NuSTAR and INTEGRAL Observations of a Low/Hard State of 1E1740.7-2942
- Creators
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Natalucci, Lorenzo
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Tomsick, John A.
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Bazzano, Angela
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Smith, David M.
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Bachetti, Matteo
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Barret, Didier
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Boggs, Steven E.
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Christensen, Finn E.
- Craig, William W.
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Fiocchi, Mariateresa
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Fürst, Felix
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Grefenstette, Brian W.
- Hailey, Charles J.
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Harrison, Fiona A.
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Krivonos, Roman
- Kuulkers, Erik
- Miller, Jon M.
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Pottschmidt, Katja
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Stern, Daniel
- Ubertini, Pietro
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Walton, Dominic J.
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Zhang, William W.
Abstract
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.
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).Attached Files
Published - 0004-637X_780_1_63.pdf
Submitted - 1310.7870v1.pdf
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Additional details
- Eprint ID
- 43593
- Resolver ID
- CaltechAUTHORS:20140130-145205686
- NNG08FD60C
- NASA
- NASA/JPL/Caltech
- I/037/12/ 0-011/13
- Agenzia Spaziale Italiana (ASI)
- I/033/10/0
- Agenzia Spaziale Italiana (ASI)
- Centre National d'Études Spatiales (CNES)
- Created
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2014-01-30Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- NuSTAR, Space Radiation Laboratory