Daniel J. Eisenstein

Texas Christian University, Fort Worth, Texas, United States

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Publications (428)1513.32 Total impact

  • Zachary Slepian · Daniel J. Eisenstein
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    ABSTRACT: Though Fourier transforms (FTs) are a common technique for finding correlation functions, they are not typically used in computations of the anisotropy of the two-point correlation function (2PCF) about the line of sight in wide-angle surveys because the line-of-sight direction is not constant on the Cartesian grid. Here we show how FTs can be used to compute the multipole moments of the anisotropic 2PCF. We also show how FTs can be used to accelerate the 3PCF algorithm of Slepian & Eisenstein. In both cases, these FT methods allow one to avoid the computational cost of pair counting, which scales as the square of the number density of objects in the survey. With the upcoming large data sets of Dark Energy Spectroscopic Instrument, Euclid, and Large Synoptic Survey Telescope, FT techniques will therefore offer an important complement to simple pair or triplet counts.
    No preview · Article · Jan 2016 · Monthly Notices of the Royal Astronomical Society Letters
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    ABSTRACT: We report a measurement of the large-scale 3-point correlation function of galaxies using the largest dataset for this purpose to date, 777, 202 Luminous Red Galaxies in the Sloan Digital Sky Survey Baryon Acoustic Oscillation Spectroscopic Survey (SDSS BOSS) DR12 CMASS sample. This work exploits the novel algorithm of Slepian & Eisenstein (2015b) to compute the multipole moments of the 3PCF in $\mathcal{O}(N^2)$ time, with $N$ the number of galaxies. Leading-order perturbation theory models the data well in a compressed basis where one triangle side is integrated out. We also present an accurate and computationally efficient means of estimating the covariance matrix. With these techniques the redshift-space linear and non-linear bias are measured, with 2.6% precision on the former if $\sigma_8$ is fixed. The data also indicates a $2.8\sigma$ preference for the BAO, confirming the presence of BAO in the 3-point function.
    Preview · Article · Dec 2015
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    ABSTRACT: Sound waves from the primordial fluctuations of the Universe imprinted in the large-scale structure, called baryon acoustic oscillations (BAOs), can be used as standard rulers to measure the scale of the Universe. These oscillations have already been detected in the distribution of galaxies. Here we propose to measure BAOs from the troughs (minima) of the density field. Based on two sets of accurate mock halo catalogues with and without BAOs in the seed initial conditions, we demonstrate that the BAO signal cannot be obtained from the clustering of classical disjoint voids, but is clearly detected from overlapping voids. The latter represent an estimate of all troughs of the density field. We compute them from the empty circumspheres centres constrained by tetrahedra of galaxies using Delaunay triangulation. Our theoretical models based on an unprecedented large set of detailed simulated void catalogues are remarkably well confirmed by observational data. We use the largest recently publicly available sample of Luminous Red Galaxies from SDSS-III BOSS DR11 to unveil for the first time a >3{\sigma} BAO detection from voids in observations. Since voids are nearly isotropically expanding regions, their centres represent the most quiet places in the Universe, keeping in memory the cosmos origin, and providing a new promising window in the analysis of the cosmological large-scale structure from galaxy surveys.
    No preview · Article · Nov 2015
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    ABSTRACT: We report the discovery of 6576 new spectroscopically confirmed white dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 12. We obtain Teff, log g and mass for hydrogen atmosphere white dwarf stars (DAs) and helium atmosphere white dwarf stars (DBs), estimate the calcium/helium abundances for the white dwarf stars with metallic lines (DZs) and carbon/helium for carbon-dominated spectra (DQs). We found one central star of a planetary nebula, one ultracompact helium binary (AM CVn), one oxygen line-dominated white dwarf, 15 hot DO/PG1159s, 12 new cataclysmic variables, 36 magnetic white dwarf stars, 54 DQs, 115 helium-dominated white dwarfs, 148 white dwarf + main-sequence star binaries, 236 metal-polluted white dwarfs, 300 continuum spectra DCs, 230 hot subdwarfs, 2936 new hydrogen-dominated white dwarf stars, and 2675 cool hydrogen-dominated subdwarf stars. We calculate the mass distribution of all 5883 DAs with S/N ≥ 15 in DR12, including the ones in DR7 and DR10, with an average S/N = 26, corrected to the 3D convection scale, and also the distribution after correcting for the observed volume, using 1/Vmax.
