宇宙学与河外天体物理

In this work, we propose a model of warm inflation driven by axion-like particles interacting with $U(1)$ gauge fields, with implications for the early universe's thermal evolution. By extending traditional warm inflation models, we…

Recent baryon acoustic oscillation (BAO) measurements from the Dark Energy Spectroscopic Instrument (DESI) collaboration have renewed interest in dynamical dark energy models, particularly those that cross the "phantom divide" ($w_{\rm DE}…

Observations over the past decade have shown that galaxy clusters undergo the most transformative changes during the $z = 1.5 - 2$ epoch. However, challenges such as low lensing efficiency, high shape measurement uncertainty, and a scarcity…

The cosmography known as the Pad\'{e} polynomials has been widely used in the reconstruction of luminosity distance, and the orders of Pad\'{e} polynomials influence the reconstructed result derived from Pad\'{e} approximation. In this…

The James Webb Space Telescope (JWST) observations have identified a class of compact galaxies at high redshifts ($4 \lesssim z \lesssim 11$), dubbed "little red dots" (LRDs). The supermassive black holes (SMBHs) of…

Extragalactic foregrounds -- most notably the Cosmic Infrared Background (CIB) and the thermal Sunyaev-Zel'dovich (tSZ) effect -- exhibit complex, non-Gaussian structure and correlations that can bias analyses of small-scale cosmic…

Redshift-independent distances underpin much of astrophysics, and there exists a plethora of methods to estimate them. However, the extent to which the distances they imply are consistent, while crucial for the integrity of the distance…

Gravitational lensing is a universal phenomenon: it affects both gravitational waves (GWs) and electromagnetic signals travelling through the gravitational field of a massive object. In this work, we explore the prospects of observing…

Wide-angle and relativistic corrections to the Newtonian and flat-sky approximations are important for accurate modeling of the galaxy power spectrum of next-generation galaxy surveys. In addition to Doppler and Sachs-Wolfe relativistic…

With the advent of next-generation surveys, constraints on cosmological parameters are anticipated to become more stringent, particularly for the total neutrino mass. This study forecasts such constraints utilizing galaxy clusters from the…

Grid type pre-initial conditions are commonly used to initialize particle positions in cosmological simulations. While these conditions are known to produce noticeable numerical artifacts in void regions, their impact on halo properties has…

We consider models where the dilaton, seen as the pseudo-Goldstone boson of broken scale invariance, plays the role of dark energy. We revisit Weinberg's theorem and show that quantum corrections induced by the graviton lead to the…

The rotation of the linear polarisation plane of photons during propagation, also known as cosmic birefringence, is a powerful probe of parity-violating extensions of standard electromagnetism. Using Planck legacy data, we confirm previous…

This paper investigates the utility of Fast Radio Bursts (FRBs) as novel observational probes to constrain models of interacting dark energy (IDE). By leveraging FRB dispersion measures (DMs) and redshifts, we perform a comprehensive…

We extend our super-resolution and emulation framework for cosmological dark matter simulations to include hydrodynamics. We present a two-stage deep learning model to emulate high-resolution (HR-HydroSim) baryonic fields from…

While cold dark matter is widely supported by a range of cosmological observations, it encounters several difficulties at smaller scales. These issues have prompted the investigation of various alternative dark matter candidates, leaving…

I compare the power spectra of the radiation fields from two recent sets of fully coupled simulations that model cosmic reionization: "Cosmic Reionization On Computers" (CROC) and "Thesan". While both simulations have similar power spectra…

Highly magnified stars ($\mu$ $>$ 100) are now outinely identified as transient events at cosmological distances thanks to microlensing by intra-cluster stars near the critical curves of galaxy clusters. Using the {\it James Webb} Space…

Due to non-zero neutrino rest masses we expect the energy density today in non-relativistic matter, $\omega_{\rm m}$, to be greater than the sum of baryon and cold dark matter densities, $\omega_{\rm cb}$. We also expect the amplitude of…

In the present work we analyze two different models of interaction between dark energy and dark matter, also known as vacuum decay models or $\Lambda(t)$CDM models. In both models, when the $H_0$ parameter is constrained by the Planck…