Particle Motion and Plasma Effects on Gravitational Weak Lensing in Lorentzian Wormhole Spacetime

Here we study particle motion in the specific Lorentzian wormhole spacetime characterized, in addition to the total mass M, with the dimensionless parameter λ. In particular we calculate the radius of the innermost stable circular orbit (ISCO) for test particles and the photonsphere for massless particles. We show that the effect of the dimensionless wormhole parameter decreases the ISCO radius and the radius of the photon orbit. Then, we study plasma effects on gravitational weak lensing in wormhole spacetime and obtain the deflection angle of the light. We show that the effect of λ decreases the deflection angle. We study the effects of uniform and non-uniform plasma on the light deflection angle separately, and show that the uniform plasma causes the deflection angle to be smaller in contrast to the non-uniform plasma.

Cosmological consequences of intrinsic alignments supersample covariance

ABSTRACT We examine cosmological constraints from high-precision weak-lensing surveys including supersample covariance (SSC) due to the finite survey volume. Specifically, we focus on the contribution of beat coupling in the intrinsic alignments as a part of full cosmic shear signal under flat-sky approximation. The SSC-effect grows by going to lower redshift bin and indicates considerable footprint on the intermediate and high multipoles for cumulative signal-to-noise ratio (SNR). The SNR is reduced by $\approx 10{{\ \rm per\ cent}}$ as a consequence of including the intrinsic alignment SSC, for the full cosmic shear signal, depending on the amplitude of intrinsic alignments, the ellipticity dispersion, and the survey redshift ranges, while the contribution of photometric redshift error can be ignored in the cumulative SNR. Using the Fisher-matrix formalism, we find that the impact of large modes beyond the volume of the surveys on the small modes alters the intrinsic alignments. However, corresponding impact on the cosmological parameters’ estimation is marginal compared to that of for gravitational weak lensing, particularly, when all available redshift bins are considered. Our results also demonstrate that including SSC-effect on the intrinsic alignments in the analytical covariance matrix of full cosmic shear leads to increase marginally the confidence interval for σ8 by $\approx 10{{\ \rm per\ cent}}$ for a sample with almost high intrinsic alignment amplitude.

Probing cosmology and cluster astrophysics with multiwavelength surveys – I. Correlation statistics

ABSTRACT Upcoming multiwavelength astronomical surveys will soon discover all massive galaxy clusters and provide unprecedented constraints on cosmology and cluster astrophysics. In this paper, we investigate the constraining power of the multiband cluster surveys, through a joint analysis of three observables associated with clusters of galaxies, including thermal Sunyaev–Zel’dovich (tSZ) effect in cosmic microwave background (CMB), X-ray emission of ionized gas, and gravitational weak lensing effect of background galaxies by the cluster’s gravitational potential. We develop a theoretical framework to predict and interpret two-point correlation statistics among the three observables using a semi-analytic model of intracluster medium (ICM) and halo-based approach. In this work, we show that the auto- and cross-angular power spectra in tSZ, X-ray, and lensing statistics from upcoming missions (eROSITA, CMB-S4, and LSST) can help break the degeneracy between cosmology and ICM physics. These correlation statistics are less sensitive to selection biases, and are able to probe ICM physics in distant, faint, and small clusters that are otherwise difficult to be detected individually. We show that the correlation statistics are able to provide cosmological constraints comparable to the conventional cluster abundance measurements, while constraining cluster astrophysics at the same time. Our results indicate that the correlation statistics can significantly enhance the scientific returns of upcoming multiwavelength cluster surveys.