# Publications

2015
Kim AG, Padmanabhan N, Aldering G, Allen SW, Baltay C, Cahn RN, D'Andrea CB, Dalal N, Dawson KS, Denney KD, et al. Distance probes of dark energy. Astroparticle Physics [Internet]. 2015;63:2-22. Publisher's VersionAbstract
This document presents the results from the Distances subgroup of theCosmic Frontier Community Planning Study (Snowmass 2013). We summarizethe current state of the field as well as future prospects andchallenges. In addition to the established probes using Type Iasupernovae and baryon acoustic oscillations, we also considerprospective methods based on clusters, active galactic nuclei,gravitational wave sirens and strong lensing time delays.
Slepian Z, Eisenstein DJ. On the signature of the baryon-dark matter relative velocity in the two- and three-point galaxy correlation functions. Monthly Notices of the Royal Astronomical Society [Internet]. 2015;448:9-26. Publisher's VersionAbstract
We develop a configuration-space picture of the relative velocitybetween baryons and dark matter that clearly explains how it can shiftthe baryon acoustic oscillation (BAO) scale in the galaxy-galaxycorrelation function. The shift occurs because the relative velocity isnon-zero only within the sound horizon and thus adds to the correlationfunction asymmetrically about the BAO peak. We further show that inconfiguration space the relative velocity has a localized, distinctivesignature in the three-point galaxy correlation function (3PCF). Inparticular, we find that a multipole decomposition is a favourable wayto isolate the relative velocity in the 3PCF, and that there is a strongsignature in the l = 1 multipole for triangles with two sides around theBAO scale. Finally, we investigate a further compression of the 3PCF toa function of only one triangle side that preserves the localized natureof the relative velocity signature while also nicely separating linearfrom non-linear bias. We expect that this scheme will substantiallylessen the computational burden of finding the relative velocity in the3PCF. The relative velocity's 3PCF signature can be used to correct theshift induced in the galaxy-galaxy correlation function so that nosystematic error due to this effect is introduced into the BAO as usedfor precision cosmology.
Holtzman JA, Shetrone M, Johnson JA, Allende Prieto C, Anders F, Andrews B, Beers TC, Bizyaev D, Blanton MR, Bovy J, et al. Abundances, Stellar Parameters, and Spectra From the SDSS-III/APOGEE Survey. ArXiv e-prints [Internet]. 2015;1501:4110. Publisher's VersionAbstract
The SDSS-III/APOGEE survey operated from 2011-2014 using the APOGEEspectrograph, which collects high-resolution (R~22,500), near-IR(1.51-1.70 microns) spectra with a multiplexing (300 fiber-fed objects)capability. We describe the survey data products that are publiclyavailable, which include catalogs with radial velocity, stellarparameters, and 15 elemental abundances for over 150,000 stars, as wellas the more than 500,000 spectra from which these quantities arederived. Calibration relations for the stellar parameters (Teff, log g,[M/H], [alpha/M]) and abundances (C, N, O, Na, Mg, Al, Si, S, K, Ca, Ti,V, Mn, Fe, Ni) are presented and discussed. The internal scatter of theabundances within clusters indicates that abundance precision isgenerally between 0.05 and 0.09 dex across a broad temperature range;within more limited ranges and at high S/N, it is smaller for someelemental abundances. We assess the accuracy of the abundances usingcomparison of mean cluster metallicities with literature values, APOGEEobservations of the solar spectrum and of Arcturus, comparison ofindividual star abundances with other measurements, and consideration ofthe locus of derived parameters and abundances of the entire sample, andfind that it is challenging to determine the absolute abundance scale;external accuracy may be good to 0.1-0.2 dex. Uncertainties may belarger at cooler temperatures (Teff<4000K). Access to the public datarelease and data products is described, and some guidance for using thedata products is provided.
