Institute of Astronomy

Self-interacting dark matter promotes bar formation in disk galaxies

Abstract Despite its remarkable success on large scales, the standard ΛCDM paradigm faces persistent small-scale challenges that have motivated alternative models for the dark sector. Self-interacting dark matter (SIDM) offers a compelling possibility, in which dark matter partic...

The Gravitational-wave Optical Transient Observer (GOTO) Fast Analysis and Spectroscopy of Transients (FAST) Surveys

Abstract The study of young and fast astronomical transients is often limited by the difficulty of acquiring data, particularly spectra, within hours to days of explosion. Historically, follow-up programmes have rarely obtained spectra until many days after discovery; coupled wit...

Small hosts, big appetites: unveiling rapid and early low-mass black hole growth in cosmological zoom-in simulations of dwarf galaxies

Abstract Dwarf galaxies are ideal laboratories to probe the interplay between galaxy formation and the growth of black holes (BHs) in the early Universe. Mounting observational evidence reveals the presence of BHs in low-mass galaxies across cosmic time, with JWST uncovering a li...

Is uniformitarianism still necessary for studying Earth-like planets?

Hutton's uniformitarianism has been an instrumental concept in establishing Earth sciences as a rigorous discipline. However, ever since Gould's famous paper in 1965, we have been wrestling with whether the concept has largely outlived its scientific relevance. Here, I ask this q...

Gas absorption of soft X-rays strongly impacts the redshift distribution of dark Fast X-ray Transients

Abstract The progenitors of many Fast X-ray Transients (FXTs) and those of γ-ray bursts (GRBs) are strongly linked. Given that ”dark” GRBs are typically found to be events suffering from enhanced extinction in the host galaxy, we investigate the nature of ”dark” FXTs. However, un...

Dust Substructures and Line Perturbations driven by a Forming Planet in J16120

Abstract Hints of planet formation have been independently reported within the gap of the disc around 2MASS J16120668-301027 from millimetre continuum, infrared, and Hα observations. In this work, we present new evidence for ongoing planet formation based on Atacama Large Millime...

Slow stellar halo rotation as a signature of disc flips and GES-like mergers

Abstract The stellar halo of the Milky Way (MW) exhibits a weak net prograde rotational signal (vφ ≲ 25 km s−1), yet its origin remains unexplained. To investigate this, we use the Auriga cosmological simulation suite of MW-mass haloes to probe the rotation of stellar haloes over...

Hot blue progenitors of stellar-mass black holes

Abstract While the connection between massive stars and supernova explosions is well established observationally, the link between massive stars and black hole formation remains elusive. Some massive stars may collapse directly to black holes without a successful supernova, and m...

Gravitational instability in planet-forming discs

During the earliest phases of star and planet formation, a young star is surrounded by a disc that can become gravitationally unstable. Indeed, if the protoplanetary disc is sufficiently massive, its self-gravity triggers the formation of large scale spiral arms, transporting ang...

The true masses of radial-velocity exoplanets constrained by stability

Abstract Exoplanets discovered with the radial velocity method suffer from a mass-inclination degeneracy: only the minimum mass Mmin = Msin i is measured. An exoplanet with an Earth-sized minimum mass could actually therefore be a sub-Neptune, or even a gas giant. However, for co...

Flyby-induced high-eccentricity migration and the prevalence of hot Jupiters in M67

Abstract Few planetary systems form in isolation. Rather, interactions in their birth environments may sculpt their architectures or drive them into unstable configurations. Here we study the role of environmental perturbations in triggering dynamical instabilities leading to hot...

From mass-loss histories to lightcurves: a generalised framework for interaction-powered transients

Abstract We introduce a fast (~1–50 ms) and generalised public framework for modelling interaction-powered transients. The framework solves the thin-shell equations of motion for ejecta colliding with circumstellar material (CSM), and supports arbitrary CSM density and velocity p...

Pulsations in Binary Star Systems

High-precision and long-duration light curves from space telescopes have revolutionized the fields of asteroseismology and binary star systems. In particular, the number of pulsating systems in eclipsing binaries has drastically increased thanks to space-based observations coveri...

Measuring masses of transiting Earth-like planets: first insights from the PLATO RV Data Challenge

Abstract The PLATO Stellar Variability Mitigation Working Group designed a radial-velocity (RV) data challenge to assess the precision and accuracy achievable on RV semi-amplitudes in the context of the future PLATO follow-up. Using Sun-as-a-star observations obtained with HARPS-...