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Re-awakening of GRS 1716–249 after 23 yr, observed by Swift/XRT and NuSTAR

Bharali, Priya and Chandra, Sunil and Chauhan, Jaiverdhan and García, Javier A. and Roy, Jayashree and Boettcher, Markus and Boruah, Kalyanee (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). pp. 3150-3161. ISSN 0035-8711. doi:10.1093/mnras/stz1492.

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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 α 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^(+8.62)_(−11.92) R_(ISCO) (i.e. an upper limit) and 10.39^(+9.51)_(−3.02) R_(ISCO)(where R_(ISCO) ≡ radius of the innermost stable circular orbit) for the first epoch (E1) and second epoch (E2), respectively. A significant (5σ) 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 (6σ) 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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Chandra, Sunil0000-0002-8776-1835
Chauhan, Jaiverdhan0000-0003-0330-1901
García, Javier A.0000-0003-3828-2448
Roy, Jayashree0000-0002-2329-5863
Additional Information:© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model ( Accepted 2019 May 28. Received 2019 May 28; in original form 2017 July 18. Published: 04 June 2019. This research has made use of the software and/or data obtained through the High Energy Astrophysics Science Archive Research Center (HEASARC) online service, provided by the NASA/Goddard Space Flight Center and the SWIFT data center. We thank NuSTAR team for making NuSTAR data public. MAXI data are obtained from MAXI team, RIKEN, JAXA. The authors gratefully acknowledge the anonymous referee for constructive comments that improved the paper. The authors are also thankful to PI’s for proposing these observations. JC and SC are also grateful to Prof. H. M. Antia, Prof. A. R. Rao, and Prof. S. Bhattacharyya for constructive discussions about diagnostics and interpretations. The work by MB is supported by the Department of Science and Technology and National Research Foundation (NRF) of South Africa through the South African Research Chairs Initiative (SARChI), grant no. 64789. SC acknowledges the supports by CSR-NWU and NRF.
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
Department of Science and Technology (South Africa)UNSPECIFIED
National Research Foundation (South Africa)UNSPECIFIED
South African Research Chairs Initiative (SARChI)64789
North-West University PotchefstroomUNSPECIFIED
Subject Keywords:accretion, accretion discs – black hole physics –X-rays: binaries – X-rays: individual: GRS 1716–249
Issue or Number:3
Record Number:CaltechAUTHORS:20190816-075233072
Persistent URL:
Official Citation:Priya Bharali, Sunil Chandra, Jaiverdhan Chauhan, Javier A García, Jayashree Roy, Markus Boettcher, Kalyanee Boruah, Re-awakening of GRS 1716–249 after 23 yr, observed by Swift/XRT and NuSTAR, Monthly Notices of the Royal Astronomical Society, Volume 487, Issue 3, August 2019, Pages 3150–3161,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97935
Deposited By: Tony Diaz
Deposited On:16 Aug 2019 16:43
Last Modified:16 Nov 2021 17:35

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