Alam S, Albareti FD, Allende Prieto C, Anders F, Anderson SF, Andrews BH, Armengaud E, Aubourg É, Bailey S, Bautista JE, et al. The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III. ArXiv e-prints [Internet]. 2015;1501:963. Publisher's VersionAbstract
The third generation of the Sloan Digital Sky Survey (SDSS-III) tookdata from 2008 to 2014 using the original SDSS wide-field imager, theoriginal and an upgraded multi-object fiber-fed optical spectrograph, anew near-infrared high-resolution spectrograph, and a novel opticalinterferometer. All the data from SDSS-III are now made public. Inparticular, this paper describes Data Release 11 (DR11) including alldata acquired through 2013 July, and Data Release 12 (DR12) adding dataacquired through 2014 July (including all data included in previous datareleases), marking the end of SDSS-III observing. Relative to ourprevious public release (DR10), DR12 adds one million new spectra ofgalaxies and quasars from the Baryon Oscillation Spectroscopic Survey(BOSS) over an additional 3000 sq. deg of sky, more than triples thenumber of H-band spectra of stars as part of the Apache PointObservatory (APO) Galactic Evolution Experiment (APOGEE), and includesrepeated accurate radial velocity measurements of 5500 stars from theMulti-Object APO Radial Velocity Exoplanet Large-area Survey (MARVELS).The APOGEE outputs now include measured abundances of 15 differentelements for each star. In total, SDSS-III added 5200 sq. deg of ugrizimaging; 155,520 spectra of 138,099 stars as part of the SloanExploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey;2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and247,216 stars over 9376 sq. deg; 618,080 APOGEE spectra of 156,593stars; and 197,040 MARVELS spectra of 5,513 stars. Since its first lightin 1998, SDSS has imaged over 1/3 the Celestial sphere in five bands andobtained over five million astronomical spectra.
Krolewski AG, Eisenstein DJ. Measuring the luminosity and virial black hole mass dependence of quasar-galaxy clustering at z ~ 0.8. ArXiv e-prints [Internet]. 2015;1501:3898. Publisher's VersionAbstract
We study the dependence of quasar clustering on quasar luminosity andblack hole mass by measuring the angular overdensity of photometricallyselected galaxies imaged by WISE about z $\sim$ 0.8 quasars from SDSS.By measuring the quasar-galaxy cross-correlation function and usingphotometrically selected galaxies, we achieve a higher density of tracerobjects and a more sensitive detection of clustering than measurementsof the quasar autocorrelation function. We test models of quasarformation and evolution by measuring the luminosity dependence ofclustering amplitude. We find a significant overdensity of WISE galaxiesabout z $\sim$ 0.8 quasars at 0.2--6.4 h$^{-1}$ Mpc in projectedcomoving separation. We find no appreciable increase in clusteringamplitude with quasar luminosity across a decade in luminosity, and apower-law fit between luminosity and clustering amplitude gives anexponent of $-$0.01 $\pm$ 0.06 (1 $\sigma$ errorbar). We also fail tofind a significant relationship between clustering amplitude and blackhole mass, although our dynamic range in true mass is suppressed due tothe large uncertainties in virial black hole mass estimates. Our resultsindicate that a small range in host dark matter halo mass maps to alarge range in quasar luminosity.
Shen Y, Brandt WN, Dawson KS, Hall PB, McGreer ID, Anderson SF, Chen Y, Denney KD, Eftekharzadeh S, Fan X, et al. The Sloan Digital Sky Survey Reverberation Mapping Project: Technical Overview. The Astrophysical Journal Supplement Series [Internet]. 2015;216:4. Publisher's VersionAbstract
The Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project isa dedicated multi-object RM experiment that has spectroscopicallymonitored a sample of 849 broad-line quasars in a single 7deg2 field with the SDSS-III Baryon Oscillation SpectroscopicSurvey spectrograph. The RM quasar sample is flux-limited to ipsf = 21.7 mag, and covers a redshift range of 0.1 < z< 4.5 without any other cuts on quasar properties. Opticalspectroscopy was performed during 2014 January-July dark/gray time, withan average cadence of ~4 days, totaling more than 30 epochs. Supportingphotometric monitoring in the g and i bands was conducted at multiplefacilities including the Canada-France-Hawaii Telescope (CFHT) and theSteward Observatory Bok telescope in 2014, with a cadence of ~2 days andcovering all lunar phases. The RM field (R.A., decl. = 14:14:49.00,+53:05:00.0) lies within the CFHT-LS W3 field, and coincides with thePan-STARRS 1 (PS1) Medium Deep Field MD07, with three prior years ofmulti-band PS1 light curves. The SDSS-RM six month baseline program aimsto detect time lags between the quasar continuum and broad line region(BLR) variability on timescales of up to several months (in the observed
Delubac T, Bautista JE, Busca NG, Rich J, Kirkby D, Bailey S, Font-Ribera A, Slosar A, Lee K-G, Pieri MM, et al. Baryon acoustic oscillations in the Lyα forest of BOSS DR11 quasars. Astronomy and Astrophysics [Internet]. 2015;574:59. Publisher's VersionAbstract
We report a detection of the baryon acousticoscillation (BAO) feature inthe flux-correlation function of the Lyα forest of high-redshiftquasars with a statistical significance of five standard deviations. Thestudy uses 137 562 quasars in the redshift range 2.1 ≤ z ≤ 3.5from the data release 11 (DR11) of the Baryon Oscillation SpectroscopicSurvey (BOSS) of SDSS-III. This sample contains three times the numberof quasars used in previous studies. The measured position of the BAOpeak determines the angular distance, DA(z = 2.34) andexpansion rate, H(z = 2.34), both on a scale set by the sound horizon atthe drag epoch, rd. We find DA/rd =11.28 ± 0.65(1σ)+2.8-1.2 (2σ)and DH/rd = 9.18 ± 0.28(1σ) ±0.6(2σ) where DH = c/H. The optimal combination,~DH0.7DA0.3/rd is
Kepler SO, Pelisoli I, Koester D, Ourique G, Kleinman SJ, Romero AD, Nitta A, Eisenstein DJ, Costa JES, Külebi B, et al. New white dwarf stars in the Sloan Digital Sky Survey Data Release 10. Monthly Notices of the Royal Astronomical Society [Internet]. 2015;446:4078-4087. Publisher's VersionAbstract
We report the discovery of 9088 new spectroscopically confirmed whitedwarfs and subdwarfs in the Sloan Digital Sky Survey Data Release 10. Weobtain Teff, log g and mass for hydrogen atmosphere whitedwarf stars (DAs) and helium atmosphere white dwarf stars (DBs), andestimate the calcium/helium abundances for the white dwarf stars withmetallic lines (DZs) and carbon/helium for carbon-dominated spectra DQs.We found 1 central star of a planetary nebula, 2 new oxygen spectra onhelium atmosphere white dwarfs, 71 DQs, 42 hot DO/PG1159s, 171 whitedwarf+main-sequence star binaries, 206 magnetic DAHs, 327continuum-dominated DCs, 397 metal-polluted white dwarfs, 450helium-dominated white dwarfs, 647 subdwarfs and 6887 newhydrogen-dominated white dwarf stars.
Bray AD, Eisenstein DJ, Skibba RA, Blanton MR, Coil AL, Cool RJ, Mendez AJ, Moustakas J, Zhu G. PRIMUS: The Effect of Physical Scale on the Luminosity-Dependence of Galaxy Clustering via Cross-Correlations. ArXiv e-prints [Internet]. 2015;1502:1348. Publisher's VersionAbstract
We report small-scale clustering measurements from the PRIMUSspectroscopic redshift survey as a function of color and luminosity. Wemeasure the real-space cross-correlations between 62,106 primarygalaxies with PRIMUS redshifts and a tracer population of 545,000photometric galaxies over redshifts from z=0.2 to z=1. We separately fita power-law model in redshift and luminosity to each of threeindependent color-selected samples of galaxies. We report clusteringamplitudes at fiducial values of z=0.5 and L=1.5 L*. The clustering ofthe red galaxies is ~3 times as strong as that of the blue galaxies and~1.5 as strong as that of the green galaxies. We also find that theluminosity dependence of the clustering is strongly dependent onphysical scale, with greater luminosity dependence being found betweenr=0.0625 Mpc/h and r=0.25 Mpc/h, compared to the r=0.5 Mpc/h to r=2Mpc/h range. Moreover, over a range of two orders of magnitude inluminosity, a single power-law fit to the luminosity dependence is notsufficient to explain the increase in clustering at both the bright andfaint ends at the smaller scales. We argue that luminosity-dependentclustering at small scales is a necessary component of galaxy-halooccupation models for blue, star-forming galaxies as well as for red,quenched galaxies.
