g/r-band observation of AT 2019wey

DOI

AT2019wey (SRGA J043520.9+552226, SRGE J043523.3+552234) is a transient first reported by the ATLAS optical survey in 2019 December. It rose to prominence upon detection, three months later, by the Spektrum-Roentgen-Gamma (SRG) mission in its first all-sky survey. X-ray observations reported in Yao et al. suggest that AT2019wey is a Galactic low-mass X-ray binary (LMXB) with a black hole (BH) or neutron star (NS) accretor. Here we present ultraviolet, optical, near-infrared, and radio observations of this object. We show that the companion is a short-period (P<~16hr) low-mass (<1M{sun}) star. We consider AT2019wey to be a candidate BH system since its locations on the Lradio-LX and Lopt-LX diagrams are closer to BH binaries than NS binaries. We demonstrate that from 2020 June to August, despite the more than 10 times brightening at radio and X-ray wavelengths, the optical luminosity of AT2019wey only increased by 1.3-1.4 times. We interpret the UV/optical emission before the brightening as thermal emission from a truncated disk in a hot accretion flow and the UV/optical emission after the brightening as reprocessing of the X-ray emission in the outer accretion disk. AT2019wey demonstrates that combining current wide-field optical surveys and SRG provides a way to discover the emerging population of short-period BH LMXB systems with faint X-ray outbursts.

Identifier
DOI http://doi.org/10.26093/cds/vizier.19200120
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/ApJ/920/120
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/920/120
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/920/120
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/ApJ/920/120
Provenance
Creator Yao Y.; Kulkarni S.R.; Burdge K.B.; Caiazzo I.; De K.; Dong D.,Fremling C.; Kasliwal M.M.; Kupfer T.; van Roestel J.; Sollerman J.,Bagdasaryan A.; Bellm E.C.; Cenko S.B.; Drake A.J.; Duev D.A.,Graham M.J.; Kaye S.; Masci F.J.; Miranda N.; Prince T.A.; Riddle R.,Rusholme B.; Soumagnac M.T.
Publisher CDS
Publication Year 2024
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; High Energy Astrophysics; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy