Galaxy clustering and projected density profiles as traced by satellites in photometric surveys: Methodology and luminosity dependence (original) (raw)
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Monthly Notices of the Royal Astronomical Society, 2012
We introduce a new photometric estimator of the Hi mass fraction (M HI /M *) in local galaxies, which is a linear combination of four parameters: stellar mass, stellar surface mass density , N U V −r colour, and g −i colour gradient. It is calibrated using samples of nearby galaxies (0.025 < z < 0.05) with Hi line detections from the GASS and ALFALFA surveys, and it is demonstrated to provide unbiased M HI /M * estimates even for Hi-rich galaxies. We apply this estimator to a sample of ∼24,000 galaxies from the SDSS/DR7 in the same redshift range. We then bin these galaxies by stellar mass and Hi mass fraction and compute projected two point cross-correlation functions with respect to a reference galaxy sample. Results are compared with predictions from current semi-analytic models of galaxy formation. The agreement is good for galaxies with stellar masses larger than 10 10 M ⊙ , but not for lower mass systems. We then extend the analysis by studying the bias in the clustering of Hi-poor or Hi-rich galaxies with respect to galaxies with normal Hi content on scales between 100 kpc and ∼ 5 Mpc. For the Hi-deficient population, the strongest bias effects arise when the Hi-deficiency is defined in comparison to galaxies of the same stellar mass and size. This is not reproduced by the semi-analytic models, where the quenching of star formation in satellites occurs by "starvation" and does not depend on their internal structure. Hi-rich galaxies with masses greater than 10 10 M ⊙ are found to be anti-biased compared to galaxies with "normal" Hi content. Interestingly, no such effect is found for lower mass galaxies.
2014
We present measurements of the luminosity and color-dependence of galaxy clustering at 0.2 < z < 1.0 in the PRIsm MUlti-object Survey (PRIMUS). We quantify the clustering with the redshiftspace and projected two-point correlation functions, ξ(r p , π) and w p (r p), using volume-limited samples constructed from a parent sample of over ∼ 130, 000 galaxies with robust redshifts in seven independent fields covering 9 deg 2 of sky. We quantify how the scale-dependent clustering amplitude increases with increasing luminosity and redder color, with relatively small errors over large volumes. We find that red galaxies have stronger small-scale (0.1 < r p < 1 Mpc/h) clustering and steeper correlation functions compared to blue galaxies, as well as a strong color dependent clustering within the red sequence alone. We interpret our measured clustering trends in terms of galaxy bias and obtain values of b gal ≈ 0.9-2.5, quantifying how galaxies are biased tracers of dark matter depending on their luminosity and color. We also interpret the color dependence with mock catalogs, and find that the clustering of blue galaxies is nearly constant with color, while redder galaxies have stronger clustering in the one-halo term due to a higher satellite galaxy fraction. In addition, we measure the evolution of the clustering strength and bias, and we do not detect statistically significant departures from passive evolution. We argue that the luminosity-and color-environment (or halo mass) relations of galaxies have not significantly evolved since z ∼ 1. Finally, using jackknife subsampling methods, we find that sampling fluctuations are important and that the COSMOS field is generally an outlier, due to having more overdense structures than other fields; we find that 'cosmic variance' can be a significant source of uncertainty for high-redshift clustering measurements.
The Astrophysical Journal, 2015
We report small-scale clustering measurements from the PRIsm MUlti-object Survey (PRIMUS) spectroscopic redshift survey as a function of color and luminosity. We measure the real-space crosscorrelations between 62,106 primary galaxies with PRIMUS redshifts and a tracer population of ∼ 545,000 photometric galaxies over redshifts from z = 0.2 to z = 1. We separately fit a power-law model in redshift and luminosity to each of three independent color-selected samples of galaxies. We report clustering amplitudes at fiducial values of z = 0.5 and L = 1.5L *. The clustering of the 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 the luminosity dependence of the clustering is strongly dependent on physical scale, with greater luminosity dependence being found between r = 0.0625 h −1 Mpc and r = 0.25 h −1 Mpc , compared to the r = 0.5 h −1 Mpc to r = 2 h −1 Mpc range. Moreover, over a range of two orders of magnitude in luminosity, a single power-law fit to the luminosity dependence is not sufficient to explain the increase in clustering at both the bright and faint ends at the smaller scales. We argue that luminosity-dependent clustering at small scales is a necessary component of galaxy-halo occupation models for blue, star-forming galaxies as well as for red, quenched galaxies.
