宇宙学与河外天体物理
Upcoming stage 4 surveys, such as the Simons Observatory, LSST, and Euclid, are poised to measure weak gravitational lensing of the Cosmic Microwave Background (CMB) and galaxies with unprecedented precision. While the power spectrum is the…
Analyses by the Dark Energy Spectroscopic Instrument (DESI) collaboration suggest a significant deviation from the $\Lambda$CDM model when their baryon acoustic oscillation (BAO) measurements are combined with Planck cosmic microwave…
Modeling the intrinsic alignment (IA) of galaxies poses a challenge to weak lensing analyses. The Dark Energy Survey is expected to be less impacted by IA when limited to blue, star-forming galaxies. The cosmological parameter constraints…
We present new constraints on the local-type primordial non-Gaussianity parameter, $f_\mathrm{NL}^\mathrm{local}$, through analysis of the scale-dependent bias effect on the cosmic infrared background (CIB). To avoid biases from galactic…
We present VERSUS, a publicly available, fast void-finding algorithm designed to identify spherical underdensities in the density field that can be accurately described by excursion set predictions of the void size function. We validate the…
We compute the thermal activation rate of metastable self-gravitating Bose-Einstein condensates with attractive self-interaction (e.g., dilute axion stars) by using the instanton theory. Explicit analytical results are given close to the…
JWST's discovery of unexpectedly bright $z>10$ galaxies has triggered claims that standard $\Lambda$CDM cannot reproduce their abundances, while estimates of the ionizing escape fraction $f_{\rm esc}$ at $z>6$ have spanned a factor of four…
We present the first end-to-end validation of the Euclid baryon acoustic oscillation (BAO) analysis pipeline, encompassing density-field reconstruction, two-point correlation function measurement, and cosmological-parameter inference. Using…
The amplitude of the detected stochastic gravitational wave background (SGWB) measured by pulsar timing arrays (PTAs) and the discovery of early and over-massive central black holes at high redshift by the James Webb Space Telescope (JWST)…
Higher-order correlation functions are firmly established as a fundamental tool for the statistical analysis of clustering in modern galaxy surveys. It was demonstrated that they greatly enrich the information content extracted by two-point…
We present a hemispherical comparison analysis of the deceleration parameter $q_0$ using the Pantheon+ sample of Type Ia supernovae to test the isotropy of cosmic acceleration and the robustness of redshift corrections. We detect…
Galaxy clusters are the most massive gravitationally bound structures in the Universe and key probes of cosmic evolution. The large data volume expected from upcoming surveys requires efficient automated analysis methods for tens of…
Gravitational microlensing constraints on non-standard compact objects are conventionally derived assuming lenses trace the dark matter halo with velocities following a Maxwell-Boltzmann distribution centered around $10^{-3}c$. However, a…
Fast Radio Bursts (FRBs) are among the most intriguing phenomena observed in radio astronomy. So far, about 130 FRB signals have been confirmed and characterized by different surveys, and the CHIME telescope has recently reported a new…
We study binary mergers of dark matter cores in the Bose-Einstein condensate (BECDM) model. We include two scenarios: scalar self-interaction and the presence of a gravitationally coupled ideal gas. Using 3D simulations of the…
Stupendously large astrophysical black holes (SLABs) are hypothetical black holes with masses of more than a trillion Suns. Because observable consequences of their existence have only recently been seriously considered, there have been…
We present an analysis comparing nulling strategies for reducing the impact of baryon feedback on cosmic shear measurements. We consider three different approaches which aim to `null' the high-$k$ modes using transformations applied to the…
We construct samples of optically-selected clusters and photometric luminous red galaxies (LRGs) from the Hyper Suprime-Cam Subaru Strategic Program final year dataset covering $\sim 1200$~deg$^2$. The cluster catalogs extend out to the…
We present a new method to constrain local primordial non-Gaussianity using the large-scale modulation of the local lensing power spectrum. Our work extends our recently proposed $\pi$-field method for primordial non-Gaussianity estimation…
Local Primordial non-Gaussianities (PNGs), characterized by $f_{\rm NL}^{\rm loc}$, provide a powerful window into the physics of inflation. Cross-correlating high-redshift tracer samples with the CMB lensing potential offers a particularly…