宇宙学与河外天体物理

Non-standard inflationary models often predict oscillatory features in the primordial power spectrum. We present constraints on general oscillatory templates for primordial power spectra, including those that vary linearly and…

We present a catalogue of 131 compact $(\lesssim 0.1 \,arcsec)$ sources detected at 823 MHz via their Interplanetary Scintillation (IPS). These measurements were made with the ASKAP telescope, across its full field of view of 35 square…

The curvaton provides a simple mechanism for generating strongly non-Gaussian curvature perturbations after inflation, with potentially important consequences on small scales. We study curvaton dynamics beyond the standard quadratic…

We show the conservation of the superhorizon curvature perturbations at one-loop level in spatially-flat gauge, including contributions from loop wavenumbers on all scales. In contrast to previous works, we do not assume a hierarchy $k \gg…

The Stage IV cosmological surveys, such as Euclid, LSST, DESI, and SKA, will deliver observational data of unprecedented volume, calling for efficient and reliable inference tools. This paper presents HIcosmo (High-performance Inference for…

We present a comprehensive forecasting framework to assess the detection of primordial oscillatory features by exploiting the synergy between future neutral hydrogen (HI) intensity mapping (IM) surveys and cosmic microwave background (CMB)…

We report a numerical discovery that in a more rapidly accelerating spacetime, the galactic halos on void surfaces develop stronger perpendicular alignments with the directions toward the void centers. We utilize the halo catalogs from the…

Cross-correlations between the thermal Sunyaev-Zel'dovich (tSZ) effect and galaxy surveys provide a sensitive probe of hot gas in low-mass halos, but on the angular scales of greatest astrophysical interest they are also highly vulnerable…

Cosmological observations are placing increasingly stringent bounds on the sum of neutrino masses, approaching the lower limits implied by neutrino oscillation experiments. Recent studies have suggested that dynamical dark energy may…

Within single-field inflation, primordial black hole and scalar-induced gravitational wave production from enhanced primordial perturbations typically requires a transient non-attractor phase, such as ultra-slow roll. We investigate the…

In this series of lectures, we seek to describe the evolution of the cosmic large-scale structure. We will discover the cosmic web - the large-scale skeleton of matter traced by galaxies. It arises from the interplay of the gravitational…

Precision cosmology assumes that cosmic reionization was a single smooth transition. We show that this assumption is in tension with current observations: the Planck optical depth, patchy kinetic Sunyaev--Zel'dovich (PkSZ)limits from SPT…

The Square Kilometre Array's low frequency telescope (SKA-Low) will enable inference of astrophysical and cosmological parameters from the redshifted 21 cm signal, probing the Cosmic Dawn and Epoch of Reionisation. While the power spectrum…

Fast radio bursts (FRBs) are brief, coherent radio pulses of extragalactic origin. They typically last from microseconds to milliseconds and have energies large enough to be visible over cosmological distances. Since FRBs interact with free…

The unprecedented statistical power of galaxy cluster catalogs from the SRG (Spectrum Roentgen Gamma)/eROSITA All-Sky Survey provides a unique opportunity to place stringent constraints on cosmological models through measurements of…

Three-form fields provide a theoretically well-motivated framework for dark energy, arising in higher-dimensional theories and exhibiting a rich cosmological phenomenology. We investigate a minimally coupled three-form dark energy model…

The gravitational-wave sky is expected to contain a rich variety of sources across a very broad range of frequencies. Much like in electromagnetic astronomy, exploring new gravitational-wave frequency bands therefore has the potential to…

We construct an explicit boundary-action realization of superoscillatory initial states (SIS) for inflation, in which quantum interference within a band-limited initial wavefunctional generates a spectrally localized Bogoliubov excitation…

Galaxy redshift surveys encode a wealth of information generated by nonlinear gravitational evolution, galaxy bias, and redshift-space distortions, only part of which is accessible through standard two-point statistics. Motivated by the…

The existence of a landscape of metastable vacua raises the possibility that our Universe may have undergone quantum vacuum decay at late times. This work explores how such a transition can be tested with cosmological observables, focusing…