    Full-text · Article · Oct 2015 · Monthly Notices of the Royal Astronomical Society
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    ABSTRACT: The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has built the largest moderately high-resolution (R=22, 500) spectroscopic map of the stars across the Milky Way, and including dust-obscured areas. The APOGEE Stellar Parameter and Chemical Abundances Pipeline (ASPCAP) is the software developed for the automated analysis of these spectra. ASPCAP determines atmospheric parameters and chemical abundances from observed spectra by comparing observed spectra to libraries of theoretical spectra, using chi-2 minimization in a multidimensional parameter space. The package consists of a fortran90 code that does the actual minimization, and a wrapper IDL code for book-keeping and data handling. This paper explains in detail the ASPCAP components and functionality, and presents results from a number of tests designed to check its performance. ASPCAP provides stellar effective temperatures, surface gravities, and metallicities precise to 2%, 0.1 dex, and 0.05 dex, respectively, for most APOGEE stars, which are predominantly giants. It also provides abundances for up to 15 chemical elements with various levels of precision, typically under 0.1 dex. The final data release (DR12) of the Sloan Digital Sky Survey III contains an APOGEE database of more than 150,000 stars. ASPCAP development continues in the SDSS-IV APOGEE-2 survey.
    Full-text · Article · Oct 2015
  • Zachary Slepian · Daniel J. Eisenstein
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    ABSTRACT: The anisotropic 2-point correlation function (2PCF) of galaxies measures pairwise clustering as a function of the pair separation's angle to the line of sight. The latter is often defined as either the angle bisector of the observer-galaxy-pair triangle or the vector from the observer to the separation midpoint. Here we show how to accelerate either of these measurements with Fourier Transforms, using a slight generalization of the Yamamoto et al. (2006) estimator in which each member of the pair is used successively as the line of sight. We also present perturbation theory predictions for our generalized estimator including wide-angle corrections.
    No preview · Article · Oct 2015
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    ABSTRACT: We introduce a new method for estimating the covariance matrix for the galaxy correlation function in surveys of large-scale structure. Our method combines simple theoretical results with a realistic characterization of the survey to dramatically reduce noise in the covariance matrix. For example, with an investment of only ~1,000 CPU hours we can produce a model covariance matrix with noise levels that would otherwise require ~35,000 mocks. Non-Gaussian contributions to the model are calibrated against mock catalogs, after which the model covariance is found to be in impressive agreement with the mock covariance matrix. Since calibration of this method requires fewer mocks than brute force approaches, we believe that it could dramatically reduce the number of mocks required to analyse future surveys.
    No preview · Article · Oct 2015
  • Zachary Slepian · Daniel J. Eisenstein
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    ABSTRACT: In linear perturbation theory, all information about the growth of structure is contained in the Green's function, or equivalently, transfer function. These functions are generally computed using numerical codes or by phenomenological fitting formula anchored in accurate analytic results in the limits of large and small scale. Here we present a framework for analytically solving all scales, in particular the intermediate scales relevant for the baryon acoustic oscillations (BAO). We solve for the Green's function and transfer function using spherically-averaged overdensities and the approximation that the density of the coupled baryon-photon fluid is constant interior to the sound horizon.