PRIMUS: GALAXY CLUSTERING AS A FUNCTION OF LUMINOSITY AND COLOR AT 0.2 < z < 1
The Astrophysical Journal, 2014
We present measurements of the luminosity and color-dependence of galaxy clustering at 0.2 < z < 1.0 in the PRIsm MUlti-object Survey (PRIMUS). We quantify the clustering with the redshiftspace and projected two-point correlation functions, ξ(r p , π) and w p (r p ), using volume-limited samples constructed from a parent sample of over ∼ 130, 000 galaxies with robust redshifts in seven independent fields covering 9 deg 2 of sky. We quantify how the scale-dependent clustering amplitude increases with increasing luminosity and redder color, with relatively small errors over large volumes. We find that red galaxies have stronger small-scale (0.1 < r p < 1 Mpc/h) clustering and steeper correlation functions compared to blue galaxies, as well as a strong color dependent clustering within the red sequence alone. We interpret our measured clustering trends in terms of galaxy bias and obtain values of b gal ≈ 0.9-2.5, quantifying how galaxies are biased tracers of dark matter depending on their luminosity and color. We also interpret the color dependence with mock catalogs, and find that the clustering of blue galaxies is nearly constant with color, while redder galaxies have stronger clustering in the one-halo term due to a higher satellite galaxy fraction. In addition, we measure the evolution of the clustering strength and bias, and we do not detect statistically significant departures from passive evolution. We argue that the luminosity-and color-environment (or halo mass) relations of galaxies have not significantly evolved since z ∼ 1. Finally, using jackknife subsampling methods, we find that sampling fluctuations are important and that the COSMOS field is generally an outlier, due to having more overdense structures than other fields; we find that 'cosmic variance' can be a significant source of uncertainty for high-redshift clustering measurements.
The Astrophysical …, 2005
Imaging data from the Sloan Digital Sky Survey is used to measure the empirical size-richness relation for a large sample of galaxy clusters. Using population subtraction methods, we determine the radius at which the cluster galaxy number density is 200Ω −1 m times the mean galaxy density, without assuming a model for the radial distribution of galaxies in clusters. If these galaxies are unbiased on Mpc scales, this galaxy-density-based R 200 reflects the characteristic radii of clusters. We measure the scaling of this characteristic radius with richness over an order of magnitude in cluster richness, from rich clusters to poor groups. We use this information to examine the radial profiles of galaxies in clusters as a function of cluster richness, finding that the concentration of the galaxy distribution decreases with richness and is systematically lower than the concentrations measured for dark matter profiles in N-body simulations. Using these scaled radii, we investigate the behavior of the cluster luminosity function, and find that it is well matched by a Schechter function for galaxies brighter than M r = −18 only after the central galaxy has been removed. We find that the luminosity function varies with richness and with distance from the cluster center, underscoring the importance of using an aperture that scales with cluster mass to compare physically equivalent regions of these different systems. We note that the lowest richness systems in our catalog have properties consistent with those expected of the earliest-forming halos; our cluster-finding algorithm, in addition to reliably finding clusters, may be efficient at finding fossil groups.
