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NuSTAR and INTEGRAL Observations of a Low/Hard State of 1E1740.7-2942

Natalucci, Lorenzo and Tomsick, John A. and Bazzano, Angela and Smith, David M. and Bachetti, Matteo and Barret, Didier and Boggs, Steven E. and Christensen, Finn E. and Craig, William W. and Fiocchi, Mariateresa and Fürst, Felix and Grefenstette, Brian W. and Hailey, Charles J. and Harrison, Fiona A. and Krivonos, Roman and Kuulkers, Erik and Miller, Jon M. and Pottschmidt, Katja and Stern, Daniel and Ubertini, Pietro and Walton, Dominic J. and Zhang, William W. (2014) NuSTAR and INTEGRAL Observations of a Low/Hard State of 1E1740.7-2942. Astrophysical Journal, 780 (1). Art. No. 63. ISSN 0004-637X. doi:10.1088/0004-637X/780/1/63.

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The microquasar 1E1740.7-2942, also known as the "Great Annihilator," was observed by NuSTAR in the summer of 2012. We have analyzed in detail two observations taken ~2 weeks apart, for which we measure hard and smooth spectra typical of the low/hard state. A few weeks later the source flux declined significantly. Nearly simultaneous coverage by INTEGRAL is available from its Galactic Center monitoring campaign lasting ~2.5 months. These data probe the hard state spectrum from 1E1740.7-2942 before the flux decline. We find good agreement between the spectra taken with IBIS/ISGRI and NuSTAR, with the measurements being compatible with a change in flux with no spectral variability. We present a detailed analysis of the NuSTAR spectral and timing data and upper limits for reflection of the high energy emission. We show that the high energy spectrum of this X-ray binary is well described by thermal Comptonization.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Natalucci, Lorenzo0000-0002-6601-9543
Tomsick, John A.0000-0001-5506-9855
Bazzano, Angela0000-0002-2017-4396
Smith, David M.0000-0002-0542-5759
Bachetti, Matteo0000-0002-4576-9337
Barret, Didier0000-0002-0393-9190
Boggs, Steven E.0000-0001-9567-4224
Christensen, Finn E.0000-0001-5679-1946
Fiocchi, Mariateresa0000-0001-5697-6019
Fürst, Felix0000-0003-0388-0560
Grefenstette, Brian W.0000-0002-1984-2932
Harrison, Fiona A.0000-0003-2992-8024
Krivonos, Roman0000-0003-2737-5673
Pottschmidt, Katja0000-0002-4656-6881
Stern, Daniel0000-0003-2686-9241
Walton, Dominic J.0000-0001-5819-3552
Zhang, William W.0000-0002-1426-9698
Additional Information:© 2014 American Astronomical Society. Received 2013 September 2; accepted 2013 October 29; published 2013 December 12. This work was supported under NASA contract No. NNG08FD60C, and made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. We thank the NuSTAR Operations, Software and Calibration teams for support with the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). L.N. wishes to acknowledge the Italian Space Agency (ASI) for financial support by ASI/INAF grants I/037/12/ 0-011/13 and I/033/10/0 and the engineering support of M. Federici for setup and maintenance of the INTEGRAL archive and Data Analysis Software at IAPS. M.B. wishes to acknowledge the support from the Centre National d’Etudes Spatiales (CNES).
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
Agenzia Spaziale Italiana (ASI)I/037/12/ 0-011/13
Agenzia Spaziale Italiana (ASI)I/033/10/0
Centre National d’Études Spatiales (CNES)UNSPECIFIED
Subject Keywords:accretion, accretion disks; black hole physics; X-rays: binaries; X-rays: individual (1E 1740.7-2942)
Issue or Number:1
Record Number:CaltechAUTHORS:20140130-145205686
Persistent URL:
Official Citation:NuSTAR and INTEGRAL Observations of a Low/Hard State of 1E1740.7-2942 Lorenzo Natalucci et al. 2014 ApJ 780 63
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:43593
Deposited By: Ruth Sustaita
Deposited On:30 Jan 2014 23:31
Last Modified:10 Nov 2021 16:40

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