# Publications

2014
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.
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.
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.
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
Azadi M, Aird J, Coil A, Moustakas J, Mendez A, Blanton M, Cool R, Eisenstein D, Wong K, Zhu G. PRIMUS: The relationship between Star formation and AGN accretion. ArXiv e-prints [Internet]. 2014;1407 :1975. Publisher's VersionAbstract
We study the evidence for a symbiotic connection between active galacticnuclei (AGN) fueling and star formation by investigating therelationship between the X-ray luminosities of AGN and the starformation rates (SFRs) of their host galaxies. We identify a sample of309 AGN with X-ray luminosities $10^{41} 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 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. Hahn CH, Blanton MR, Moustakas J, Coil AL, Cool RJ, Eisenstein DJ, Skibba RA, Wong KC, Zhu G. PRIMUS: Effect of Galaxy Environment on the Quiescent Fraction Evolution at z < 0.8. ArXiv e-prints [Internet]. 2014;1412 :7162. Publisher's VersionAbstract We investigate the effects of galaxy environment on the evolution of thequiescent fraction ($f_\mathrm{Q}$) from z =0.8 to 0.0 usingspectroscopic redshifts and multi-wavelength imaging data from the PRIsmMUlti-object Survey (PRIMUS) and the Sloan Digitial Sky Survey (SDSS).Our stellar mass limited galaxy sample consists of ~14,000 PRIMUSgalaxies within z = 0.2-0.8 and ~64,000 SDSS galaxies within z =0.05-0.12. We classify the galaxies as quiescent or star-forming basedon an evolving specific star formation cut, and as low or high densityenvironments based on fixed cylindrical aperture environmentmeasurements on a volume-limited environment defining population. Forquiescent and star-forming galaxies in low or high density environments,we examine the evolution of their stellar mass function (SMF). Thenusing the SMFs we compute$f_\mathrm{Q}(M_{*})$and quantify itsevolution within our redshift range. We find that the quiescent fractionis higher at higher masses and in denser environments. The quiescentfraction rises with cosmic time for all masses and environments. At afiducial mass of$10^{10.5}M_\odot$, from z~0.7 to 0.1, the quiescent Tojeiro R, Ross AJ, Burden A, Samushia L, Manera M, Percival WJ, Beutler F, Cuesta AJ, Dawson K, Eisenstein DJ, 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. ArXiv e-prints [Internet]. 2014;1401 :1768. Publisher's VersionAbstract We present the distance measurement to z = 0.32 using the 11th datarelease of the Sloan Digital Sky Survey-III Baryon Acoustic OscillationSurvey (BOSS). We use 313,780 galaxies of the low-redshift (LOWZ) sampleover 7,341 square-degrees to compute$D_V = (1264 \pm
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: modeling of the luminosity and colour dependence in the Data Release 10. ArXiv e-prints [Internet]. 2014;1401 :3009. Publisher's VersionAbstract
We investigate the luminosity and colour dependence of clustering ofCMASS galaxies in the Sloan Digital Sky Survey-III Baryon OscillationSpectroscopic Survey Tenth Data Release. The halo occupationdistribution framework is adopted to model the projected two-pointcorrelation function measurements on small and intermediate scales (from$0.02$ to $60\,h^{-1}{\rm {Mpc}}$) and to interpret the observed trendsand infer the connection of galaxies to dark matter halos. We find thatluminous red galaxies reside in massive halos of mass$M{\sim}10^{13}$--$10^{14}\,h^{-1}{\rm M_\odot}$ and more luminousgalaxies are more clustered and hosted by more massive halos. The strongsmall-scale clustering requires a fraction of these galaxies to besatellites in massive halos, with the fraction at the level of 5--8 percent and decreasing with luminosity. The characteristic mass of a halohosting on average one satellite galaxy above a luminosity threshold isabout a factor $8.7$ larger than that of a halo hosting a central galaxyabove the same threshold. At a fixed luminosity, progressively reddergalaxies are more strongly clustered on small scales, which can beexplained by having a larger fraction of these galaxies in the form ofsatellites in massive halos. Our clustering measurements on scales below$0.4\,h^{-1}{\rm {Mpc}}$ allow us to study the small-scale spatialdistribution of satellites inside halos. While the clustering ofluminosity-threshold samples can be well described by aNavarro-Frenk-White (NFW) profile, that of the reddest galaxies prefersa steeper or more concentrated profile. Finally, we also use galaxysamples of constant number density at different redshifts to study theevolution of luminous galaxies, and find the clustering to be consistentwith passive evolution in the redshift range of $0.5 \lesssim z \lesssim0.6$.
