spectrographs. Both the Lyα and Hαlines confirm that these blobs lie at the survey redshift, z ~ 2.3.Within each blob, we detect several Hα sources, which roughlycorrespond to galaxies seen in Hubble Space Telescope rest-frame UVimages. The Hα detections show that these galaxies have largeinternal velocity dispersions (σ v = 130-190 kms-1) and that, in the one system (LAB01), where we canreliably extract profiles for two Hα sources, their velocitydifference is Δv ~ 440 km s-1. The presence of multiplegalaxies within the blobs, and those galaxies' large velocitydispersions and large relative motion, is consistent with our previousfinding that Lyα blobs inhabit massive dark matter halos that willevolve into those typical of present-day rich clusters and that theembedded galaxies may eventually become brightest cluster galaxies. Todetermine whether the gas near the embedded galaxies is predominantlyinfalling or outflowing, we compare the Lyα and Hα linecenters, finding that Lyα is not offset (ΔvLyα = +0 km s-1) in LAB01 and redshifted byonly +230 km s-1 in LAB02. These offsets are small comparedto those of Lyman break galaxies, which average +450 km s-1and extend to about +700 km s-1. In LAB02, we detect C IIλ1334 and Si II λ1526 absorption lines, whose bluewardshifts of ~200 km s-1 are consistent with the small outflowimplied by the redward shift of Lyα. We test and rule out thesimplest infall models and those outflow models with super/hyperwinds,which require large outflow velocities. Because of the unknown geometryof the gas distribution and the possibility of multiple sources ofLyα emission embedded in the blobs, a larger sample and moresophisticated models are required to test more complex or a wider rangeof infall and outflow scenarios.

Eisenstein DJ, Weinberg DH, Agol E, Aihara H, Allende Prieto C, Anderson SF, Arns JA, Aubourg É, Bailey S, Balbinot E, et al. SDSS-III: Massive Spectroscopic Surveys of the Distant Universe, the Milky Way, and Extra-Solar Planetary Systems. The Astronomical Journal. 2011;142 :72. Publisher's VersionAbstract

Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II),SDSS-III is a program of four spectroscopic surveys on three scientificthemes: dark energy and cosmological parameters, the history andstructure of the Milky Way, and the population of giant planets aroundother stars. In keeping with SDSS tradition, SDSS-III will provideregular public releases of all its data, beginning with SDSS DataRelease 8 (DR8), which was made public in 2011 January and includesSDSS-I and SDSS-II images and spectra reprocessed with the latestpipelines and calibrations produced for the SDSS-III investigations.This paper presents an overview of the four surveys that compriseSDSS-III. The Baryon Oscillation Spectroscopic Survey will measureredshifts of 1.5 million massive galaxies and Lyα forest spectraof 150,000 quasars, using the baryon acoustic oscillation feature oflarge-scale structure to obtain percent-level determinations of thedistance scale and Hubble expansion rate at z < 0.7 and at z ≈2.5. SEGUE-2, an already completed SDSS-III survey that is thecontinuation of the SDSS-II Sloan Extension for Galactic Understandingand Exploration (SEGUE), measured medium-resolution (R =λ/Δλ ≈ 1800) optical spectra of 118,000 stars ina variety of target categories, probing chemical evolution, stellarkinematics and substructure, and the mass profile of the dark matterhalo from the solar neighborhood to distances of 100 kpc. APOGEE, theApache Point Observatory Galactic Evolution Experiment, will obtainhigh-resolution (R ≈ 30,000), high signal-to-noise ratio (S/N >=100 per resolution element), H-band (1.51 μm < λ < 1.70μm) spectra of 105 evolved, late-type stars, measuringseparate abundances for ~15 elements per star and creating the firsthigh-precision spectroscopic survey of all Galactic stellar populations(bulge, bar, disks, halo) with a uniform set of stellar tracers andspectral diagnostics. The Multi-object APO Radial Velocity ExoplanetLarge-area Survey (MARVELS) will monitor radial velocities of more than8000 FGK stars with the sensitivity and cadence (10-40 m s-1,~24 visits per star) needed to detect giant planets with periods up totwo years, providing an unprecedented data set for understanding theformation and dynamical evolution of giant planet systems. As of 2011January, SDSS-III has obtained spectra of more than 240,000 galaxies,29,000 z >= 2.2 quasars, and 140,000 stars, including 74,000 velocitymeasurements of 2580 stars for MARVELS.

