Abstract
We investigate the thermonuclear bursting behaviour of IGR J17473-2721, an X-ray transient
that in 2008 underwent a six month long outburst, starting (unusually) with an X-ray burst. We
detected a total of 57 thermonuclear bursts throughout the outburst with AGILE, Swift, RXTE,
and INTEGRAL. The wide range of inferred accretion rates (between <1% and 20% of the Eddington
accretion rate m˙ Edd) spanned during the outburst allows us to study changes in the nuclear
burning processes and to identify up to seven different phases. The burst rate increased gradually
with the accretion rate until it dropped (at a persistent flux corresponding to 15%of m˙ Edd) a few
days before the outburst peak, after which bursts were not detected for a month. As the persistent
emission subsequently decreased, the bursting activity resumed at a much lower rate than during
the outburst rise. This hysteresis may arise from the thermal effect of the accretion on the surface
nuclear burning processes, and the timescale is roughly consistent with that expected for the neutron
star crust thermal response. On the other hand, an undetected “superburst”, occurring within
a data gap near the outburst peak, could have produced a similar quenching of burst activity.
Original language | English |
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Title of host publication | Proceedings of Science : PoS (INTEGRAL 2010) |
Publication date | 2010 |
Publication status | Published - 2010 |
Event | INTEGRAL Workshop : The Restless Gamma-ray Universe - Dublin, Ireland Duration: 1 Jan 2010 → … Conference number: 8 |
Conference
Conference | INTEGRAL Workshop : The Restless Gamma-ray Universe |
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Number | 8 |
City | Dublin, Ireland |
Period | 01/01/2010 → … |