1509.06371
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in the correlation function of LOWZ and CMASS galaxies in Data Release 12
Cuesta et al
BAO signal in CMASS and LOWZ samples from DR12 of BOSS: total volume probed is 14.5 Gpc^3, a 10% increment from DR11. Analysis of the spherically averaged correlation function, infer a distance to z=0.57 of D_V(z)r^fid_d/r_d = 2028±19 Mpc and a distance to z=0.32 of D_V(z)r^fid_d/r_d = 1263±21 Mpc assuming a cosmology in which r^fid_d = 147.10 Mpc. From the anisotropic analysis, find an angular diameter distance to z=0.57 of D_A(z)r^fid_d/r_d = 1401±19 Mpc and a distance to z=0.32 of 981±20 Mpc, a 1.4% and 2.0% measurement respectively. These cosmic distance scale constraints are in excellent agreement with a LCDM model with cosmo params released by Planck 2015.
1509.06373
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: BAO measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies
Gil-Marín, Percival, Cuesta, et al
Present an anisotropic analysis of the BAO scale in the final DR12 BOSS data release. Independently analyse the LOWZ and CMASS galaxy samples: the LOWZ sample contains 361k galaxies with an effective z of z_LOWZ=0.32, and the CMASS sample consists of 777k galaxies with an effective redshift of z_CMASS=0.57. Extract the BAO peak position from the monopole power spectrum amount, alpha_0, and from the mu^2 moment, alpha^2. Report H(z_LOWZ)r_s(z_d)=(11.64±0.62)e3 km/s, and D_A(z_LOWZ)/r_s(z_d)=0.85±0.17 with a cross-correlation coefficient of r_HD_A=0.42, for the LOWZ sample; and H(z_CMASS)r_s(z_d)=)14.56±0.38)e3 km/s and D_A(z_CMASS)/r_s(z_d)=9.42±0.13 with a cross-correlation coefficient of r_HD_A=0.51, for the CMASS sample. Combine these results with the measurements of the BAO peak position in the monopole and quadrupole correlation function of the same dataset [see above] and report the consensus values: H(z_LOWZ)r_s(z_d)=(11.64±0.70)e3 km/s and D_A(z_LOWZ)/r_s(z_d)=6.76±0.15 with r_HD_A=0.35 for the LOWZ sample; and H(z_CMASS)r_s(z_d)=(14.66±0.42)e3 km/s and D_A(z_CMASS)/r_s(z_d)=9.47±0.13 with r_HD_A=0.54 for the CMASS sample.
1509.06376
Detection effects of filaments on galaxy properties in the Sloan Digital Sky Survey III
Chen, Ho, Mandelbaum, Bahcall, et al
Study the effects of filaments on galaxy properties on SDSS DR12 using filaments from the 'Cosmic Web Reconstruction' catalogue (Chen+2015), a publicly available filament catalogue for SDSS. Since filaments are tracers of medium-to-high density regions, expect that galaxy properties associated with the environment are dependent on the distance to the nearest filament. Analysis demonstrates a red galaxy or a high-mass galaxy tend to reside closer to filaments than a blue or low-mass galaxy. After adjusting the effect from stellar mass, on average, late-forming galaxies or large galaxies have a shorter distance to filaments than early-forming galaxies or small galaxies. For the Main galaxy sample, all signals are very significant (>5 sigma). For the LOWZ and CMASS samples, most of the signals are significant (with >3 sigma). The filament effects observed persist until z=0.7 (the edge of the CMASS sample). Comparing the results to those using the galaxy distances from redMaPPer galaxy clusters as a reference, find a similar result between filaments and clusters. Findings illustrate the strong correlation of galaxy properties with proximity to density ridges, strongly supporting the claim that density ridges are good tracers of filaments.
1509.06384
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Effect of smoothing of density field on reconstruction and anisotropic BAO analysis
Vargas-Magaña, Ho, Fromeneteau, Cuesta
The reconstruction algorithm introduced by Eisenstein+2007, which is widely used in clustering analysis, is based on the inference of the displacement using the Zeldovich approximation from the Gaussian-smooth density field in redshift space. The smoothing-scale applied to the density field affects the inferred displacement field that is used to move the particles, and partially erase their nonlinear evolution. In this article, explore this crucial step on the reconstruction algorithm. Study the performance of the reconstruction technique from two different aspects: the first one, the anisotropic clustering going beyond previous studies, which focus on isotropic clustering, the second is its effect on displacement field. Find that smoothing has a strong effect in the quadrupole of the correlation function and affects the accuracy and precision at which we can measure D_A(z) and H(z). find that the best smoothing scale for BOSS-CMASS galaxies is between 5-10Mpc/h. Varying from the "usual" 15Mpc/h to 5Mpc/h show ~0.5% variations in D_A(z) and H(z) and uncertainties are reduced by 40 and 30%, respectively. Also find that the accuracy of velocity field reconstruction depends strongly on the smoothing scale used for the density field. Measure the bias and uncertainties associated with different choices of smoothing length.
