Search Publications
A Test of Spectroscopic Age Estimates of White Dwarfs Using Wide WD+WD Binaries
Hermes, J. J.; van Saders, Jennifer L.; Tremblay, P. -E. +4 more
White dwarf stars have been used for decades as precise and accurate age indicators. This work presents a test of the reliability of white dwarf total ages when spectroscopic observations are available. We conduct follow-up spectroscopy of 148 individual white dwarfs in widely separated double-white-dwarf (WD+WD) binaries. We supplement the sample…
Modelling the seasonal cycle of Uranus's colour and magnitude, and comparison with Neptune
Pérez-Hoyos, Santiago; Toledo, Daniel; Irwin, Patrick G J +9 more
We present a quantitative analysis of the seasonal record of Uranus's disc-averaged colour and photometric magnitude in Strömgren b and y filters (centred at 467 and 551 nm, respectively), recorded at the Lowell Observatory from 1950 to 2016, and supplemented with HST/WFC3 observations from 2016 to 2022. We find that the seasonal variations of mag…
XMM-Newton-discovered Fast X-ray Transients: host galaxies and limits on contemporaneous detections of optical counterparts
Stern, D.; Bauer, F. E.; Smartt, S. J. +18 more
Extragalactic fast X-ray transients (FXTs) are a class of soft (0.3-10 keV) X-ray transients lasting a few hundred seconds to several hours. Several progenitor mechanisms have been suggested to produce FXTs, including supernova shock breakouts, binary neutron star mergers, or tidal disruptions involving an intermediate-mass black hole and a white …
Constraining the H2 column densities in the diffuse interstellar medium using dust extinction and H I data
Goldsmith, P. F.; Skalidis, R.; Hopkins, P. F. +1 more
Context. Carbon monoxide (CO) is a poor tracer of H2 in the diffuse interstellar medium (ISM), where most of the carbon is not incorporated into CO molecules, unlike the situation at higher extinctions.
Aims: We present a novel, indirect method for constraining H2 column densities (NH2) without empl…
Single-star Warm-Jupiter Systems Tend to Be Aligned, Even around Hot Stellar Hosts: No T eff–λ Dependency
Butler, R. Paul; Quinn, Samuel N.; Rice, Malena +22 more
The stellar obliquity distribution of warm-Jupiter systems is crucial for constraining the dynamical history of Jovian exoplanets, as the warm Jupiters' tidal detachment likely preserves their primordial obliquity. However, the sample size of warm-Jupiter systems with measured stellar obliquities has historically been limited compared to that of h…
Seven white dwarfs with circumstellar gas discs II: tracing the composition of exoplanetary building blocks
Melis, C.; Hodgkin, S.; Rogers, L. K. +8 more
This second paper presents an in-depth analysis of the composition of the planetary material that has been accreted on to seven white dwarfs with circumstellar dust and gas emission discs with abundances reported in Rogers et al. The white dwarfs are accreting planetary bodies with a wide range of oxygen, carbon, and sulphur volatile contents, inc…
Mapping radial abundance gradients with Gaia-ESO open clusters: Evidence of recent gas accretion in the Milky Way disk
Randich, S.; Palla, M.; Matteucci, F. +5 more
Context. Recent evidence from spectroscopic surveys points towards the presence of a metal-poor, young stellar population in the low- α, chemically thin disk. In this context, the investigation of the spatial distribution and time evolution of precise, unbiased abundances is fundamental to disentangle the scenarios of formation and evolution of th…
SpectroTranslator: Deep-neural network algorithm for homogenising spectroscopic parameters
Pancino, E.; Kordopatis, G.; Masseron, T. +8 more
Context. In modern Galactic astronomy, stellar spectroscopy plays a pivotal role in complementing large photometric and astrometric surveys and enabling deeper insights to be gained into the chemical evolution and chemo-dynamical mechanisms at play in the Milky Way and its satellites. Nonetheless, the use of different instruments and dedicated pip…
Automated Chemical Reaction Network Generation and Its Application to Exoplanet Atmospheres
Yang, Jeehyun; Hu, Renyu
With the advent of JWST and the spectroscopic characterization of exoplanet atmospheres in unprecedented detail, there is a demand for more complete pictures of chemical and photochemical reactions and their impacts on atmospheric composition. Traditionally, building reaction networks for (exo)planetary atmospheres involves manually tracking relev…
Cosmic evolution of radio-excess active galactic nuclei in quiescent and star-forming galaxies across 0 < z < 4
Kohno, Kotaro; Daddi, Emanuele; Liu, Daizhong +9 more
Context. Radio-excess active galactic nuclei (radio-AGNs) are essential to our understanding of both the physics of black hole (BH) accretion and the interaction between BHs and host galaxies. Recent deep and wide radio continuum surveys have made it possible to study radio-AGNs down to lower luminosities and up to higher redshifts than previous s…