    No preview · Article · Sep 2015 · Monthly Notices of the Royal Astronomical Society
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    ABSTRACT: The Baryon Oscillation Spectroscopic Survey (BOSS), part of the Sloan Digital Sky Survey (SDSS) III project, has provided the largest survey of galaxy redshifts available to date, in terms of both the number of galaxy redshifts measured by a single survey, and the effective cosmological volume covered. Key to analysing the clustering of these data to provide cosmological measurements is understanding the detailed properties of this sample. Potential issues include variations in the target catalogue caused by changes either in the targeting algorithm or properties of the data used, the pattern of spectroscopic observations, the spatial distribution of targets for which redshifts were not obtained, and variations in the target sky density due to observational systematics. We document here the target selection algorithms used to create the galaxy samples that comprise BOSS. We also present the algorithms used to create large-scale structure catalogues for the final Data Release (DR12) samples and the associated random catalogues that quantify the survey mask. The algorithms are an evolution of those used by the BOSS team to construct catalogues from earlier data, and have been designed to accurately quantify the galaxy sample. The code used, designated mksample, is released with this paper.
    Full-text · Article · Sep 2015 · Monthly Notices of the Royal Astronomical Society
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    ABSTRACT: We present distance scale measurements from the baryon acoustic oscillation signal in the CMASS and LOWZ samples from the Data Release 12 of the Baryon Oscillation Spectroscopic Survey (BOSS). The total volume probed is 14.5 Gpc$^3$, a 10% increment from Data Release 11. From an analysis of the spherically averaged correlation function, we infer a distance to $z=0.57$ of $D_V(z)r^{\rm fid}_{\rm d}/r_ {\rm d}=2028\pm19$ Mpc and a distance to $z=0.32$ of $D_V(z)r^{\rm fid}_{\rm d}/r_{\rm d}=1263\pm21$ Mpc assuming a cosmology in which $r^{\rm fid}_{\rm d}=147.10$ Mpc. From the anisotropic analysis, we find an angular diameter distance to $z=0.57$ of $D_{\rm A}(z)r^{\rm fid}_{\rm d}/r_{\rm d}=1401\pm19$ Mpc and a distance to $z=0.32$ of $981\pm20$ Mpc, a 1.4% and 2.0% measurement respectively. The Hubble parameter at $z=0.57$ is $H(z)r_{\rm d}/r^{\rm fid}_{\rm d}=100.3\pm3.4$ km s$^{-1}$ Mpc$^{-1}$ and its value at $z=0.32$ is $79.2\pm5.5$ km s$^{-1}$ Mpc$^{-1}$, a 3.4% and 6.9% measurement respectively. These cosmic distance scale constraints are in excellent agreement with a $\Lambda$CDM model with cosmological parameters released by the recent Planck 2015 results.
    No preview · Article · Sep 2015 · Monthly Notices of the Royal Astronomical Society
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    ABSTRACT: The Apache Point Observatory Galactic Evolution Experiment (APOGEE), one of the programs in the Sloan Digital Sky Survey III (SDSS-III), has now completed its systematic, homogeneous spectroscopic survey sampling all major populations of the Milky Way. After a three year observing campaign on the Sloan 2.5-m Telescope, APOGEE has collected a half million high resolution (R~22,500), high S/N (>100), infrared (1.51-1.70 microns) spectra for 146,000 stars, with time series information via repeat visits to most of these stars. This paper describes the motivations for the survey and its overall design---hardware, field placement, target selection, operations---and gives an overview of these aspects as well as the data reduction, analysis and products. An index is also given to the complement of technical papers that describe various critical survey components in detail. Finally, we discuss the achieved survey performance and illustrate the variety of potential uses of the data products by way of a number of science demonstrations, which span from time series analysis of stellar spectral variations and radial velocity variations from stellar companions, to spatial maps of kinematics, metallicity and abundance patterns across the Galaxy and as a function of age, to new views of the interstellar medium, the chemistry of star clusters, and the discovery of rare stellar species. As part of SDSS-III Data Release 12, all of the APOGEE data products are now publicly available.