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 :156. 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.
Percival WJ, Ross AJ, Sánchez AG, Samushia L, Burden A, Crittenden R, Cuesta AJ, Magana MV, Manera M, Beutler F, et al. The clustering of Galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: including covariance matrix errors. Monthly Notices of the Royal Astronomical Society [Internet]. 2014 :244. Publisher's VersionAbstract
We present improved methodology for including covariance matrices in theerror budget of Baryon Oscillation Spectroscopic Survey (BOSS) galaxyclustering measurements, revisiting Data Release 9 (DR9) analyses, anddescribing a method that is used in DR10/11 analyses presented incompanion papers. The precise analysis method adopted is becomingincreasingly important, due to the precision that BOSS can now reach:even using as many as 600 mock catalogues to estimate covariance oftwo-point clustering measurements can still lead to an increase in theerrors of ˜20 per cent, depending on how the cosmologicalparameters of interest are measured. In this paper, we extend previouswork on this contribution to the error budget, deriving formulae forerrors measured by integrating over the likelihood, and to thedistribution of recovered best-fitting parameters fitting thesimulations also used to estimate the covariance matrix. Both aresituations that previous analyses of BOSS have considered. We apply theformulae derived to baryon acoustic oscillation (BAO) and redshift-spacedistortion (RSD) measurements from BOSS in our companion papers. Tofurther aid these analyses, we consider the optimum number of bins touse for two-point measurements using the monopole power spectrum orcorrelation function for BAO, and the monopole and quadrupole moments ofthe correlation function for anisotropic-BAO and RSD measurements.
Ross AJ, Samushia L, Burden A, Percival WJ, Tojeiro R, Manera M, Beutler F, Brinkmann J, Brownstein JR, Carnero A, et al. The clustering of galaxies in the SDSS-III DR10 Baryon Oscillation Spectroscopic Survey: no detectable colour dependence of distance scale or growth rate measurements. Monthly Notices of the Royal Astronomical Society [Internet]. 2014;437 :1109-1126. Publisher's VersionAbstract
We study the clustering of galaxies, as a function of their colour, fromData Release Ten (DR10) of the Sloan Digital Sky Survey III (SDSS-III)Baryon Oscillation Spectroscopic Survey. DR10 contains 540 505 galaxieswith 0.43 < z < 0.7; from these we select 122 967 for a Blue'sample and 131 969 for a Red' sample based on k + e corrected (to z =0.55) r - i colours and i-band magnitudes. The samples are chosen suchthat both contain more than 100 000 galaxies, have similar redshiftdistributions and maximize the difference in clustering amplitude. TheRed sample has a 40 per cent larger bias than the Blue(bRed/bBlue = 1.39 ± 0.04), implying thatthe Red galaxies occupy dark matter haloes with an average mass that is0.5 log10 M greater. Spherically averagedmeasurements of the correlation function, ξ0, and thepower spectrum are used to locate the position of the baryon acousticoscillation (BAO) feature of both samples. Using ξ0, weobtain distance scales, relative to the distance of our referenceΛ cold dark matter cosmology, of 1.010 ± 0.027 for the Redsample and 1.005 ± 0.031 for the Blue. After applyingreconstruction, these