2014
Beutler F, Saito S, Seo H-J, Brinkmann J, Dawson KS, Eisenstein DJ, Font-Ribera A, Ho S, McBride CK, Montesano F, et al. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: testing gravity with redshift space distortions using the power spectrum multipoles. Monthly Notices of the Royal Astronomical Society [Internet]. 2014;443:1065-1089. Publisher's VersionAbstract
We analyse the anisotropic clustering of the Baryon OscillationSpectroscopic Survey (BOSS) CMASS Data Release 11 (DR11) sample, whichconsists of 690 827 galaxies in the redshift range 0.43 < z < 0.7and has a sky coverage of 8498 deg2. We perform our analysisin Fourier space using a power spectrum estimator suggested by Yamamotoet al. We measure the multipole power spectra in a self-consistentmanner for the first time in the sense that we provide a proper way totreat the survey window function and the integral constraint, withoutthe commonly used assumption of an isotropic power spectrum and withoutthe need to split the survey into subregions. The main cosmologicalsignals exploited in our analysis are the baryon acoustic oscillationsand the signal of redshift space distortions, both of which aredistorted by the Alcock-Paczynski effect. Together, these signals allowus to constrain the distance ratioDV(zeff)/rs(zd) = 13.89± 0.18, the Alcock-Paczynski parameterFAP(zeff) = 0.679 ± 0.031 and the growthrate of structure f(zeff)σ8(zeff) = 0.419 ±0.044 at the effective redshift zeff = 0.57. We emphasizethat our constraints are robust against possible systematicuncertainties. In order to ensure this, we perform a detailedsystematics study against CMASS mock galaxy catalogues and N-bodysimulations. We find that such systematics will lead to 3.1 per centuncertainty for fσ8 if we limit our fitting range to k= 0.01-0.20 h Mpc-1, where the statistical uncertainty isexpected to be three times larger. We did not find significantsystematic uncertainties for DV/rs orFAP. Combining our data set with Planck to test GeneralRelativity (GR) through the simple γ-parametrization, where thegrowth rate is given by f(z) = Ω ^{γ }_m(z), reveals a˜2σ tension between the data and the prediction by GR. Thetension between our result and GR can be traced back to a tension in theclustering amplitude σ8 between CMASS and Planck.
Montero-Dorta AD, Bolton AS, Brownstein JR, Swanson M, Dawson K, Prada F, Eisenstein D, Maraston C, Thomas D, Comparat J, et al. The Redshift Evolution of the High-Mass End of the Red Sequence Luminosity Function from the SDSS-III/BOSS CMASS Sample. ArXiv e-prints [Internet]. 2014;1410:5854. Publisher's VersionAbstract
We present the redshift evolution of the high-mass end of the^{0.55}i-band Red Sequence Luminosity Function (RS LF) within theredshift range 0.52
Vargas-Magaña M, Ho S, Xu X, Sánchez AG, O'Connell R, Eisenstein DJ, Cuesta AJ, Percival WJ, Ross AJ, Aubourg E, et al. The clustering of Galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: potential systematics in fitting of baryon acoustic feature. Monthly Notices of the Royal Astronomical Society [Internet]. 2014;445:2-28. Publisher's VersionAbstract
Extraction of the Baryon Acoustic Oscillations (BAO) to per cent levelaccuracy is challenging and demands an understanding of many potentialsystematics to an accuracy well below 1 per cent, in order to ensurethat they do not combine significantly when compared to statisticalerror of the BAO measurement. Baryon Oscillation Spectroscopic Survey(BOSS) Data Release 11 (DR11) reaches a distance measurement with˜1 per cent statistical error and this prompts an extensive searchfor all possible sub-per cent level systematic errors which couldpreviously be safely ignored. In this paper, we analyse the potentialsystematics in BAO fitting methodology using mocks and data from BOSSDR10 and DR11. We demonstrate the robustness of the fiducial multipolefitting methodology to be at 0.1-0.2 per cent level with a wide range oftests in mock galaxy catalogues pre- and post-reconstruction. We alsofind the DR10 and DR11 data from BOSS to be robust against changes inmethodology at a similar level. This systematic error budget isincorporated into the BOSS DR10 and DR11 BAO measurements. Of the widerange of changes we have investigated, we find that when fittingpost-reconstructed data or mocks, the only change which has an effect>0.1 per cent on the best-fitting values of distance measurements isvarying the order of the polynomials to describe the broad-band terms(˜0.2 per cent). Finally, we compare an alternative methodologydenoted as Clustering Wedges with Multipoles, and find that it isconsistent with the standard approach.