Slosar A, Font-Ribera A, Pieri MM, Rich J, Le Goff J-M, Aubourg É, Brinkmann J, Busca N, Carithers B, Charlassier R, et al. The Lyman-α forest in three dimensions: measurements of large scale flux correlations from BOSS 1st-year data. Journal of Cosmology and Astro-Particle Physics. 2011;09 :001. Publisher's VersionAbstract

Using a sample of approximately 14,000 z > 2.1 quasars observed inthe first year of the Baryon Oscillation Spectroscopic Survey (BOSS), wemeasure the three-dimensional correlation function of absorption in theLyman-α forest. The angle-averaged correlation function oftransmitted flux (F = e) is securely detected outto comoving separations of 60 h-1Mpc, the firstdetection of flux correlations across widely separated sightlines. Aquadrupole distortion of the redshift-space correlation function bypeculiar velocities, the signature of the gravitational instabilityorigin of structure in the Lyman-α forest, is also detected athigh significance. We obtain a good fit to the data assuming lineartheory redshift-space distortion and linear bias of the transmittedflux, relative to the matter fluctuations of a standard ΛCDMcosmological model (inflationary cold dark matter with a cosmological

Coil AL, Blanton MR, Burles SM, Cool RJ, Eisenstein DJ, Moustakas J, Wong KC, Zhu G, Aird J, Bernstein RA, et al. The PRIsm MUlti-object Survey (PRIMUS). I. Survey Overview and Characteristics. The Astrophysical Journal. 2011;741 :8. Publisher's VersionAbstract

We present the PRIsm MUlti-object Survey (PRIMUS), a spectroscopic faintgalaxy redshift survey to z ~ 1. PRIMUS uses a low-dispersion prism andslitmasks to observe ~2500 objects at once in a 0.18 deg2field of view, using the Inamori Magellan Areal Camera and Spectrographcamera on the Magellan I Baade 6.5 m telescope at Las CampanasObservatory. PRIMUS covers a total of 9.1 deg2 of sky to adepth of i AB ~ 23.5 in seven different deep,multi-wavelength fields that have coverage from the Galaxy EvolutionExplorer, Spitzer, and either XMM or Chandra, as well as multiple-bandoptical and near-IR coverage. PRIMUS includes ~130,000 robust redshiftsof unique objects with a redshift precision of σ z /(1+ z) ~ 0.005. The redshift distribution peaks at z ~ 0.6 and extends toz = 1.2 for galaxies and z = 5 for broad-line active galactic nuclei.The motivation, observational techniques, fields, target selection,slitmask design, and observations are presented here, with a briefsummary of the redshift precision; a forthcoming paper presents the datareduction, redshift fitting, redshift confidence, and surveycompleteness. PRIMUS is the largest faint galaxy survey undertaken to

Starikova S, Cool R, Eisenstein D, Forman W, Jones C, Hickox R, Kenter A, Kochanek C, Kravtsov A, Murray SS, et al. Constraining Halo Occupation Properties of X-Ray Active Galactic Nuclei Using Clustering of Chandra Sources in the Boötes Survey Region. The Astrophysical Journal. 2011;741 :15. Publisher's VersionAbstract