measurements improve to 1.013 ± 0.020 forthe Red sample and 1.008 ± 0.026 for the Blue. For each sample,measurements of ξ0 and the second multipole moment,ξ2, of the anisotropic correlation function are used todetermine the rate of structure growth, parametrized byfσ8. We find fσ8, Red = 0.511 ±0.083, fσ8, Blue = 0.509 ± 0.085 andfσ8, Cross = 0.423 ± 0.061 (from thecross-correlation between the Red and Blue samples). We use thecovariance between the bias and growth measurements obtained from eachsample and their cross-correlation to produce an optimally combinedmeasurement of fσ8, comb = 0.443 ± 0.055. Thisresult compares favourably to that of the full 0.43 < z < 0.7sample (fσ8, full = 0.422 ± 0.051) despite thefact that, in total, we use less than half of the number of galaxiesanalysed in the full sample measurement. In no instance do we detectsignificant differences in distance scale or structure growthmeasurements obtained from the Blue and Red samples. Our results areconsistent with theoretical predictions and our tests on mock samples,which predict that any colour-dependent systematic uncertainty on themeasured BAO position is less than 0.5 per cent.
2013
Majewski SR, Hasselquist S, Łokas EL, Nidever DL, Frinchaboy PM, García Pérez AE, Johnston KV, Mészáros S, Shetrone M, Allende Prieto C, et al. Discovery of a Dynamical Cold Point in the Heart of the Sagittarius dSph Galaxy with Observations from the APOGEE Project. The Astrophysical Journal Letters [Internet]. 2013;777 :L13. Publisher's VersionAbstract
The dynamics of the core of the Sagittarius (Sgr) dwarf spheroidal(dSph) galaxy are explored using high-resolution (R ~ 22, 500), H-band,near-infrared spectra of over 1000 giant stars in the central 3deg2 of the system, of which 328 are identified as Sgrmembers. These data, among some of the earliest observations from theSloan Digital Sky Survey III/Apache Point Observatory Galactic EvolutionExperiment (APOGEE) and the largest published sample of high resolutionSgr dSph spectra to date, reveal a distinct gradient in the velocitydispersion of Sgr from 11 to 14 km s-1 for radii>0.°8 from center to a dynamical cold point of 8 kms-1 in the Sgr center—a trend differing from thatfound in previous kinematical analyses of Sgr over larger scales thatsuggests a more or less flat dispersion profile at these radii.Well-fitting mass models with either cored and cusped dark matterdistributions can be found to match the kinematical results, althoughthe cored profile succeeds with significantly more isotropic stellarorbits than required for a cusped profile. It is unlikely that the coldpoint reflects an unusual mass distribution. The dispersion gradient mayarise from variations in the mixture of populations with distinctkinematics within the dSph; this explanation is suggested (e.g., bydetection of a metallicity gradient across similar radii), but notconfirmed, by the present data. Despite these remaining uncertaintiesabout their interpretation, these early test data (including some frominstrument commissioning) demonstrate APOGEE's usefulness for precisiondynamical studies, even for fields observed at extreme airmasses.
Kim A, Padmanabhan N, Aldering G, Allen S, Baltay C, Cahn R, D'Andrea C, Dalal N, Dawson K, Denney K, et al. Distance Probes of Dark Energy. ArXiv e-prints [Internet]. 2013;1309 :5382. 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.