Aubourg É, Bailey S, Bautista JE, Beutler F, Bhardwaj V, Bizyaev D, Blanton M, Blomqvist M, Bolton AS, Bovy J, et al. Cosmological implications of baryon acoustic oscillation (BAO) measurements. ArXiv e-prints [Internet]. 2014;1411:1074. Publisher's VersionAbstract
We derive constraints on cosmological parameters and tests of darkenergy models from the combination of baryon acoustic oscillation (BAO)measurements with cosmic microwave background (CMB) and Type Iasupernova (SN) data. We take advantage of high-precision BAOmeasurements from galaxy clustering and the Ly-alpha forest (LyaF) inthe BOSS survey of SDSS-III. BAO data alone yield a high confidencedetection of dark energy, and in combination with the CMB angularacoustic scale they further imply a nearly flat universe. Combining BAO
Slepian Z, Eisenstein D. On the signature of the baryon-dark matter relative velocity in the two and three-point galaxy correlation functions. ArXiv e-prints [Internet]. 2014;1411:4052. Publisher's VersionAbstract
We develop a configuration-space picture of the relative velocitybetween baryons and dark matter that clearly explains how it can shiftthe BAO scale in the galaxy-galaxy correlation function. The shiftoccurs because the relative velocity is non-zero only within the soundhorizon and thus adds to the correlation function asymmetrically aboutthe BAO peak. We further show that in configuration space the relativevelocity has a localized, distinctive signature in the three-pointgalaxy correlation function (3PCF). In particular, we find that amultipole decomposition is a favorable way to isolate the relativevelocity in the 3PCF, and that there is a strong signature in the l=1multipole for triangles with 2 sides around the BAO scale. Finally, weinvestigate a further compression of the 3PCF to a function of only onetriangle side that preserves the localized nature of the relativevelocity signature while also nicely separating linear from non-linearbias. We expect that this scheme will substantially lessen thecomputational burden of finding the relative velocity in the 3PCF. Therelative velocity's 3PCF signature can be used to correct the shiftinduced in the galaxy-galaxy correlation function so that no systematicerror due to this effect is introduced into the BAO as used forprecision cosmology.
Font-Ribera A, Kirkby D, Busca N, Miralda-Escudé J, Ross NP, Slosar A, Rich J, Aubourg É, Bailey S, Bhardwaj V, et al. Quasar-Lyman α forest cross-correlation from BOSS DR11: Baryon Acoustic Oscillations. Journal of Cosmology and Astro-Particle Physics [Internet]. 2014;05:027. Publisher's VersionAbstract
We measure the large-scale cross-correlation of quasars with theLyα forest absorption, using over 164,000 quasars from DataRelease 11 of the SDSS-III Baryon Oscillation Spectroscopic Survey. Weextend the previous study of roughly 60,000 quasars from Data Release 9to larger separations, allowing a measurement of the Baryonic AcousticOscillation (BAO) scale along the line of sight c/(H(z =2.36)rs) = 9.0±0.3 and across the line of sightDA(z = 2.36)/rs = 10.8±0.4, consistent withCMB and other BAO data. Using the best fit value of the sound horizonfrom Planck data (rs = 147.49 Mpc), we can translate theseresults to a measurement of the Hubble parameter of H(z = 2.36) =226±8 km s-1 Mpc-1 and of theangular diameter distance of DA(z = 2.36) = 1590±60Mpc. The measured cross-correlation function and an update of the codeto fit the BAO scale (baofit) are made publicly available.
