Astronomy and Astrophysics

The post-main-sequence evolution of massive stars encompasses phases in which the stars display high variability. One such class of objects are the blue supergiants. These objects may be in either the pre- or post-red-supergiant phase of their evolution. Their variability patterns might provide constraints for a proper classification of the objects. The study aims to characterise the observed var…

Stellar chemical abundances encode the formation and evolutionary history of the Galactic disc. The bimodality observed in the $ α/ Fe -- Fe / H $ plane has been widely interpreted as evidence of distinct thin- and thick-disc populations. We analysed the chemical, spatial, and kinematic properties of stars in the solar neighbourhood using the Dark Energy Spectroscopic Instrument (DESI) Data Relea…

In 2017, the Event Horizon Telescope (EHT) collaboration produced the first image of the M87 black-hole shadow, offering strong observational support for the presence of an event horizon. However, the Difmap pipeline widely used in the early EHT very long baseline interferometry (VLBI) imaging process mainly adopts the point-source-oriented scale-free CLEAN deconvolution method, which has certain…

The composition of rocky planets depends on the dust in their natal protoplanetary disk (PPD), which may contain water ice. Crystalline water ice was detected in the PPD d216-0939 in the Orion Nebula Cluster (ONC). We aim to constrain the spatial distribution and crystallization state of water ice in the d216-0939 disk using recent observations of the water ice absorption feature at a wavelength …

Free-floating planet–moon pairs (FFPMs) may form when planetary systems experience close stellar encounters. We aim to quantify moon-retention probabilities and ejection cross-sections for planets and planet–moon systems subject to close stellar encounters, and to identify the orbital conditions most favorable for forming FFPMs. We conducted extensive numerical scattering experiments to compute e…

The existence of billion-solar-mass quasars at redshifts z ≳ 7 poses a formidable challenge to theories of black hole formation, requiring pathways for the rapid growth of massive seeds. One such pathway may arise from primordial stars powered by dark matter (DM) self-annihilation rather than conventional hydrogen fusion, which could form massive black hole seeds in ordinary cosmological mini-hal…

Recent efforts to characterise the molecular gas content of brightest cluster galaxies (BCGs) at intermediate redshift have revealed a subpopulation of gas-rich systems, whose star formation activity is likely influenced by environmental processing. In this study, we aim to investigate the molecular gas reservoirs and star formation fuelling of central galaxies in groups, also known as brightest …

We analyze the post-perihelion coma of the Great Comet of 2024, C/2023 A3 (Tsuchinshan–ATLAS), to characterize its dust activity and assess the contribution of sublimating icy grains to a candidate near-nucleus halo. Using archival Zwicky Transient Facility images obtained between 15 February and 26 May 2025, we performed aperture photometry within a fixed projected radius of 40,000 km and derive…

Magnetic fields can have an important influence on stellar structure and evolution. In intermediate-mass (A- and F-type) stars, there are many known stars with directly measured strong, globally organized magnetic fields, as well as indications of weak and/or small-scale variable fields. However, among the intermediate-mass γ Dor pulsators, there are no known stars with strong surface magnetic fi…

Highly magnified stars at cosmological distances (z ≳ 0.7) become detectable thanks to microlensing by intracluster stars near the critical curves of galaxy clusters. Multi-epoch photometric campaigns targeting caustic crossing galaxies magnified by massive galaxy clusters enable the detection of these objects as transient events. Such stars provide unique opportunities to study stellar populatio…

Spatially resolved galaxy kinematics have been most extensively studied at z and z>1. The emerging consensus is that disks are common out to z albeit with larger disk velocity dispersions. In this picture, z appears as a key transition in several fundamental aspects, such as the main driver of disk gas turbulence and baryonic-dark matter (DM) mass budget. While at z multi-tracer spatially reso…

Atmospheric escape is considered a key process in shaping exoplanet demographics and evolution. To probe this process observationally, the near-infrared metastable helium triplet (He, at ∼ 10833,Å) has emerged as one of the most powerful tracers of hydrodynamical outflows. In recent years, a large variety of instruments have been used to detect and characterize expanding upper atmospheres. High-r…

We present and investigate the properties of a sample of radio-selected, Euclid-dark galaxies, identified from LOFAR HBA observations at 144,MHz within the Euclid Deep Field-North (EDF-N), covering approximately 10 deg2$. Starting from 1051 radio sources lacking optical counterparts down to a 5σ depth of 23.9 in the y band in previous surveys (but detected with /IRAC), we identified 166 galaxies …

We have developed , a modular, flexible, and efficient end-to-end simulator for submillimetre (submm) integral field units (IFUs) that use kinetic inductance detectors (KIDs). The simulator consists of a Python interface, powered by a C/C++ backend that uses CUDA for GPU-acceleration, and is publicly available and fully open-source. gateau gateau simulates observations by taking user input such a…

For decades, the origin of helium enrichment in O-type stars has remained an open question. We investigate the correlation between surface helium abundance ( ) and orbital parameters for a sample of 45 O-type SB1 systems, including Cyg X-1. We find seven He-rich systems, all of which are concentrated at short orbital periods (P!łesssim!15 days) and are classified as RW. In addition, four of them …

The large-scale structure (LSS) of the Universe is an important probe for deviations from the canonical cosmological constant Λ and cold dark matter (ΛCDM) model. A statistically significant detection of any deviations would signify the presence of a new physics or the breakdown of any number of the underlying assumptions of the standard cosmological model or possible systematic errors in the dat…

Isotopic fractionation can serve as a powerful tracer of chemical evolution during star and planet formation. To accurately interpret observations, it is crucial to identify the dominant pathways of nitrogen and carbon fractionation at different evolutionary stages. We aim to study nitrogen and carbon fractionation in a sample of young cores at the onset of star formation. We mapped H 13 CN and H…

Late infall episodes, where material from the surrounding environment accretes onto Class II protoplanetary disks, are emerging as a potentially important but poorly quantified driver of disk evolution. Observed as filamentary streamers in molecular lines and scattered light, such late-stage accretion can perturb disk structures through localized shocks, density enhancements, and warps, yet its c…

Extended Lyα emission is ubiquitously observed around quasars. This emission traces the cool gas within the circumgalactic medium and provides insights into the complex interplay between gas dynamics and active galactic nucleus feedback. However, its connection to the cold molecular gas of the host galaxies remains largely unexplored. We aim to characterize the molecular gas reservoirs in quasars…

We present a high-resolution hydrodynamical simulation of the formation and evolution of nuclear structures in a Milky Way-mass galaxy using the SMUGGLE model. The system naturally develops a bar in isolation of approx5 kpc in length, driving sustained gas inflows toward the center that lead to the formation of a nuclear stellar disk (NSD) and a nuclear star cluster (NSC). By only considering sta…