宇宙学与河外天体物理
The turnover scale of the power spectrum is related to the size of the particle horizon at the matter-radiation equality, which can be used as a standard ruler to constrain cosmological parameters. In this work, we apply a model-independent…
We present an assumption-minimized framework for testing late-time cosmological models using Uncalibrated Cosmic Standards (UCS), including standard rulers and standard candles, without relying on absolute calibrations. The method exploits…
Simulation-based inference provides a powerful framework for extracting rich information from nonlinear scales in current and upcoming cosmological surveys, and ensuring its robustness requires stringent validation of forward models. In…
Nowadays, one of the well-known serious challenges in cosmology is the Hubble tension, namely the discrepancy between the Hubble constants from the local observation of Type Ia supernova (SNIa) and the high-$z$ observation of cosmic…
We show, using the pseudo-$C_\ell$ technique, how to estimate cosmic shear and galaxy-galaxy lensing power spectra that are insensitive to the effects of multiple sources of lensing bias including source-lens clustering, magnification bias…
Comparing galaxies across redshifts at fixed cumulative number density is a popular way to estimate the evolution of specific galaxy populations. This method ignores scatter in mass accretion histories and galaxy-galaxy mergers, which can…
The search for the model or ingredients that describe the current vision of our cosmos has led to the creation of a set of highly favorable experiments, and therefore a great flow of information. Due to this torrent of information and the…
We investigate the impact of a DESI motivated dynamic dark energy cosmology on three cosmological anomalies, the $S_8$ tension, the `lensing is low' effect, and observations of strong baryonic feedback. We analyze how these observations…
Current and upcoming cosmological surveys will produce unprecedented amounts of high-dimensional data, which require complex high-fidelity forward simulations to accurately model both physical processes and systematic effects which describe…
The DESI DR2 BAO data, in combination with CMB and different SNIa datasets, exclude the flat $\Lambda$CDM model at more than 2.5$\sigma$ when analyzed through the $w_0w_a$CDM parametrization for evolving dark energy. This simple…
Strongly lensed binary neutron star (NS-NS) mergers are expected to be observed once LIGO/Virgo/Kagra reaches the planned A+ or proposed A\# sensitivity. We demonstrate that the relative transverse velocity of the source-lens system can be…
In this work, we investigate the impact of Poisson noise from stellar-mass primordial black holes (PBHs) on the formation of ultradense dark matter halos (UDMHs). Our findings reveal that the discrete spatial distribution of PBHs…
We present the first detection of the baryon acoustic oscillations (BAO) signal obtained using unblinded data collected during the initial two months of operations of the Stage-IV ground-based Dark Energy Spectroscopic Instrument (DESI).…
The present work deals with a dark energy model that has an oscillating scalar field potential along with a cosmological constant (CC). The oscillating part of the potential represents the contribution of a light axion field in the dark…
A number of studies of WMAP and Planck claimed the low multipole (specially quadrupole) power deficiency in CMB power spectrum. Anomaly in the orientations of the low multipoles have also been claimed. There is a possibility that the power…
We present a catalog of gravitational wave background (GWB) signal templates from cosmic-string networks, based on relevant models proposed in the literature. We classify templates as conventional, based on standard cosmology and Nambu-Goto…
The motivation of this paper is to obtain reliable constraints of transition redshift ($z_{ztr}$) and, in combination with the evolution of the Hubble constant ($H_{0}$) that could alleviate the Hubble tension, discuss the possible origin…
Anisotropic cosmological models have been gaining attention due to various observational hints of large-scale anisotropies. One of the most surprising evidences for the latter is the discovery of a dipole-like directional variation in…
In the framework of general relativity, dark energy was proposed to explain the cosmic acceleration. A pivotal inquiry in cosmology is to determine whether dark energy is the cosmological constant, and if not, the challenge lies in…
Pulsar timing arrays recently found evidence for a gravitational wave background (GWB), likely the stochastic overlap of GWs from many supermassive black hole binaries. Anticipating a continuous gravitational wave (CW) detection from a…