Search Publications
Asteroseismic age estimate of the open cluster NGC 6866 using Kepler and Gaia
Grundahl, F.; Tailo, M.; Stello, D. +10 more
Context. Asteroseismic investigations of solar-like oscillations in giant stars allow for the derivation of their masses and radii. For members of open clusters, this allows us to obtain an age estimate of the cluster that is expected to be identical to the age estimate given by the colour-magnitude diagram, but independent of the uncertainties th…
An intense narrow equatorial jet in Jupiter's lower stratosphere observed by JWST
de Pater, Imke; Wong, Michael H.; Fletcher, Leigh N. +18 more
The atmosphere of Jupiter has east-west zonal jets that alternate as a function of latitude as tracked by cloud motions at tropospheric levels. Above and below the cold tropopause at ~100 mbar, the equatorial atmosphere is covered by hazes at levels where thermal infrared observations used to characterize the dynamics of the stratosphere lose part…
A transiting brown dwarf in a 2 hour orbit
El-Badry, Kareem; Burdge, Kevin B.; Rodriguez, Antonio C. +1 more
We report the discovery of ZTF J2020+5033, a high-mass brown dwarf (BD) transiting a low-mass star with an orbital period of 1.90 hours. Phase-resolved spectroscopy, optical and infrared light curves, and precise astrometry from Gaia allow us to constrain the masses, radii, and temperatures of both components with few-percent precision. We infer a…
A Census of Near-UV M-dwarf Flares Using Archival GALEX Data and the gPHOTON2 Pipeline
Shvartzvald, Yossi; Perdelwitz, Volker; Ben-Ami, Sagi +1 more
M-dwarfs are common stellar hosts of habitable-zone exoplanets. Near-UV (NUV) radiation can severely impact the atmospheric and surface conditions of such planets, making the characterization of NUV flaring activity a key aspect in determining habitability. We use archival data from the Galaxy Evolution Explorer (GALEX) and XMM-Newton telescopes t…
Where are the missing symbiotic stars? Uncovering hidden symbiotic stars in public catalogues
Akras, Stavros
Theoretical predictions of the population of Galactic symbiotic stars (SySts) are highly inconsistent with the current known population. Despite intense effort over the past decades, observations are still far below the predictions. The majority of known SySts so far are identified based on selection criteria established in the optical regime. The…
Detecting dark compact objects in Gaia DR4: A data analysis pipeline for transient astrometric lensing searches
Kongsore, Marius; Chen, I. -Kai; Tilburg, Ken Van
The Gaia satellite is cataloging the astrometric properties of an unprecedented number of stars in the Milky Way with extraordinary precision. This provides a gateway for conducting extensive surveys of transient astrometric lensing events caused by dark compact objects. In this work, we establish a data analysis pipeline capable of searching for …
Peeking beneath the precision floor - II. Probing the chemo-dynamical histories of the potential globular cluster siblings, NGC 288 and NGC 362
Belokurov, Vasily; Buder, Sven; Monty, Stephanie +8 more
The assembly history of the Milky Way (MW) is a rapidly evolving subject, with numerous small accretion events and at least one major merger proposed in the MW's history. Accreted alongside these dwarf galaxies are globular clusters (GCs), which act as spatially coherent remnants of these past events. Using high precision differential abundance me…
On the origin of UV-dim stars: a population of rapidly rotating shell stars?
Martocchia, S.; Bastian, N.; Saracino, S. +1 more
The importance of stellar rotation in setting the observed properties of young star clusters has become clearer over the past decade, with rotation being identified as the main cause of the observed extended main sequence turn-off (eMSTO) phenomenon and split main sequences. Additionally, young star clusters are observed to host large fractions of…
Contrasting X-ray/UV time-lags in Seyfert 1 galaxies NGC 4593 and NGC 7469 using AstroSat observations
Papadakis, I. E.; Singh, K. P.; Dewangan, G. C. +6 more
We study accretion disc-corona connection in Seyfert 1 galaxies using simultaneous UV/X-ray observations of NGC 4593 (2016 July 14-18) and NGC 7469 (2017 October 15-19) performed with AstroSat. We use the X-ray (0.5-7.0 keV) data acquired with the Soft X-ray Telescope (SXT) and the UV (FUV: 130-180 nm, NUV: 200-300 nm) data obtained with the Ultra…
A high-resolution study of near-IR diffuse interstellar bands, search for small-scale structure, time variability, and stellar features
Smoker, J. V.; Evans, C. J.; Boffin, H. M. J. +13 more
Context. The diffuse interstellar bands (DIBs) are a set of hundreds of unidentified absorption features that appear almost ubiquitously throughout the interstellar medium. Most DIBs appear at optical wavelengths, but some are in the near-infrared.
Aims: We aim to characterise near-infrared DIBs at high spectral resolving power towards multip…