Lensing measurements of the mass distribution in SDSS voids

Using a void catalog from the SDSS survey, we present the first measurements of void clustering and the corresponding void bias. Over the range 30 − 200 Mpc/h the void auto-correlation is detected at 5σ significance for voids of radius 15 − 20 Mpc/h. We also measure the void-galaxy cross-correlation at higher signal-to-noise and compare the inferred void bias with the autocorrelation results. Void bias is constant with scale for voids of a given size, but its value falls from 5.6 ± 1.0 to below zero as the void radius increases from 15 to 30 Mpc/h. The comparison of our measurements with carefully matched galaxy mock catalogs, with no free parameters related to the voids, shows that model predictions can be reliably made for void correlations. We study the dependence of void bias on tracer density and void size with a view to future applications. In combination with our previous lensing measurements of void mass profiles, these clustering measurements provide another step towards using voids as cosmological tracers.

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“…1) over 30 − 200 Mpc/h using the SDSS void sample of Clampitt & Jain (2015). The higher signal-to-noise void-galaxy cross-correlations (Fig.…”

Section: Discussionmentioning

confidence: 83%

“…A new approach to void cosmology involves the joint analysis of observables described in this paper and Clampitt & Jain (2015): void-galaxy, void-void, and void-mass correlations from weak lensing, as well as void abundances. These observables are analogous to cluster cosmology.…”

Section: Discussionmentioning

confidence: 99%

Clustering and bias measurements of SDSS voids

Clampitt

Jain

Sánchez

2016

Mon. Not. R. Astron. Soc.

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“…The void radius may stretch beyond the edge of the survey, into areas which may or may not correspond to voids in the galaxy distribution. To remove such voids which extend far beyond the survey edge, we use the method of Clampitt & Jain (2015). A random point catalogue drawn using the survey mask is generated, and for each void, we calculate the density of random points inside R v .…”

Section: Voids Near the Survey Edgementioning

confidence: 99%

Cosmic voids and void lensing in the Dark Energy Survey Science Verification data

Sánchez

Clampitt

Kovács

et al. 2016

Mon. Not. R. Astron. Soc.

111

121

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Cosmic voids are usually identified in spectroscopic galaxy surveys, where 3D information about the large-scale structure of the Universe is available. Although an increasing amount of photometric data is being produced, its potential for void studies is limited since photometric redshifts induce line-of-sight position errors of ≥50 Mpc h −1 which can render many voids undetectable. We present a new void finder designed for photometric surveys, validate it using simulations, and apply it to the high-quality photo-z redMaGiC galaxy sample of the DES Science Verification data. The algorithm works by projecting galaxies into 2D slices and finding voids in the smoothed 2D galaxy density field of the slice. Fixing the line-of-sight size of the slices to be at least twice the photo-z scatter, the number of voids found in simulated spectroscopic and photometric galaxy catalogues is within 20 per cent for all transverse void sizes, and indistinguishable for the largest voids (R v ≥ 70 Mpc h −1 ). The positions, radii, and projected galaxy profiles of photometric voids also accurately match the spectroscopic void sample. Applying the algorithm to the DES-SV data in the redshift range 0.2 < z < 0.8, we identify 87 voids with comoving radii spanning the range 18-120 Mpc h −1 , and carry out a stacked weak lensing measurement. With a significance of 4.4σ , the lensing measurement confirms that the voids are truly underdense in the matter field and hence not a product of

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“…2) what is the extent to which massive neutrinos impact the reconstructed profile? Recently some work have been done to address the first questions (see for example [70][71][72]); here we focus on the second one. Therefore, in this section we present the analysis for voids identified in the galaxy distribution, which is obtained by post-processing N -body simulations.…”

Section: Voids In the Galaxy Distributionmentioning

confidence: 99%

Voids in massive neutrino cosmologies

Massara

Villaescusa-Navarro

Viel

et al. 2015

J. Cosmol. Astropart. Phys.

137

159

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Abstract. Cosmic voids are a promising environment to characterize neutrino-induced effects on the large-scale distribution of matter in the universe. We perform a comprehensive numerical study of the statistical properties of voids, identified both in the matter and galaxy distributions, in massive and massless neutrino cosmologies. The matter density field is obtained by running several independent N -body simulations with cold dark matter and neutrino particles, while the galaxy catalogs are modeled by populating the dark matter halos in simulations via a halo occupation distribution (HOD) model to reproduce the clustering properties observed by the Sloan Digital Sky Survey (SDSS) II Data Release 7. We focus on the impact of massive neutrinos on the following void statistical properties: number density, ellipticities, two-point statistics, density and velocity profiles. Considering the matter density field, we find that voids in massive neutrino cosmologies are less evolved than those in the corresponding massless neutrinos case: there is a larger number of small voids and a smaller number of large ones, their profiles are less evacuated, and they present a lower wall at the edge. Moreover, the degeneracy between σ 8 and Ω ν is broken when looking at void properties. In terms of the galaxy density field, we find that differences among cosmologies are difficult to detect because of the small number of galaxy voids in the simulations. Differences are instead present when looking at the matter density and velocity profiles around these voids.

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Lensing measurements of the mass distribution in SDSS voids

Cited by 95 publications

References 36 publications

Clustering and bias measurements of SDSS voids

Clustering and bias measurements of SDSS voids

Cosmic voids and void lensing in the Dark Energy Survey Science Verification data

Voids in massive neutrino cosmologies

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