Abstract
We search the Planck data for a thermal Sunyaev–Zel’dovich (tSZ) signal due to gas filaments between pairs of Luminous Red Galaxies (LRGs) taken from the Sloan Digital Sky Survey Data ...Release 12 (SDSS/DR12). We identify ∼260 000 LRG pairs in the DR12 catalogue that lie within 6–10 $h^{-1} \, \mathrm{Mpc}$ of each other in tangential direction and within 6 $h^{-1} \, \mathrm{Mpc}$ in radial direction. We stack pairs by rotating and scaling the angular positions of each LRG so they lie on a common reference frame, then we subtract a circularly symmetric halo from each member of the pair to search for a residual signal between the pair members. We find a statistically significant (5.3σ) signal between LRG pairs in the stacked data with a magnitude Δy = (1.31 ± 0.25) × 10−8. The uncertainty is estimated from two Monte Carlo null tests which also establish the reliability of our analysis. Assuming a simple, isothermal, cylindrical filament model of electron overdensity with a radial density profile proportional to rc/r (as determined from simulations), where r is the perpendicular distance from the cylinder axis and rc is the core radius of the density profile, we constrain the product of overdensity and filament temperature to be $\delta _\mathrm{ c} \times (T_{\rm e}/10^7 \, {\rm K}) \times (r_\mathrm{ c}/0.5h^{-1} \, {\rm Mpc}) = 2.7 \pm 0.5$. To our knowledge, this is the first detection of filamentary gas at overdensities typical of cosmological large-scale structure. We compare our result to the BAHAMAS suite of cosmological hydrodynamic simulations (McCarthy et al. 2017) and find a slightly lower, but marginally consistent Comptonization excess, Δy = (0.84 ± 0.24) × 10−8.
A network of synchronized detectors can increase the likelihood of discovering the QCD axion within the axion quark nugget (AQN) dark matter model. A similar network can also discriminate the x rays ...emitted by the AQNs from the background signal. These networks can provide information on the directionality of the dark matter flux (if any), as well as its velocity distribution, and can therefore test the Standard Halo Model. We show that the optimal configuration to detect AQN-induced axions is a triangular network of stations 100 km apart. For x rays, the optimal network is an array of tetrahedral units.
We present a study of the relation between dark matter halo mass and the baryonic content of their host galaxies, quantified through galaxy luminosity and stellar mass. Our investigation uses 154 ...deg2 of Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS) lensing and photometric data, obtained from the CFHT Legacy Survey. To interpret the weak lensing signal around our galaxies, we employ a galaxy-galaxy lensing halo model which allows us to constrain the halo mass and the satellite fraction. Our analysis is limited to lenses at redshifts between 0.2 and 0.4, split into a red and a blue sample. We express the relationship between dark matter halo mass and baryonic observable as a power law with pivot points of
and
for luminosity and stellar mass, respectively. For the luminosity-halo mass relation, we find a slope of 1.32 ± 0.06 and a normalization of
for red galaxies, while for blue galaxies the best-fitting slope is
and the normalization is
. Similarly, we find a best-fitting slope of
and a normalization of
for the stellar mass-halo mass relation of red galaxies, while for blue galaxies the corresponding values are
and
. All numbers convey the 68 per cent confidence limit. For red lenses, the fraction which are satellites inside a larger halo tends to decrease with luminosity and stellar mass, with the sample being nearly all satellites for a stellar mass of
. The satellite fractions are generally close to zero for blue lenses, irrespective of luminosity or stellar mass. This, together with the shallower relation between halo mass and baryonic tracer, is a direct confirmation from galaxy-galaxy lensing that blue galaxies reside in less clustered environments than red galaxies. We also find that the halo model, while matching the lensing signal around red lenses well, is prone to overpredicting the large-scale signal for faint and less massive blue lenses. This could be a further indication that these galaxies tend to be more isolated than assumed.
We search for potential galactic and extragalactic dust contamination in thermal Sunyaev-Zeldovich maps derived from the Planck data. To test for contamination, we apply a variety of galactic dust ...and cosmic infrared background (CIB) models to the data as part of the y map reconstruction process. We evaluate the level of contamination by cross-correlating these y maps with mass tracers based on weak lensing data. The lensing data we use are the convergence map, κ, from the Red Sequence Cluster Lensing survey, and the cosmic microwave background (CMB) lensing potential map, φ, from the Planck Collaboration. We make a CIB-subtracted y map and measure the cross-correlation between it and the lensing data. By comparing it with CIB-contaminated cross-correlation, we find that the cross-correlation between κ and y is only slightly contaminated by CIB signal, at the level of 6.8 3.5%, which implies that previous detections of κ × y are robust to CIB contamination. However, we find that φ × y is more significantly contaminated, by 16.7 3.5%, because the CMB lensing potential probes higher redshift sources that overlap more with the CIB sources. We find that Galactic dust does not significantly contaminate either cross-correlation signal.
The unknown nature of ‘dark energy’ motivates continued cosmological tests of large-scale gravitational physics. We present a new consistency check based on the relative amplitude of non-relativistic ...galaxy peculiar motions, measured via redshift-space distortion, and the relativistic deflection of light by those same galaxies traced by galaxy–galaxy lensing. We take advantage of the latest generation of deep, overlapping imaging and spectroscopic data sets, combining the Red Cluster Sequence Lensing Survey, the Canada–France–Hawaii Telescope Lensing Survey, the WiggleZ Dark Energy Survey and the Baryon Oscillation Spectroscopic Survey. We quantify the results using the ‘gravitational slip’ statistic E
G, which we estimate as 0.48 ± 0.10 at z = 0.32 and 0.30 ± 0.07 at z = 0.57, the latter constituting the highest redshift at which this quantity has been determined. These measurements are consistent with the predictions of General Relativity, for a perturbed Friedmann–Robertson–Walker metric in a Universe dominated by a cosmological constant, which are E
G = 0.41 and 0.36 at these respective redshifts. The combination of redshift-space distortion and gravitational lensing data from current and future galaxy surveys will offer increasingly stringent tests of fundamental cosmology.