Weinberg DH, Mortonson MJ, Eisenstein DJ, Hirata C, Riess AG, Rozo E. Observational probes of cosmic acceleration. Physics Reports [Internet]. 2013;530 :87-255. Publisher's VersionAbstract
The accelerating expansion of the universe is the most surprisingcosmological discovery in many decades, implying that the universe isdominated by some form of "dark energy" with exotic physical properties,or that Einstein's theory of gravity breaks down on cosmological scales.The profound implications of cosmic acceleration have inspired ambitiousefforts to understand its origin, with experiments that aim to measurethe history of expansion and growth of structure with percent-levelprecision or higher. We review in detail the four most well establishedmethods for making such measurements: Type Ia supernovae, baryonacoustic oscillations (BAO), weak gravitational lensing, and theabundance of galaxy clusters. We pay particular attention to thesystematic uncertainties in these techniques and to strategies forcontrolling them at the level needed to exploit "Stage IV" dark energyfacilities such as BigBOSS, LSST, Euclid, and WFIRST. We briefly reviewa number of other approaches including redshift-space distortions, theAlcock-Paczynski effect, and direct measurements of the Hubble constantH0. We present extensive forecasts for constraints on thedark energy equation of state and parameterized deviations from GeneralRelativity, achievable with Stage III and Stage IV experimental programsthat incorporate supernovae, BAO, weak lensing, and cosmic microwavebackground data. We also show the level of precision required forclusters or other methods to provide constraints competitive with thoseof these fiducial programs. We emphasize the value of a balanced programthat employs several of the most powerful methods in combination, bothto cross-check systematic uncertainties and to take advantage ofcomplementary information. Surveys to probe cosmic acceleration producedata sets that support a wide range of scientific investigations, andthey continue the longstanding astronomical tradition of mapping theuniverse in ever greater detail over ever larger scales.
Agarwal N, Ho S, Myers AD, Seo H-J, Ross AJ, Bahcall N, Brinkmann J, Eisenstein DJ, Muna D, Palanque-Delabrouille N, et al. Characterizing unknown systematics in large scale structure surveys. ArXiv e-prints [Internet]. 2013;1309 :2954. Publisher's VersionAbstract
Photometric large scale structure (LSS) surveys probe the largestvolumes in the Universe, but are inevitably limited by systematicuncertainties. Imperfect photometric calibration leads to biases in ourmeasurements of the density fields of LSS tracers such as galaxies andquasars, and as a result in cosmological parameter estimation. Earlierstudies have proposed using cross-correlations between differentredshift slices or cross-correlations between different surveys toreduce the effects of such systematics. In this paper we develop amethod to characterize unknown systematics. We demonstrate that while wedo not have sufficient information to correct for unknown systematics inthe data, we can obtain an estimate of their magnitude. We define aparameter to estimate contamination from unknown systematics usingcross-correlations between different redshift slices and proposediscarding bins in the angular power spectrum that lie outside a certaincontamination tolerance level. We show that this method improvesestimates of the bias using simulated data and further apply it tophotometric luminous red galaxies in the Sloan Digital Sky Survey as acase study.
Levi M, Bebek C, Beers T, Blum R, Cahn R, Eisenstein D, Flaugher B, Honscheid K, Kron R, Lahav O, et al. The DESI Experiment, a whitepaper for Snowmass 2013. ArXiv e-prints [Internet]. 2013;1308 :847. Publisher's VersionAbstract
The Dark Energy Spectroscopic Instrument (DESI) is a massivelymultiplexed fiber-fed spectrograph that will make the next major advancein dark energy in the timeframe 2018-2022. On the Mayall telescope, DESIwill obtain spectra and redshifts for at least 18 million emission-linegalaxies, 4 million luminous red galaxies and 3 million quasi-stellarobjects, in order to: probe the effects of dark energy on the expansionhistory using baryon acoustic oscillations (BAO), measure thegravitational growth history through redshift-space distortions, measurethe sum of neutrino masses, and investigate the signatures of primordialinflation. The resulting 3-D galaxy maps at z<2 and Lyman-alpha
Kim A, Padmanabhan N, Aldering G, Allen S, Baltay C, Cahn R, D'Andrea C, Dalal N, Dawson K, Denney K, et al. Distance Probes of Dark Energy. ArXiv e-prints [Internet]. 2013;1309 :5382. 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.