宇宙学与河外天体物理

Small scale clumps of ionized gas have been suggested by observations in interstellar medium and circumgalactic medium. The propagation of radio signals can be deflected by these plasma clumps, i.e. plasma lensing. One observable…

Gravitational waves constitute a powerful probe of the underlying theory of gravity. In extensions of general relativity, additional degrees of freedom, such as scalar fields in the gravitational sector, can modify their propagation through…

Interacting dark sector (IDS) models provide a commonly explored extension of the standard $\Lambda$CDM cosmology, allowing for non-gravitational energy--momentum exchange between cold dark matter (CDM) and dark energy (DE). Although such…

We study the early stages of an oscillatory reheating phase in an inflaton plus spectator axion-SU(2) system, including both an axion-gauge Chern-Simons coupling $\chi F\tilde{F}$ and a gravitational Chern-Simons coupling $\chi R\tilde{R}$.…

We investigate the cosmological information in higher-order statistics of the cosmic microwave background (CMB) lensing convergence field for a near-term experiment with noise properties similar to the Simons Observatory (SO). Using a fully…

Gravitational waves (GWs) exhibit wave-optics effects when their wavelength is comparable to the scale of the gravitational lens. This may occur in lensing from galactic subhalos in GWs emitted by binary black-hole mergers, and is gaining…

We present FlowSN, a statistical framework using simulation-based inference (SBI) with normalising flows to account for selection effects in observational astronomy. Failure to account for selection effects can lead to biased inference on…

Observations of Cosmic Microwave Background (CMB) B-mode polarization provide a way to probe primordial gravitational waves and test inflationary predictions. Extragalactic point sources become a major source of contamination after…

The XRISM Resolve X-ray spectrometer allows to gain detailed insight into gas motions of the intra cluster medium (ICM) of galaxy clusters. Current simulation studies focus mainly on statistical comparisons, making the comparison to the…

Future third-generation gravitational wave detectors like the Einstein Telescope (ET) and Cosmic Explorer (CE) are expected to detect millions of binary black hole (BBH) mergers. Alongside these advances, upcoming radio surveys, such as the…

The existence of a radio synchrotron background (RSB) excess is implied by a number of measurements, including excess emission seen by the ARCADE~2 and LWA experiments. Highly sensitive wideband radio arrays, of the kind used to measure the…

Loop corrections to primordial correlation functions are unavoidable due to the non-linear nature of gravity. Previous works have established a robust framework for computing the renormalised one-loop power spectra of scalar and tensor…

The sky localisation of about $10$ to $100~\text{deg}^2$, which is expected to be achieved in all-sky blind searches for gravitational waves from supermassive black hole binaries (SMBHBs) with Pulsar Timing Array (PTA) experiments, has long…

Upcoming weak lensing (WL) surveys such as those by {\it Euclid}, LSST, and {\it Roman} require percent-level control over systematic effects. A common approach to mitigating baryonic effects uses semi-analytic baryon correction models…

We propose a unified scalar-field framework that addresses, within standard general relativity, three current cosmological anomalies: the $H_0$ tension, the mild preference for reduced late-time clustering ($S_8$), and recent indications of…

Fast radio bursts (FRBs) offer a powerful probe of the ionized Universe through their dispersion measures (DM). While a significant fraction of the DM arises from the intergalactic medium (IGM), the contributions from the host galaxy and…

Warm inflation is commonly studied under the assumption that the stochastic force sourcing inflaton fluctuations is Markovian. Realistic thermal systems, however, possess finite relaxation times and can therefore generate colored noise with…

The statistical properties of ionisation structures during the Epoch of Reionisation (EoR) provide valuable insights into the formation of the first stars and galaxies. However, statistics such as size distributions of ionisation structures…

We investigate how perturbative reheating after inflation modifies the primordial gravitational wave (GW) spectrum generated by cosmological phase transitions. Within a specific inflationary setup, we show that the thermodynamic quantities…

We propose a unified framework where the totality of dark matter (DM), the baryon asymmetry of the universe, and a detectable stochastic gravitational wave (GW) background originate from ultra-slow-roll (USR) inflation. The drastic…