Tojeiro R, Ross AJ, Burden A, Samushia L, Manera M, Percival WJ, Beutler F, Brinkmann J, Brownstein JR, Cuesta AJ, et al. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: galaxy clustering measurements in the low-redshift sample of Data Release 11. Monthly Notices of the Royal Astronomical Society [Internet]. 2014;440:2222-2237. Publisher's VersionAbstract
We present the distance measurement to z = 0.32 using the eleventh datarelease (DR) of the Sloan Digital Sky Survey-III Baryon AcousticOscillation Survey (BOSS). We use 313 780 galaxies of the low-redshift(LOWZ) sample over 7341 square degrees to compute D_V=(1264 ± 25)(r_d/r_{d,fid}) - a sub 2 per cent measurement - using the baryonacoustic feature measured in the galaxy two-point correlation functionand power spectrum. We compare our results to those obtained in DR10. Westudy observational systematics in the LOWZ sample and quantifypotential effects due to photometric offsets between the northern andsouthern Galactic caps. We find the sample to be robust to allsystematic effects found to impact on the targeting of higher redshiftBOSS galaxies and that the observed north-south tensions can beexplained by either limitations in photometric calibration or by samplevariance, and have no impact on our final result. Our measurement,combined with the baryonic acoustic scale at z = 0.57, is used inAnderson et al. to constrain cosmological parameters.
Sánchez AG, Montesano F, Kazin EA, Aubourg E, Beutler F, Brinkmann J, Brownstein JR, Cuesta AJ, Dawson KS, Eisenstein DJ, et al. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological implications of the full shape of the clustering wedges in the data release 10 and 11 galaxy samples. Monthly Notices of the Royal Astronomical Society [Internet]. 2014;440:2692-2713. Publisher's VersionAbstract
We explore the cosmological implications of the angle-averagedcorrelation function, ξ(s), and the clustering wedges,ξ⊥(s) and ξ∥(s), of the LOWZ andCMASS galaxy samples from Data Releases 10 and 11 of the Sloan DigitalSky Survey III (SDSS-III) Baryon Oscillation Spectroscopic Survey. Ourresults show no significant evidence for a deviation from the standardΛ cold dark matter model. The combination of the information fromour clustering measurements with recent data from the cosmic microwavebackground is sufficient to constrain the curvature of the Universe toΩk = 0.0010 ± 0.0029, the total neutrino mass to∑mν < 0.23 eV (95 per cent confidence level), theeffective number of relativistic species to Neff = 3.31± 0.27 and the dark energy equation of state to wDE =-1.051 ± 0.076. These limits are further improved by addinginformation from Type Ia supernovae and baryon acoustic oscillationsfrom other samples. In particular, this data set combination iscompletely consistent with a time-independent dark energy equation ofstate, in which case we find wDE = -1.024 ± 0.052. Weexplore the constraints on the growth rate of cosmic structures assumingf(z) = Ωm(z)γ and obtain γ =0.69 ± 0.15, consistent with the predictions of generalrelativity of γ = 0.55.
Anderson L, Aubourg E, Bailey S, Beutler F, Bolton AS, Brinkmann J, Brownstein JR, Chuang C-H, Cuesta AJ, Dawson KS, et al. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: measuring DA and H at z = 0.57 from the baryon acoustic peak in the Data Release 9 spectroscopic Galaxy sample. Monthly Notices of the Royal Astronomical Society [Internet]. 2014;439:83-101. Publisher's VersionAbstract
We present measurements of the angular diameter distance to and Hubbleparameter at z = 0.57 from the measurement of the baryon acoustic peakin the correlation of galaxies from the Sloan Digital Sky Survey IIIBaryon Oscillation Spectroscopic Survey. Our analysis is based on asample from Data Release 9 of 264 283 galaxies over 3275 square degreesin the redshift range 0.43 < z < 0.70. We use two differentmethods to provide robust measurement of the acoustic peak positionacross and along the line of sight in order to measure the cosmologicaldistance scale. We find DA(0.57) = 1408 ± 45 Mpc andH(0.57) = 92.9 ± 7.8 km s-1 Mpc-1 for ourfiducial value of the sound horizon. These results from the anisotropicfitting are fully consistent with the analysis of the sphericallyaveraged acoustic peak position presented in Anderson et al. Ourdistance measurements are a close match to the predictions of thestandard cosmological model featuring a cosmological constant and zerospatial curvature.
