宇宙学与河外天体物理

We propose close binary polarimetry as a probe of birefringence induced by ultralight axion dark matter. In a close binary, reflection or scattering can generate a small linear polarization whose time dependence is locked to the orbital…

The possible interaction between dark matter and dark energy has been proposed as a mechanism to alleviate the coincidence problem and the Hubble tension. Strong gravitational lensing observations provide valuable constraints to test the…

We perform the first $k$-cut cosmic shear analysis of the KiDS-Legacy survey. This method uses the Bernardeau-Nishimichi-Taruya (BNT) transform to construct weak-lensing kernels that are more localised than conventional ones, and remove…

Galaxy groups and clusters trace the large-scale matter distribution, with their clustering usually interpreted mainly as a function of halo mass. Yet, at fixed mass, their baryonic properties retain information about halo growth, gas…

We measure the Hubble constant $H_0$ using 13 gravitational-wave binary black hole mergers associated with active galactic nucleus hosts. We find $H_0=70.50^{+3.37}_{-2.89}\,({\rm stat})\pm1.56\,({\rm cal})$\,km\,s$^{-1}$\,Mpc$^{-1}$…

The Hubble tension has come to stay as a major problem in modern cosmology as it continues to plague the standard cosmological model ($\Lambda$CDM). As one of the viable, self-consistent dark energy theories, k-essence involves nontrivial…

We study inflation in metric-affine gravity. We write an action that contains all the second order algebraic distortion terms, and all first order distortion terms with a single covariant derivative, coupled to a scalar field. We include…

Pulsar timing arrays (PTAs) can detect dark matter (DM) substructure through the small shifts a transiting DM subhalo imprints on pulse arrival times. Recently found evidence for a stochastic gravitational-wave background (GWB) acts as red…

We present a field-level inference framework for testing gravity with the large-scale structure that exploits the full information content of the galaxy distribution. Traditional analyses based on the power spectrum discard non-Gaussian and…

The strength of the 21-cm Cosmic Dawn radio absorption signature against the Cosmic Microwave Background or against a bright background radio source depends on the temperature of the neutral hydrogen in the intergalactic medium. While…

Context. Several author have studied the giant radio source GRS0917 + 75 , but its origin remains unclear. Aims. This source is unusual, because of its large size and its location outside a rich cluster of galaxies. We aim to understand and…

High-redshift massive black-hole binary (MBHB) mergers provide a probe of black-hole seed formation and early galaxy assembly, but the population detected by LISA can be modified by galaxy-scale strong lensing. We quantify this effect for…

We present a methodology to measure the intrinsic alignment (IA) signal of galaxies in the vicinity of cosmic voids using the \Euclid-like Flagship cosmological simulation from the Euclid Consortium. The IA signal is quantified and compared…

The redshifted spectral emission from neutral hydrogen (HI) at rest wavelength 21 cm can be used as a tracer of large-scale structure and its evolution. Within the HI intensity mapping method, sufficient signal-to-noise is achieved by…

Recent DESI observations have posed new challenges to $\Lambda$CDM, showing a preference for dynamical dark energy and yielding neutrino mass constraints within $\Lambda$CDM that approach the lower bound allowed by neutrino oscillation…

Supermassive black holes (SMBHs) powering quasars at $z \gtrsim 6$ are difficult to grow from stellar mass remnants, motivating seeds from primordial black holes (PBHs) with masses $10^5-10^7 M_{\odot}$. This range is constrained by the…

We present the construction and characterization of a multi-wavelength catalog of galaxy groups and clusters by matching optical detections from the Southern Photometric Local Universe Survey (S-PLUS) with extended X-ray emission from the…

Within the framework of the Southern Photometric Local Universe Survey (S-PLUS), we introduce ${\bf S}$-PLUS ${\bf C}$lusters ${\bf A}$nd ${\bf L}$arge-scale ${\bf E}$nvironments (SCALE), a project dedicated to the study of galaxy clusters,…

We have made measurements of the difference between the position angle (PA) on the sky and the polarization position angle (PPA) of radio sources using data from a combination of the Radio Fundamental Catalogue (RFC) across a range of…

Context. Protoclusters of galaxies are the earliest phase in the assembly of galaxy clusters and can provide invaluable information about plasma physics, cosmic magnetism, and cosmology. However, due to small angular sizes and cosmological…