    No preview · Article · Sep 2015
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    ABSTRACT: Comparisons between observational surveys and galaxy formation models find that dark matter haloes’ mass can largely explain their galaxies’ stellar mass. However, it remains uncertain whether additional environmental variables, known as assembly bias, are necessary to explain other galaxy properties. We use the Illustris simulation to investigate the role of assembly bias in producing galactic conformity by considering 18 000 galaxies with Mstellar > 2 × 109 M⊙. We find a significant signal of galactic conformity: out to distances of about 10 Mpc, the mean red fraction of galaxies around redder galaxies is higher than around bluer galaxies at fixed stellar mass. Dark matter haloes exhibit an analogous conformity signal, in which the fraction of haloes formed at earlier times (old haloes) is higher around old haloes than around younger ones at fixed halo mass. A plausible interpretation of galactic conformity is the combination of the halo conformity signal with the galaxy colour–halo age relation: at fixed stellar mass, particularly towards the low-mass end, Illustris’ galaxy colours correlate with halo age, with the reddest galaxies (often satellites) preferentially found in the oldest haloes. We explain the galactic conformity effect with a simple semi-empirical model, assigning stellar mass via halo mass (abundance matching) and galaxy colour via halo age (age matching). Regarding comparison to observations, we conclude that the adopted selection/isolation criteria, projection effects, and stacking techniques can have a significant impact on the measured amplitude of the conformity signal.
    Full-text · Article · Aug 2015 · Monthly Notices of the Royal Astronomical Society
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    ABSTRACT: The Extended Baryon Oscillation Spectroscopic Survey (eBOSS) will conduct novel cosmological observations using the BOSS spectrograph at Apache Point Observatory. Observations will be simultaneous with the Time Domain Spectroscopic Survey (TDSS) designed for variability studies and the Spectroscopic Identification of eROSITA Sources (SPIDERS) program designed for studies of X-ray sources. eBOSS will use four different tracers to measure the distance-redshift relation with baryon acoustic oscillations (BAO) in the clustering of matter. Using more than 250,000 new, spectroscopically confirmed luminous red galaxies at a median redshift z=0.72, we project that eBOSS will yield measurements of $d_A(z)$ to an accuracy of 1.2% and measurements of H(z) to 2.1% when combined with the z>0.6 sample of BOSS galaxies. With ~195,000 new emission line galaxy redshifts, we expect BAO measurements of $d_A(z)$ to an accuracy of 3.1% and H(z) to 4.7% at an effective redshift of z= 0.87. A sample of more than 500,000 spectroscopically-confirmed quasars will provide the first BAO distance measurements over the redshift range 0.9<z<2.2, with expected precision of 2.8% and 4.2% on $d_A(z)$ and H(z), respectively. Finally, with 60,000 new quasars and re-observation of 60,000 quasars known from BOSS, we will obtain new Lyman-alpha forest measurements at redshifts z>2.1; these new data will enhance the precision of $d_A(z)$ and H(z) by a factor of 1.44 relative to BOSS. Furthermore, eBOSS will provide new tests of General Relativity on cosmological scales through redshift-space distortion measurements, new tests for non-Gaussianity in the primordial density field, and new constraints on the summed mass of all neutrino species. Here, we provide an overview of the cosmological goals, spectroscopic target sample, demonstration of spectral quality from early data, and projected cosmological constraints from eBOSS.
