130 research outputs found
Using optical spectroscopy to map the geometry and structure of the irradiated accretion discs in low-mass X-ray binaries:the pilot study of MAXI J0637-430
The recurring transient outbursts in low-mass X-ray binaries (LMXBs) provide
us with strong test-beds for constraining the poorly understood accretion
process. While impossible to image directly, phase-resolved spectroscopy can
provide a powerful diagnostic to study their highly complex, time-dependent
accretion discs. We present an 8-month long multi-wavelength (UV, optical,
X-ray) monitoring campaign of the new candidate black hole LMXB MAXI
J0637430 throughout its 2019/2020 outburst, using the {\em Neil Gehrels
Swift Observatory}, as well as three quasi-simultaneous epochs of Gemini/GMOS
optical spectroscopy. We find evidence for the existence of a correlation
between the X-ray irradiation heating the accretion disc and the evolution of
the He {\sc ii} 4686 \AA emission line profiles detected in the optical
spectra. Our results demonstrate a connection between the line emitting regions
and physical properties of the X-ray irradiation heating the discs during
outburst cycles of LMXBs. Further, we are able to show that changes in the
physical properties of the irradiation heating the disc in outburst can be
imprinted within the H/He emission line profiles themselves in these systems.Comment: 23 pages (including 3 appendices), 10 figures, supplementary figures
included in the appendices, accepted for publication in MNRA
ATCA radio detection of the new X-ray transient MAXI J1813-095 as a candidate radio-quiet black hole X-ray binary
We observed the new X-ray transient MAXI J1813-095 (ATels #11323, #11326, #11332) with the Australia Telescope Compact Array (ATCA) between 2018-02-22 20:52 UT and 2018-02-23 02:59 UT. Our observations were taken simultaneously at 5.5 and 9 GHz, with a bandwidth of 2 GHz at each frequency
Rapidly Evolving Disk-Jet Coupling during Re-brightenings in the Black Hole Transient MAXI J1535-571
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