Anderson L, Aubourg É, Bailey S, Beutler F, Bhardwaj V, Blanton M, Bolton AS, Brinkmann J, Brownstein JR, Burden A, et al. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: baryon acoustic oscillations in the Data Releases 10 and 11 Galaxy samples. Monthly Notices of the Royal Astronomical Society [Internet]. 2014;441:24-62. Publisher's VersionAbstract
We present a one per cent measurement of the cosmic distance scale fromthe detections of the baryon acoustic oscillations (BAO) in theclustering of galaxies from the Baryon Oscillation Spectroscopic Survey,which is part of the Sloan Digital Sky Survey III. Our results come fromthe Data Release 11 (DR11) sample, containing nearly one milliongalaxies and covering approximately 8500 square degrees and the redshiftrange 0.2 < z < 0.7. We also compare these results with those fromthe publicly released DR9 and DR10 samples. Assuming a concordanceΛ cold dark matter (ΛCDM) cosmological model, the DR11sample covers a volume of 13 Gpc3 and is the largest regionof the Universe ever surveyed at this density. We measure thecorrelation function and power spectrum, including density-fieldreconstruction of the BAO feature. The acoustic features are detected ata significance of over 7σ in both the correlation function andpower spectrum. Fitting for the position of the acoustic featuresmeasures the distance relative to the sound horizon at the drag epoch,rd, which has a value of rd,fid = 149.28 Mpc inour fiducial cosmology. We find DV = (1264 ± 25Mpc)(rd/rd,fid) at z = 0.32 and DV =(2056 ± 20 Mpc)(rd/rd,fid) at z = 0.57. At1.0 per cent, this latter measure is the most precise distanceconstraint ever obtained from a galaxy survey. Separating the clusteringalong and transverse to the line of sight yields measurements at z =0.57 of DA = (1421 ± 20Mpc)(rd/rd,fid) and H = (96.8 ± 3.4 kms-1 Mpc-1)(rd,fid/rd). Ourmeasurements of the distance scale are in good agreement with previousBAO measurements and with the predictions from cosmic microwavebackground data for a spatially flat CDM model with a cosmologicalconstant.
Guo H, Zheng Z, Zehavi I, Xu H, Eisenstein DJ, Weinberg DH, Bahcall NA, Berlind AA, Comparat J, McBride CK, et al. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: modelling of the luminosity and colour dependence in the Data Release 10. Monthly Notices of the Royal Astronomical Society [Internet]. 2014;441:2398-2413. Publisher's VersionAbstract
We investigate the luminosity and colour dependence of clustering ofCMASS galaxies in the Sloan Digital Sky Survey-III Baryon OscillationSpectroscopic Survey Data Release 10, focusing on projected correlationfunctions of well-defined samples extracted from the full catalogue of˜540 000 galaxies at z ˜ 0.5 covering about 6500deg2. The halo occupation distribution framework is adoptedto model the measurements on small and intermediate scales (from 0.02 to60 h-1 Mpc), infer the connection of galaxies to dark matterhaloes and interpret the observed trends. We find that luminous redgalaxies in CMASS reside in massive haloes of mass M ˜1013-1014 h-1 M⊙ andmore luminous galaxies are more clustered and hosted by more massivehaloes. The strong small-scale clustering requires a fraction of thesegalaxies to be satellites in massive haloes, with the fraction at thelevel of 5-8 per cent and decreasing with luminosity. The characteristicmass of a halo hosting on average one satellite galaxy above aluminosity threshold is about a factor of 8.7 larger than that of a halohosting a central galaxy above the same threshold. At a fixedluminosity, progressively redder galaxies are more strongly clustered onsmall scales, which can be explained by having a larger fraction ofthese galaxies in the form of satellites in massive haloes. Ourclustering measurements on scales below 0.4 h-1 Mpc allow usto study the small-scale spatial distribution of satellites insidehaloes. While the clustering of luminosity-threshold samples can be welldescribed by a Navarro-Frenk-White profile, that of the reddest galaxiesprefers a steeper or more concentrated profile. Finally, we also usegalaxy samples of constant number density at different redshifts tostudy the evolution of luminous red galaxies, and find the clustering tobe consistent with passive evolution in the redshift range of 0.5 ≲z ≲ 0.6.