We present a new measurement of the mass-concentration relation and the stellar-to-halo mass ratio over the halo-mass range 5 × 1012 to 2 × 1014 M . To achieve this, we use weak lensing measurements ...from the Canada-France-Hawaii Telescope Stripe 82 Survey (CS82), combined with the central galaxies from the redMaPPer cluster catalog and the LOWZ/CMASS galaxy sample of the Sloan Digital Sky Survey-III Baryon Oscillation Spectroscopic Survey Tenth Data Release. The stacked lensing signals around these samples are modeled as a sum of contributions from the central galaxy, its dark matter halo, and the neighboring halos, as well as a term for possible centering errors. We measure the mass-concentration relation: with A = 5.24 1.24, B = −0.13 0.10 for 0.2 < z < 0.4, and A = 6.61 0.75, B = −0.15 0.05 for 0.4 < z < 0.6. These amplitudes and slopes are completely consistent with predictions from recent simulations. We also measure the stellar-to-halo mass ratio for our samples, and find results consistent with previous measurements from lensing and other techniques.
ABSTRACT
We construct the mean thermal Sunyaev–Zel’dovich (tSZ) Comptonization y-profile around luminous red galaxies (LRGs) in the redshift range 0.16 < z < 0.47 from the Sloan Digital Sky Survey ...Data Release 7 using the Planck y-map. We detect a significant tSZ signal out to ∼30 arcmin, which is well beyond the 10 arcmin angular resolution of the y-map and well beyond the virial radii of the LRGs. We compare the measured profile with predictions from the cosmo-OWLS suite of cosmological hydrodynamical simulations. The best agreement is obtained for models that include efficient feedback from active galactic nuclei, over and above feedback associated with star formation. We also compare our results with predictions based on the halo model with a universal pressure profile giving the y-signal. The predicted profile is consistent with the data when using stacked weak lensing measurements to estimate the halo masses of the LRGs, but only if we account for the clustering of neighbouring haloes via a two-halo term.
ABSTRACT
We confront the universal pressure profile (UPP) proposed. with the recent measurement of the cross-correlation function of the thermal Sunyaev–Zeldovich (tSZ) effect from Planck and weak ...gravitational lensing measurement from the Red Cluster Sequence Lensing Survey. By using the halo model, we calculate the prediction of ξy−κ (lensing convergence and Compton-y parameter) and $\xi ^{y-\gamma _{\rm t}}$ (lensing shear and Compton-y parameter) and fit the UPP parameters by using the observational data. We find consistent UPP parameters when fixing the cosmology to either WMAP 9-yr or Planck 2018 best-fitting values. The best constrained parameter is the pressure profile concentration c500 = r500/rs, for which we find $c_{500} = 2.68^{+1.46}_{-0.96}$ (WMAP-9) and $c_{500} = 1.91^{+1.07}_{-0.65}$ (Planck-2018) for the $\xi ^{y-\gamma _t}$ estimator. The shape index for the intermediate radius region α parameter is constrained to $\alpha =1.75^{+1.29}_{-0.77}$ and $\alpha = 1.65^{+0.74}_{-0.5}$ for WMAP-9 and Planck-2018 cosmologies, respectively. Propagating the uncertainties of the UPP parameters to pressure profiles results in a factor of 3 uncertainty in the shape and magnitude. Further investigation shows that most of the signal of the cross-correlation comes from the low-redshift, inner halo profile (r ≤ rvir/2) with halo mass in the range of 1014–$10^{15}{\, {\rm M}_{\odot }}$, suggesting that this is the major regime that constitutes the cross-correlation signal between weak lensing and tSZ.
ABSTRACT
The discrepancy between the weak lensing (WL) and the Planck measurements of S8 has been a subject of several studies. Assuming that residual systematics are not the cause, these studies ...tend to show that a strong suppression of the amplitude of the mass power spectrum P(k) in the late Universe at high k could resolve it. The WL signal at the small scale is sensitive to various effects not related to lensing, such as baryonic effects and intrinsic alignment. These effects are still poorly understood therefore the accuracy of P(k) depends on the modelling precision of these effects. A common approach for calculating P(k) relies on a halo model. Among the various components necessary for the construction of P(k) in the halo model framework, the halo mass function (HMF) is an important one. Traditionally, the HMF has been assumed to follow a fixed model, motivated by dark matter-only numerical simulations. Recent literature shows that baryonic physics, among several other factors, could affect the HMF. In this study, we investigate the impact of allowing the HMF to vary. This provides a way of testing the validity of the halo model-HMF calibration using data. In the context of the aforementioned S8 discrepancy, we find that the Planck cosmology is not compatible with the vanilla HMF for both the DES-y3 and the KiDS-1000 data. Moreover, when the cosmology and the HMF parameters are allowed to vary, the Planck cosmology is no longer in tension. The modified HMF predicts a matter power spectrum with a $\sim 25~{{\ \rm per\ cent}}$ power loss at k ∼ 1 h Mpc−1, in agreement with the recent studies that try to mitigate the S8 tension with modifications in P(k). We show that stage IV surveys will be able to measure the HMF parameters with a few per cent accuracy.
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