Multi-band look at the black hole X-ray transient Swift J1357.2-0933 and discovery of the Millihertz Variability in the X-ray light curves
Abstract
Swift J1357.2-0933 is a black-hole candidate X-ray transient, and several multi-wavelength observations have been made during its outbursts. This source has previously shown intense dips in the optical light curve, a phenomenon linked to the existence of a "unique toroidal structure" in the inner region of the disc, seen at a high inclination. This talk will present the analysis results using X-ray data from the Neil Gehrels Swift, NICER, NuSTAR observatories, and radio data from AMI. A substantial X-ray variability in the X-ray light curves is seen for the first time, structures varying at timescales of ∼200-700s. Millihertz quasi-periodic X-ray oscillations are found in all observations with frequencies varying between ∼ 1-5 mHz. An absorbed power-law model could well describe the broadband spectra without any signatures of the cut-off at energies above 10 keV or any reflection from the disc or the putative torus. Our multi-wavelength study using the data of X-ray telescope and Ultraviolet/Optical Telescope aboard Swift showed a correlation with X-ray measurements, indicating that most of the reprocessed flux must be coming out in the ultraviolet.
- Publication:
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44th COSPAR Scientific Assembly. Held 16-24 July
- Pub Date:
- July 2022
- Bibcode:
- 2022cosp...44.2043B