We present one of the most precise measurements to date of the spatialclustering of X-ray-selected active galactic nuclei (AGNs) using asample derived from the Chandra X-ray Observatory survey in theBoötes field. The real-space two-point correlation function over aredshift interval from z = 0.17 to z ~ 3 is well described by the powerlaw, ξ(r) = (r/r 0), for comovingseparations r <~ 20 h -1 Mpc. We find γ = 1.84± 0.12 and r 0 consistent with no redshift trendwithin the sample (varying between r 0 = 5.5 ± 0.6 h-1 Mpc for langzrang = 0.37 and r 0 = 6.9± 1.0 h -1 Mpc for langzrang = 1.28).Furthermore, we are able to measure the projections of the two-pointcorrelation function both on the sky plane and in the line of sight. Weuse these measurements to show that the Chandra/Boötes AGNs arepredominantly located at the centers of dark matter halos with circularvelocity v max > 320 km s-1 or M180 > 4.1 × 1012 h -1 Msun, and tend to avoid satellite galaxies in halos of this orhigher mass. The halo occupation properties inferred from the clusteringproperties of Chandra/Boötes AGNs—the mass scale of theparent dark matter halos, the lack of significant redshift evolution ofthe clustering length, and the low satellite fraction—are broadlyconsistent with the Hopkins et al. scenario of quasar activity triggeredby mergers of similarly sized galaxies.

2010
Percival WJ, Reid BA, Eisenstein DJ, Bahcall NA, Budavari T, Frieman JA, Fukugita M, Gunn JE, Ivezić Ž, Knapp GR, et al. Baryon acoustic oscillations in the Sloan Digital Sky Survey Data Release 7 galaxy sample. Monthly Notices of the Royal Astronomical Society. 2010;401 :2148-2168. Publisher's VersionAbstract

The spectroscopic Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7)galaxy sample represents the final set of galaxies observed using theoriginal SDSS target selection criteria. We analyse the clustering ofgalaxies within this sample, including both the luminous red galaxy andmain samples, and also include the 2-degree Field Galaxy Redshift Surveydata. In total, this sample comprises 893319 galaxies over9100deg2. Baryon acoustic oscillations (BAO) are observed inpower spectra measured for different slices in redshift; this allows usto constrain the distance-redshift relation at multiple epochs. Weachieve a distance measure at redshift z = 0.275, ofrs(zd)/DV(0.275) = 0.1390 +/- 0.0037(2.7 per cent accuracy), where rs(zd) is thecomoving sound horizon at the baryon-drag epoch, DV(z)≡ [(1 +z)2D2Acz/H(z)]1/3,DA(z) is the angular diameter distance and H(z) is the Hubbleparameter. We find an almost independent constraint on the ratio ofdistances DV(0.35)/DV(0.2) = 1.736 +/- 0.065,which is consistent at the 1.1σ level with the best-fittingΛ cold dark matter model obtained when combining our z = 0.275distance constraint with the Wilkinson Microwave Anisotropy Probe 5-year(WMAP5) data. The offset is similar to that found in previous analysesof the SDSS DR5 sample, but the discrepancy is now of lowersignificance, a change caused by a revised error analysis and a changein the methodology adopted, as well as the addition of more data. UsingWMAP5 constraints on Ωbh2 andΩch2, and combining our BAO distancemeasurements with those from the Union supernova sample, places a tightconstraint on Ωm = 0.286 +/- 0.018 and H0 =68.2 +/- 2.2kms-1Mpc-1 that is robust to allowingΩk ≠ 0 and w ≠ -1. This result is independent ofthe behaviour of dark energy at redshifts greater than those probed bythe BAO and supernova measurements. Combining these data sets with thefull WMAP5 likelihood constraints provides tight constraints on bothΩk = -0.006 +/- 0.008 and w = -0.97 +/- 0.10 for aconstant dark energy equation of state.