    Full-text · Article · Aug 2015 · The Astronomical Journal
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    ABSTRACT: Current and future large redshift surveys, as the Sloan Digital Sky Survey IV extended Baryon Oscillation Spectroscopic Survey (SDSS-IV/eBOSS) or the Dark Energy Spectroscopic Instrument (DESI), will use Emission-Line Galaxies (ELG) to probe cosmological models by mapping the large-scale structure of the Universe in the redshift range $0.6 < z < 1.7$. With current data, we explore the halo-galaxy connection by measuring three clustering properties of $g$-selected ELGs as matter tracers in the redshift range $0.6 < z < 1$: (i) the redshift-space two-point correlation function using spectroscopic redshifts from the BOSS ELG sample and VIPERS; (ii) the angular two-point correlation function on the footprint of the CFHT-LS; (iii) the galaxy-galaxy lensing signal around the ELGs using the CFHTLenS. We interpret these observations by mapping them onto the latest high-resolution MultiDark Planck N-body simulation, using a novel (Sub)Halo-Abundance Matching technique that accounts for the ELG incompleteness. ELGs at $z\sim0.8$ live in halos of $(1\pm 0.5)\times10^{12}\,h^{-1}$M$_{\odot}$ and 22.5$\pm2.5$% of them are satellites belonging to a larger halo. The halo occupation distribution of ELGs indicates that we are sampling the galaxies in which stars form in the most efficient way, according to their stellar-to-halo mass ratio.
    Full-text · Article · Jul 2015
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    Zachary Slepian · Daniel J. Eisenstein
    [Show abstract] [Hide abstract]
    ABSTRACT: Though Fourier Transforms (FTs) are a common technique for finding correlation functions, they are not typically used in computations of the anisotropy of the two-point correlation function (2PCF) about the line of sight in wide-angle surveys because the line-of-sight direction is not constant on the Cartesian grid. Here we show how FTs can be used to compute the multipole moments of the anisotropic 2PCF. We also show how FTs can be used to accelerate the 3PCF algorithm of Slepian & Eisenstein (2015). In both cases, these FT methods allow one to avoid the computational cost of pair counting, which scales as the square of the number density of objects in the survey. With the upcoming large datasets of DESI, Euclid, and LSST, FT techniques will therefore offer an important complement to simple pair or triplet counts.
    Preview · Article · Jun 2015
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    ABSTRACT: We explore the bluer star-forming population of the Sloan Digital Sky Survey (SDSS) III/BOSS CMASS DR11 galaxies at $z>0.55$ to quantify their differences, in terms of redshift-space distortions and large-scale bias, with respect to the luminous red galaxy sample. We perform a qualitative analysis to understand the significance of these differences and whether we can model and reproduce them in mock catalogs. Specifically, we measure galaxy clustering in CMASS on small and intermediate scales ($r\lesssim 50\,h^{-1}$Mpc) by computing the two-point correlation function $-$ both projected and redshift-space $-$ of these galaxies, and a new statistic, $\Sigma(\pi)$, able to provide robust information about redshift-space distortions and large-scale bias. We interpret our clustering measurements by adopting a Halo Occupation Distribution (HOD) scheme that maps them onto high-resolution N-body cosmological simulations to produce suitable mock galaxy catalogs. The traditional HOD prescription can be applied to the red and the blue samples, independently, but this approach is unphysical since it allows the same mock galaxies to be either red or blue. To overcome this failure, we modify the standard formulation and infer the red and the blue mock catalogs directly from the full one, so that they are complementary and non-overlapping. This separation is performed by matching the observed CMASS red and blue galaxy fractions and produces reliable and accurate models.
    Full-text · Article · Jun 2015
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    Zachary Slepian · Daniel J. Eisenstein
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    ABSTRACT: We present an algorithm that computes the multipole coefficients of the galaxy three-point correlation function (3PCF) without explicitly considering triplets of galaxies. Rather, centring on each galaxy in the survey, it expands the radially binned density field in spherical harmonics and combines these to form the multipoles without ever requiring the relative angle between a pair about the central. This approach scales with number and number density in the same way as the two-point correlation function, allowing run-times that are comparable, and 500 times faster than a naive triplet count. It is exact in angle and easily handles edge correction. We demonstrate the algorithm on the LasDamas SDSS-DR7 mock catalogues, computing an edge corrected 3PCF out to 90 Mpc h−1 in under an hour on modest computing resources. We expect this algorithm will render it possible to obtain the large-scale 3PCF for upcoming surveys such as Euclid, Large Synoptic Survey Telescope (LSST), and Dark Energy Spectroscopic Instrument.
