Re-awakening of GRS 1716-249 after 23 yr, observed by Swift/XRT and NuSTAR
Bharali P, Chandra S, Chauhan J, Garcia J, Roy J, Boettcher M, Boruah K (2019)
Publication Type: Journal article
Publication year: 2019
Journal
Book Volume: 487
Pages Range: 3150-3161
Journal Issue: 3
Abstract
In this work, we present a spectral and temporal analysis of Swift/XRT and NuSTAR observations of GRS 1716-249 during its recent 2016-2017 outburst. This low-mass X-ray binary underwent an extraordinary outburst after a long quiescence of 23 yr, since its last major outburst in 1993. The source was observed over two different epochs during 2017 April 7 and 10. The best-fitting joint spectral fitting in the energy range 0.5-79.0 keV indicates that the spectrum is best described by relatively cold, weak disc blackbody emission, dominant thermal Comptonization emission, and a relativistically broadened fluorescent iron K alpha emission line. We observed a clear indication of a Compton hump around 30 keV, We also detected an excess feature of 1.3 keV. Assuming a lamp-post geometry of the corona, we constrained the inner disc radius for both observations to 11.92(-11.92)(+8.62) R-ISCO (i.e. an upper limit) and 10.39(-3.02)(+9.51) R-ISCO (where R-ISCO = radius of the innermost stable circular orbit) for the first epoch (El) and second epoch (E2), respectively. A significant (5 sigma) type C quasi-periodic oscillation (QPO) at 1.20 +/- 0.04 Hz is detected for the first time for GRS 1716-249, which drifts to 1.55 +/- 0.04 Hz (6 sigma) at the end of the second observation. The derived spectral and temporal properties show a positive correlation between the QPO frequency and the photon index.
Authors with CRIS profile
Involved external institutions
Tata Institute of Fundamental Research (TIFR)
India (IN)
Noordwes-Universiteit / North-West University
South Africa (ZA)
Gauhati University
India (IN)
University of Mumbai
India (IN)
India (IN)
Noordwes-Universiteit / North-West University
South Africa (ZA)
Gauhati University
India (IN)
University of Mumbai
India (IN)
How to cite
APA:
Bharali, P., Chandra, S., Chauhan, J., Garcia, J., Roy, J., Boettcher, M., & Boruah, K. (2019). Re-awakening of GRS 1716-249 after 23 yr, observed by Swift/XRT and NuSTAR. Monthly Notices of the Royal Astronomical Society, 487(3), 3150-3161. https://doi.org/10.1093/mnras/stz1492
MLA:
Bharali, Priya, et al. "Re-awakening of GRS 1716-249 after 23 yr, observed by Swift/XRT and NuSTAR." Monthly Notices of the Royal Astronomical Society 487.3 (2019): 3150-3161.
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