Reid BA, Percival WJ, Eisenstein DJ, Verde L, Spergel DN, Skibba RA, Bahcall NA, Budavari T, Frieman JA, Fukugita M, et al. Cosmological constraints from the clustering of the Sloan Digital Sky Survey DR7 luminous red galaxies. Monthly Notices of the Royal Astronomical Society. 2010;404 :60-85. Publisher's VersionAbstract

We present the power spectrum of the reconstructed halo density fieldderived from a sample of luminous red galaxies (LRGs) from the SloanDigital Sky Survey (SDSS) Seventh Data Release (DR7). The halo powerspectrum has a direct connection to the underlying dark matter power fork <= 0.2hMpc-1, well into the quasi-linear regime. Thisenables us to use a factor of ~8 more modes in the cosmological analysisthan an analysis with kmax = 0.1hMpc-1, as wasadopted in the SDSS team analysis of the DR4 LRG sample. The observedhalo power spectrum for 0.02 < k < 0.2hMpc-1 is wellfitted by our model: χ2 = 39.6 for 40 degrees of freedomfor the best-fitting Λ cold dark matter (ΛCDM) model. Wefind Ωmh2(ns/0.96)1.2= 0.141+0.010-0.012 for a power-law primordialpower spectrum with spectral index ns andΩbh2 = 0.02265 fixed, consistent with cosmicmicrowave background measurements. The halo power spectrum alsoconstrains the ratio of the comoving sound horizon at the baryon-dragepoch to an effective distance to z = 0.35:rs/DV(0.35) =0.1097+0.0039-0.0042. Combining the halo powerspectrum measurement with the Wilkinson Microwave Anisotropy Probe(WMAP) 5 year results, for the flat ΛCDM model we findΩm = 0.289 +/- 0.019 and H0 = 69.4 +/-1.6kms-1Mpc-1. Allowing for massive neutrinos inΛCDM, we find eV at the 95 per cent confidence level. If weinstead consider the effective number of relativistic speciesNeff as a free parameter, we find Neff =4.8+1.8-1.7. Combining also with the Kowalski etal. supernova sample, we find Ωtot = 1.011 +/- 0.009and w = -0.99 +/- 0.11 for an open cosmology with constant dark energyequation of state w. The power spectrum and a module to calculate thelikelihoods are publicly available athttp://lambda.gsfc.nasa.gov/toolbox/lrgdr/.

Schneider DP, Richards GT, Hall PB, Strauss MA, Anderson SF, Boroson TA, Ross NP, Shen Y, Brandt WN, Fan X, et al. The Sloan Digital Sky Survey Quasar Catalog. V. Seventh Data Release. The Astronomical Journal. 2010;139 :2360-2373. Publisher's VersionAbstract

We present the fifth edition of the Sloan Digital Sky Survey (SDSS)Quasar Catalog, which is based upon the SDSS Seventh Data Release. Thecatalog, which contains 105,783 spectroscopically confirmed quasars,represents the conclusion of the SDSS-I and SDSS-II quasar survey. Thecatalog consists of the SDSS objects that have luminosities larger thanMi = -22.0 (in a cosmology with H 0 = 70 kms-1 Mpc-1, Ω M = 0.3, andΩΛ = 0.7), have at least one emission line withFWHM larger than 1000 km s-1 or have interesting/complexabsorption features, are fainter than i ≈ 15.0, and have highlyreliable redshifts. The catalog covers an area of ≈9380deg2. The quasar redshifts range from 0.065 to 5.46, with amedian value of 1.49; the catalog includes 1248 quasars at redshiftsgreater than 4, of which 56 are at redshifts greater than 5. The catalogcontains 9210 quasars with i < 18; slightly over half of the entrieshave i < 19. For each object the catalog presents positions accurateto better than 0farcs1 rms per coordinate, five-band (ugriz) CCD-basedphotometry with typical accuracy of 0.03 mag, and information on themorphology and selection method. The catalog also contains radio,near-infrared, and X-ray emission properties of the quasars, whenavailable, from other large-area surveys. The calibrated digital spectracover the wavelength region 3800-9200 Å at a spectral resolutionof ~= 2000; the spectra can be retrieved from the SDSS public database

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