    Preview · Article · Jun 2015 · Monthly Notices of the Royal Astronomical Society
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    Keisuke Osumi · Shirley Ho · Daniel J. Eisenstein · Mariana Vargas-Magaña
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    ABSTRACT: We investigate the utility and robustness of a new statistic, $\omega_{\ell}\left(r_{c}\right)$, for analyzing Baryon Acoustic Oscillations (BAO). We apply $\omega_{\ell}\left(r_{c}\right)$, introduced in Xu et al. (2010), to mocks and data from the Sloan Digital Sky Survey (SDSS)-III Baryon Oscillation Spectroscopic Survey (BOSS) included in the SDSS Data Release Eleven (DR11). We fit the anisotropic clustering using the monopole and quadrupole of the $\omega_{\ell}\left(r_{c}\right)$ statistic in a manner similar to conventional multipole fitting methods using the correlation function as detailed in (Xu et al. 2012). To test the performance of the $\omega_{\ell}\left(r_{c}\right)$ statistic we compare our results to those obtained using the multipoles. The results are in agreement. We also conduct a brief investigation into some of the possible advantages of using the $\omega_{\ell}\left(r_{c}\right)$ statistic for BAO analysis. The $\omega_{\ell}\left(r_{c}\right)$ analysis matches the stability of the multipoles analysis in response to artificially introduced distortions in the data, without using extra nuisance parameters to improve the fit. When applied to data with systematics, the $\omega_{\ell}\left(r_{c}\right)$ statistic again matches the performance of fitting the multipoles without using nuisance parameters. In all the analyzed circumstances, we find that fitting the $\omega_{\ell}\left(r_{c}\right)$ statistic removes the requirement for extra nuisance parameters.
    Preview · Article · May 2015
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    ABSTRACT: We measure the clustering of X-ray, radio, and mid-IR-selected active galactic nuclei (AGN) at 0.2 < z < 1.2 using multi-wavelength imaging and spectroscopic redshifts from the PRIMUS and DEEP2 redshift surveys, covering 7 separate fields spanning ~10 square degrees. Using the cross-correlation of AGN with dense galaxy samples, we measure the clustering scale length and slope, as well as the bias, of AGN selected at different wavelengths. Similar to previous studies, we find that X-ray and radio AGN are more clustered than mid-IR-selected AGN. We further compare the clustering of each AGN sample with matched galaxy samples designed to have the same stellar mass, star formation rate, and redshift distributions as the AGN host galaxies and find no significant differences between their clustering properties. The observed differences in the clustering of AGN selected at different wavelengths can therefore be explained by the clustering differences of their host populations, which have different distributions in both stellar mass and star formation rate. Selection biases inherent in AGN selection, therefore, determine the clustering of observed AGN samples. We further find no significant difference between the clustering of obscured and unobscured AGN, using IRAC or WISE colors or X-ray hardness ratio.
