J/ApJ/920/120 g/r-band observation of AT 2019wey (Yao+, 2021)
Multi-wavelength Observations of AT2019wey: a New Candidate Black Hole Low-mass
X-ray Binary.
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.
<Astrophys. J., 920, 120 (2021)>
=2021ApJ...920..120Y 2021ApJ...920..120Y
ADC_Keywords: Stars, double and multiple; Black holes; Photometry, VRI
Keywords: Low-mass x-ray binary stars ; Accretion ; Astrophysical black
holes ; Sky surveys
Abstract:
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☉) 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.
Description:
We constructed the optical light curve using the forced-photometry
services of ZTF; Smith et al. 2020PASP..132h5002S 2020PASP..132h5002S.
Objects:
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RA (2000) DE Designation(s)
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04 35 23.28 +55 22 34.2 AT 2019wey = AT 2019wey
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 25 991 ZTF forced photometry of AT2019wey
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See also:
IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
J/A+A/588/A103 : Second ROSAT all-sky survey source catalog (Boller+, 2016)
J/A+A/593/A68 : PTF12os & iPTF13bvn spectra and light curves (Fremling+, 2016)
J/ApJS/222/15 : WATCHDOG all-sky database of Galactic BHXBs (Tetarenko+, 2016)
J/ApJ/900/46 : UV, opt and IR light curve of supernova SN2019dge (Yao+, 2020)
Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 10 F10.4 d MJD [58206/59184] Modified Julian Date
12- 17 F6.2 uJy Flux [-42.9/466] Flux density in Filter
19- 23 F5.2 uJy e_Flux [1/39] Uncertainty in Flux
25- 25 A1 --- Filt Filter used; g or r
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 27-Feb-2024