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Two Lensed Star Candidates at z ≃ 4.8 behind the Galaxy Cluster MACS J0647.7+7015
Mahler, Guillaume; Donahue, Megan; Broadhurst, Tom +26 more
We report the discovery of two extremely magnified lensed star candidates behind the galaxy cluster MACS J0647.7+015 using recent multiband James Webb Space Telescope (JWST) NIRCam observations. The star candidates are seen in a previously known, z phot ≃ 4.8 dropout giant arc that straddles the critical curve. The candidates lie near t…
Spectroscopic age estimates for APOGEE red-giant stars: Precise spatial and kinematic trends with age in the Galactic disc
Schultheis, M.; Casamiquela, L.; Anders, F. +12 more
Over the last few years, many studies have found an empirical relationship between the abundance of a star and its age. Here we estimate spectroscopic stellar ages for 178 825 red-giant stars observed by the APOGEE survey with a median statistical uncertainty of 17%. To this end, we use the supervised machine learning technique XGBoost, trained on…
XRBcats: Galactic High Mass X-ray Binary Catalogue★
Santangelo, A.; Doroshenko, V.; Avakyan, A. +1 more
Context. We present a new catalogue of high mass X-ray binaries (HMXBs) in the Galaxy that we call the Galactic High Mass X-ray Binary Catalogue (XRBcats), which improves upon the most recent of such catalogues. We include new HMXBs discovered since previous publications and revise the classification for several objects previously considered HMXBs…
Alive and kicking: A new QPE phase in GSN 069 revealing a quiescent luminosity threshold for QPEs
Read, A. M.; Miniutti, G.; Kara, E. +4 more
X-ray quasi-periodic eruptions (QPEs) are intense repeating soft X-ray bursts from the nuclei of nearby galaxies. Their physical origin is still largely unconstrained, and several theoretical models have been proposed ranging from disc instabilities to impacts between an orbiting companion and the existing accretion disc around the primary, or epi…
Hubble Space Telescope survey of Magellanic Cloud star clusters. Photometry and astrometry of 113 clusters and early results
Di Criscienzo, M.; Wang, C.; Milone, A. P. +29 more
In the past few years, we have undertaken an extensive investigation of star clusters and their stellar populations in the Large and Small Magellanic Clouds (LMC and SMC) based on archival images collected with the Hubble Space Telescope. We present photometry and astrometry of stars in 101 fields observed with the Wide Field Channel of the Advanc…
An observed population of intermediate-mass helium stars that have been stripped in binaries
Smith, N.; de Mink, S. E.; Drout, M. R. +4 more
The hydrogen-rich outer layers of massive stars can be removed by interactions with a binary companion. Theoretical models predict that this stripping produces a population of hot helium stars of ~2 to 8 solar masses (M☉), however, only one such system has been identified thus far. We used ultraviolet photometry to identify potential st…
The JWST Resolved Stellar Populations Early Release Science Program. II. Survey Overview
Cooper, M. C.; Gennaro, Mario; McQuinn, Kristen B. W. +39 more
We present the JWST Resolved Stellar Populations Early Release Science (ERS) program. We obtained 27.5 hr of NIRCam and NIRISS imaging of three targets in the Local Group (Milky Way globular cluster M92, ultrafaint dwarf galaxy Draco II, and star-forming dwarf galaxy WLM), which span factors of ~105 in luminosity, ~104 in dis…
Direct imaging discovery of a super-Jovian around the young Sun-like star AF Leporis
De Rosa, Robert J.; Nielsen, Eric L.; Hirsch, Lea A. +5 more
Context. Expanding the sample of directly imaged companions to nearby, young stars that are amenable to detailed astrometric and spectroscopic studies is critical for the continued development and validation of theories of their evolution and atmospheric processes.
Aims: The recent release of the Gaia astrometric catalog allows us to efficien…
Accretion geometry of the neutron star low mass X-ray binary Cyg X-2 from X-ray polarization measurements
Antonelli, L. A.; Costa, E.; Bianchi, S. +92 more
We report spectro-polarimetric results of an observational campaign of the bright neutron star low-mass X-ray binary Cyg X-2 simultaneously observed by IXPE, NICER, and INTEGRAL. Consistently with previous results, the broad-band spectrum is characterized by a lower-energy component, attributed to the accretion disc with kTin ≈ 1 keV, p…
The First JWST Spectrum of a GRB Afterglow: No Bright Supernova in Observations of the Brightest GRB of all Time, GRB 221009A
Le Floc'h, E.; D'Avanzo, P.; Campana, S. +57 more
We present James Webb Space Telescope (JWST) and Hubble Space Telescope (HST) observations of the afterglow of GRB 221009A, the brightest gamma-ray burst (GRB) ever observed. This includes the first mid-IR spectra of any GRB, obtained with JWST/Near Infrared Spectrograph (0.6-5.5 micron) and Mid-Infrared Instrument (5-12 micron), 12 days after the…