    No preview · Article · Apr 2015
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    ABSTRACT: We present a tentative detection of the large-scale structure of Lyα emission in the Universe at redshifts $z$ = 2–3.5 by measuring the cross-correlation of Lyα surface brightness with quasars in SDSS/BOSS. We use a million spectra targeting Luminous Red Galaxies at $z$ < 0.8, after subtracting a best fit model galaxy spectrum from each one, as an estimate of the high-redshift Lyα surface brightness. The quasar-Lyα emission cross-correlation is detected on scales 1 ∼ 15h−1 Mpc, with shape consistent with a LambdaCDM model with $\Omega _{\rm m} =0.30^{+0.10}_{-0.07}$. The predicted amplitude of this cross-correlation is proportional to the product of the mean Lyα surface brightness, 〈μα〉, the amplitude of mass fluctuations, and the quasar and Lyα emission bias factors. We infer 〈μα〉 (bα/3) = (3.9 ± 0.9) × 10−21 erg s−1 cm−2 Å−1 arcsec−2, where bα is the Lyα emission bias. If star-forming galaxies dominate this emission, we find ρSFR = (0.28 ± 0.07)(3/bα) yr−1 Mpc−3. For bα = 3, this value is ∼30 times larger than previous estimates from individually detected Lyα emitters, but consistent with the total ρSFR derived from dust-corrected, continuum UV galaxy surveys, if most of the Lyα photons from these galaxies avoid dust absorption and are reemitted after diffusing in large gas haloes. Heating of intergalactic gas by HeII photoionization from quasar radiation or jets may alternatively explain the detected correlation, and cooling radiation from gas in galactic haloes may also contribute. We also detect redshift space anisotropy of the quasar-Lyα emission cross-correlation, finding evidence at the 3.0σ level that it is radially elongated, which may be explained by radiative-transfer effects (Zheng et al. (2011)). Our measurements represent the first application of the intensity mapping technique to optical observations.
    Full-text · Article · Apr 2015 · Monthly Notices of the Royal Astronomical Society

Publication Stats

38k Citations
1,513.32 Total Impact Points

Institutions

  • 2015
    • Texas Christian University
      • Department of Physics and Astronomy
      Fort Worth, Texas, United States
  • 2008-2015
    • Harvard-Smithsonian Center for Astrophysics
      • Smithsonian Astrophysical Observatory
      Cambridge, Massachusetts, United States
    • University of Portsmouth
      • Institute of Cosmology and Gravitation ICG
      Portsmouth, England, United Kingdom
    • New Mexico State University
      • Department of Astronomy
      Las Cruces, New Mexico, United States
  • 1994-2015
    • Harvard University
      • • Department of Astronomy
      • • Department of Physics
      Cambridge, Massachusetts, United States
  • 2011-2014
    • Cambridge College
      Cambridge, Massachusetts, United States
    • The Ohio State University
      • Center for Cosmology and Astoparticle Physics
      Columbus, Ohio, United States
  • 2013
    • Siena College
      • Department Physics and Astronomy
      Troy, New York, United States
  • 2003-2013
    • The University of Arizona
      • Department of Astronomy
      Tucson, Arizona, United States
    • The University of Tokyo
      • Institute for Cosmic Ray Research
      Edo, Tōkyō, Japan
  • 2012
    • University of Utah
      • Department of Physics and Astronomy
      Salt Lake City, Utah, United States
  • 2004-2011
    • Princeton University
      • Department of Astrophysical Sciences
      Princeton, NJ, United States
  • 1999-2011
    • Carnegie Mellon University
      • • Bruce and Astrid McWilliams Center for Cosmology
      • • Department of Physics
      Pittsburgh, Pennsylvania, United States
  • 2009
    • University of California, Berkeley
      • Department of Astronomy
      Berkeley, California, United States
  • 2005-2009
    • Eötvös Loránd University
      • Department of Physics of Complex Systems
      Budapeŝto, Budapest, Hungary
  • 1997-2009
    • Institute for Advanced Study
      Princeton Junction, New Jersey, United States
  • 2007-2008
    • Johns Hopkins University
      • Department of Physics and Astronomy
      Baltimore, Maryland, United States
    • University of Illinois, Urbana-Champaign
      • Department of Astronomy
      Urbana, Illinois, United States
  • 2003-2008
    • University of Pittsburgh
      • Physics and Astronomy
      Pittsburgh, Pennsylvania, United States
  • 2002-2008
    • University of Chicago
      • Department of Astronomy and Astrophysics
      Chicago, IL, United States
  • 2006
    • University of Washington Seattle
      • Department of Astronomy
      Seattle, Washington, United States
    • University of Toronto
      • Canadian Institute for Theoretical Astrophysics
      Toronto, Ontario, Canada