The DEEP2 Galaxy Redshift Survey: Clustering of Galaxies as a Function of Luminosity at z = 1
The Astrophysical Journal, 2006
We measure the clustering of DEEP2 galaxies at z = 1 as a function of luminosity on scales 0.1 h −1 Mpc to 20 h −1 Mpc. Drawing from a parent catalog of 25,000 galaxies at 0.7 < z < 1.3 in the full DEEP2 survey, we create volume-limited samples having upper luminosity limits between M B = −19 and M B = −20.5, roughly 0.2 − 1L * at z = 1. We find that brighter galaxies are more strongly clustered than fainter galaxies and that the slope of the correlation function does not depend on luminosity for L < L * . The brightest galaxies, with L > L * , have a steeper slope. The clustering scale-length, r 0 , varies from 3.69 ± 0.14 for the faintest sample to 4.43 ± 0.14 for the brightest sample. The relative bias of galaxies as a function of L/L * is steeper than the relation found locally for SDSS galaxies ) over the luminosity range that we sample. The absolute bias of galaxies at z ∼ 1 is scale-dependent on scales r p < 1 h −1 Mpc, and rises most significantly on small scales for the brightest samples. For a concordance cosmology, the large-scale bias varies from 1.26 ± 0.04 to 1.54 ± 0.05 as a function of luminosity and implies that DEEP2 galaxies reside in dark matter halos with a minimum mass of ∼ 1 − 3 × 10 12 h −1 M ⊙ .
The Astrophysical Journal, 2012
The Sloan Digital Sky Survey (SDSS) surveyed 14,555 square degrees, and delivered over a trillion pixels of imaging data. We present a study of galaxy clustering using 900,000 luminous galaxies with photometric redshifts, spanning between z = 0.45 and z = 0.65, constructed from the SDSS using methods described in Ross et al. (2011). This data-set spans 11,000 square degrees and probes a volume of 3h −3 Gpc 3 , making it the largest volume ever used for galaxy clustering measurements. We describe in detail the construction of the survey window function and various systematics affecting our measurement. With such a large volume, high precision cosmological constraints can be obtained given a careful control and understanding of the observational systematics. We present a novel treatment of the observational systematics and its applications to the clustering signals from the data set. In this paper, we measure the angular clustering using an optimal quadratic estimator at 4 redshift slices with an accuracy of ∼ 15% with bin size of δ l = 10 on scales of the Baryon Acoustic Oscillations (BAO) (at ∼ 40 − 400). We also apply corrections to the power-spectra due to systematics, and derive cosmological constraints using the full-shape of the power-spectra. For a flat ΛCDM model, when combined with Cosmic Microwave Background Wilkinson Microwave Anisotropy Probe 7 (WMAP7) and H 0 constraints from using 600 Cepheids observed by Wide Feild Camera 3 (WFC3) (HST) , we find Ω Λ = 0.73 ± 0.019 and H 0 to be 70.5 ± 1.6 s −1 Mpc −1 km. For an open ΛCDM model, when combined with WMAP7 + HST, we find Ω K = 0.0035 ± 0.0054, improved over WMAP7+HST alone by 40%. For a wCDM model, when combined with WMAP7+HST+SN, we find w = −1.071 ± 0.078, and H 0 to be 71.3 ± 1.7 s −1 Mpc −1 km, which is competitive with the latest large scale structure constraints from large spectroscopic surveys such as SDSS Data Release 7 (DR7) (Reid et al. 2010, Percival et al. 2010, Montesano et al. 2011) and WiggleZ (Blake et al. 2011). We also find that systematic-corrected power-spectra gives consistent constraints on cosmological models when compared with pre-systematic correction power-spectra in the angular scales of interest. The SDSS-III Data Release 8 (SDSS-III DR8) Angular Clustering Data allows a wide range of investigations into the cosmological model, cosmic expansion (via BAO), Gaussianity of initial conditions and neutrino masses. Here, we refer to our companion papers (Seo et al. 2011, de Putter et al. 2011) for further investigations using the clustering data. Our calculation of survey selection function, systematics maps, likelihood function for COSMOMC package will be released at
