Abstract
X-ray bursters are neutron stars in low mass X-ray binaries where hydrogen and/or helium
accretes on the surface, and explodes in recurrent thermonuclear runaways. Such type I X-ray
bursts, characterized by a black-body emission, generally display a fast rise time followed by
an exponential cooling decay of a few seconds to a couple of minutes. However, some rare
bursts, called superbursts, last several hours and release about 1000 times more energy, and
some other intermediate bursts have occasionally been observed with decays of a few tens of
minutes. The superbursts are thought to arise from carbon shell flashes in the layers below the
surface of the neutron star, while the intermediately long bursts are generally explained by the
unstable burning of a thick atmospheric layer of pure helium.
On February 13, 2011, the Danish-built X-ray monitor JEM-X onboard the INTEGRAL
satellite observed for the first time a superburst, which occurred from the Galactic bulge lowmass
X-ray binary SAX J1747.0-2853. This event is also noticeable in light-curves from the
MAXI all-sky monitor onboard the International Space Station. Three days earlier, a flare at
GeV energy was detected by the Fermi/LAT instrument from a position consistent with SAX
J1747.0-2853, marking the beginning of a new outburst from this transient X-ray source.
This talk will present the JEM-X data, showing that the superburst is immediately preceded
by a 30 minute long burst. This exceptional sequence of events makes this first superburst
ever observed from SAX J1747.0-2853 a very peculiar one. In particular, we will discuss the
possibility for the intermediate long burst to act as a firestarter for the superburst.
Original language | English |
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Publication date | 2011 |
Publication status | Published - 2011 |
Event | Dansk Fysisk Selskab årsmøde - Nyborg, Denmark Duration: 1 Jan 2011 → … |
Conference
Conference | Dansk Fysisk Selskab årsmøde |
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City | Nyborg, Denmark |
Period | 01/01/2011 → … |