1509.06400
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Mock galaxy catalogues for the final BOSS data release
Kitaura et al
Reproduce the galaxy clustering catalog from BOSS DR12 with high fidelity on all relevant scales in order to allow a robust analysis of BAOs and z-space distortions. Generated 12k MultiDark patchy light-cones corresponding to an effective volume of ~192k [Gpc/h]^3 (the largest ever simulated volume), including cosmic evolution in the range form 0.15 to 0.75. The mocks have been calibrated using a reference galaxy catalogue based on the Halo Abundance Matching modeling of the BOSS DR12 galaxy clustering at a and on the data themselves. The production of the MultiDark PATCHY BOSS DR12 mocks follows 3 steps. (1) apply the PATCHY-code to generate a DM field and an object distribution including nonlinear stochastic galaxy bias. (2) run the halo/stellar distribution reconstruction HADRON-code to assign masses to the various objects. This step uses the mass distribution as a function of local density and nonlocal indicators (i.e., tidal-field tensor eigenvalues and relative halo-exclusion separation for massive objects) from the reference simulation applied to the corresponding PATCHY dark matter and galaxy distribution. (3) in consistency with the observed catalogues, apply the SUGAR-code to build the light-cones. This reproduces the number density, clustering bias, selection function, and survey geometry of the different BOSS galaxy samples. The resulting MultiDark PATCHY mock light-cones reproduce, in general within 1-sigma, the power spectrum and two-point correlation functions up to k=0.3 h/Mpc and down to a few Mpc scales, respectively, and the 3PT statistics of the BOSS DR12 galaxy samples, for arbitrary stellar mass bins.
1509.06404
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: modeling the clustering and halo occupation distribution of BOSS-CMASS galaxies in the Final Data Release
Rodríguez-Torres, et al
Present a study of the clustering and HOD of BOSS CMASS galaxies in 0.43<z<0.7 drawn from the final SDSS-III data release. Compare the BOSS results with the predictions of a halo abundance matching (HAM) clustering model that assigns galaxies to dark matter haloes selected from the large BigMultiDark N-body sims of a flat LCDM Planck cosmology. Compare the observational data with the simulated ones on a light-cone constructed from 20 subsequent outputs of the simulation. Observational effects such as incompleteness, geometry, veto masks and fiber collisions are included in the model, which reproduces within 1-sigma errors the observed monopole of the 2PCF at all relevant scales from the smallest scales 0.5 Mpc/h, up to scale beyond the BAO feature. This model also agrees remarkable well with the BOSS galaxy power spectrum (up to k~1 h/Mpc), and the 3PCF. The quadrupole of the correlation function presents some tensions with observations. Discuss possible causes that can explain this disagreement, including target selection effects. Overall, the standard HAM model describes remarkably well the clustering statistics of the CMASS sample. Compare the stellar to halo mass relation for the CMASS sample measured using weak lensing in the CFHT Stripe 82 survey with the prediction of the clustering model, and find a good agreement within 1-sigma. The BigMD-BOSS light-cone catalogue including properties of BOSS galaxies such as stellar masses, M/L ratios, luminosities, velocity dispersion and halo properties is made publicly available.
1509.06417
The scale-dependence of halo assembly bias
Sunayama, Hearin, Padmanabhan, Leauthaud
The 2PT clustering of MD haloes is influenced by halo properties besides mass, a phenomenon referred to as halo assembly bias. Using the depth of the gravitational potential well, V_max, as the secondary halo property, present the first study of the scale-dependence assembly bias. In the large-scale linear regime, r>10Mpc/h, the findings are in keeping with previous results: at the low-mass end (M_vir<M_coll~1e12.5 Msun), haloes with high-V_max show stronger large-scale clustering relative to halos with low-V_max of the same mass, this trend weakens and reverses for M_vir>M_coll. In the nonlinear regime, assembly bias in low-mass haloes exhibits a pronounced scale-dependent "bump" at 500 kpc/h - 5Mpc/h, a new result. This feature weakens and eventually vanishes for haloes of higher mass. Show that this scale-dependent signature can primarily be attributed to a special subpopulation of ejected halos, defined as present-day host haloes that were previously members of higher-mass halo at some point in their past history. A corollary of the results is that galaxy clustering on scales of r~1-2Mpc/h can be impacted by up to ~15% by the choice of the halo property used in the halo model, even for stellar mass-limited samples.
No comments:
Post a Comment