Galaxy clustering in the completed SDSS redshift survey: the dependence on color and luminosity
We measure the luminosity and color dependence of galaxy clustering in the largest-ever galaxy redshift survey, the main galaxy sample of the Sloan Digital Sky Survey (SDSS) Seventh Data Release (DR7). We focus on the projected correlation function w p (r p ) of volume-limited samples, extracted from the parent sample of ∼ 700, 000 galaxies over 8000 deg 2 , extending up to redshift of 0.25. We interpret our measurements using halo occupation distribution (HOD) modeling assuming a ΛCDM cosmology (inflationary cold dark matter with a cosmological constant). The amplitude of w p (r p ) grows slowly with luminosity for L < L * and increases sharply at higher luminosities, with a large-scale bias factor b(> L) × (σ 8 /0.8) = 1.06 + 0.21(L/L * ) 1.12 , where L is the sample luminosity threshold. At fixed luminosity, redder galaxies exhibit a higher amplitude and steeper correlation function, a steady trend that runs through the "blue cloud" and "green valley" and continues across the "red sequence." The cross-correlation of red and blue galaxies is close to the geometric mean of their autocorrelations, dropping slightly below at r p < 1 h −1 Mpc. The luminosity trends for the red and blue galaxy populations separately are strikingly different. Blue galaxies show a slow but steady increase of clustering strength with luminosity, with nearly constant shape of w p (r p ). The large-scale clustering of red galaxies shows little luminosity dependence until a sharp increase at L > 4L * , but the lowest luminosity red galaxies (0.04 − 0.25L * ) show very strong clustering on small scales (r p < 2 h −1 Mpc). Most of the observed trends can be naturally understood within the ΛCDM+HOD framework. The growth of w p (r p ) for higher luminosity galaxies reflects an overall shift in the mass scale of their host dark matter halos, in particular an increase in the minimum host halo mass M min . The mass at which a halo has, on average, one satellite galaxy brighter than L is M 1 ≈ 17M min (L) over most of the luminosity range, with a smaller ratio above L * . The growth and steepening of w p (r p ) for redder galaxies reflects the increasing fraction of galaxies that are satellite systems in high mass halos instead of central systems in low mass halos, a trend that is especially marked at low luminosities. Our extensive measurements, provided in tabular form, will allow detailed tests of theoretical models of galaxy formation, a firm grounding of semi-empirical models of the galaxy population, and new constraints on cosmological parameters from combining real-space galaxy clustering with mass-sensitive statistics such as redshift-space distortions, cluster mass-to-light ratios, and galaxy-galaxy lensing.
The Contribution of Normal, Dim, and Dwarf Galaxies to the Local Luminosity Density
The Astrophysical Journal, 1999
From the Hubble Deep Field catalog presented in we derive the local (0.3 < z < 0.5) bivariate brightness distribution (BBD) of field galaxies within a 326 Mpc 3 volume-limited sample. The sample contains 47 galaxies which uniformally sample the underlying galaxy population within the specified redshift, magnitude and surface brightness limits (0.3 < z < 0.5, −21.3 < M B < −13.7 mags, 18.0 < µ B < 24.55 mags/2 ′′ ). We conclude: (i) A luminosity-surface brightness relation exists for both the field and cluster galaxy populations, M B ≈ [(1.5 ± 0.2)µ e − (50 ± 2)], (ii) Luminous low surface brightness galaxies account for < 10% of the L * population, (iii) Low luminosity low surface brightness galaxies outnumber Hubble types by a factor of ∼ 1.4, however their space density is not sufficient to explain the faint blue excess either by themselves or as faded remnants. In terms of the local luminosity density and galaxy dynamical mass budget, normal galaxies (i.e. Hubble tuning fork) contribute 88% and 72% respectively. This compares to 7% and 12% for dim galaxies and 5% and 16% for dwarf galaxies (within the above specified limits).