Please use this identifier to cite or link to this item:
http://hdl.handle.net/20.500.12386/25874
Title: | The Swift Supergiant Fast X-ray Transients outburst factory | Authors: | ROMANO, Patrizia Kennea, Jamie Barthelmy, Scott Douglas Bozzo, Enrico Burrows, David N. Ducci, Lorenzo ESPOSITO, PAOLO Evans, Phil Gehrels, Neil Krimm, Hans A. VERCELLONE, STEFANO |
Issue Date: | 2016 | First Page: | id. 120.20 | Abstract: | We present the Swift Supergiant Fast X-ray Transients project, which has been exploiting Swift's capabilities in a systematic study of SFXTs and classical supergiant X-ray binaries (SGXBs) since 2007. We performed an efficient long-term monitoring of 16 sources including both SFXTs and classical SGXBs and followed source activity across more than 4 orders of magnitude in X-ray luminosity, sampling the light curves on timescales spanning from few hundred seconds to years. We use our measurements of dynamic ranges, duty cycles as a function of luminosity, and luminosity distributions to highlight systematic differences that help discriminate between different theoretical models proposed to explain the differences between the wind accretion processes in SFXTs and classical SGXBs. Our follow-ups of the SFXT outbursts provide a steady advancement in the comprehension of the mechanisms triggering the high X-ray level emission of these sources. In particular, the recent observations of the outburst of the SFXT prototype IGR J17544-2619 on 2014 October 10, when the source reached a peak luminosity of 3x10<SUP>38</SUP> erg s<SUP>-1</SUP>, challenged, for the first time, the maximum theoretical luminosity achievable by a wind-fed neutron star high mass X-ray binary. We propose that this giant outburst was due to the formation of a transient accretion disc around the compact object. | Note: | We present the Swift Supergiant Fast X-ray Transients project, which has been exploiting Swift's capabilities in a systematic study of SFXTs and classical supergiant X-ray binaries (SGXBs) since 2007. We performed an efficient long-term monitoring of 16 sources including both SFXTs and classical SGXBs and followed source activity across more than 4 orders of magnitude in X-ray luminosity, sampling the light curves on timescales spanning from few hundred seconds to years. We use our measurements of dynamic ranges, duty cycles as a function of luminosity, and luminosity distributions to highlight systematic differences that help discriminate between different theoretical models proposed to explain the differences between the wind accretion processes in SFXTs and classical SGXBs. Our follow-ups of the SFXT outbursts provide a steady advancement in the comprehension of the mechanisms triggering the high X-ray level emission of these sources. In particular, the recent observations of the outburst of the SFXT prototype IGR J17544-2619 on 2014 October 10, when the source reached a peak luminosity of 3x1038 erg s-1, challenged, for the first time, the maximum theoretical luminosity achievable by a wind-fed neutron star high mass X-ray binary. We propose that this giant outburst was due to the formation of a transient accretion disc around the compact object. | Conference Name: | American Astronomical Society, High Energy Astrophysics Division (HEAD) Meeting #15 | Conference Place: | Naples, Florida, USA | Conference Date: | April 3-7, 2016 | URI: | http://hdl.handle.net/20.500.12386/25874 | Bibcode ADS: | 2016HEAD...1512020R | Fulltext: | open |
Appears in Collections: | 4.09 Prodotti multimediali |
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romanop_sfxts_poster_head16.pdf | poster | 1.62 MB | Adobe PDF | View/Open |
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