Issue |
A&A
Volume 510, February 2010
|
|
---|---|---|
Article Number | A81 | |
Number of page(s) | 8 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361/200912647 | |
Published online | 16 February 2010 |
Type-I bursts within outbursts of IGR J17473-2721
1
Laboratory for Particle Astrophysics, Institute of High
Energy Physics, Beijing 100049, PR China e-mail: chenyp@mail.ihep.ac.cn
2
ICREA & Institut de Ciències de l'Espai (IEEC-CSIC), Campus UAB,
Facultat de Ciències, Torre C5-parell, 2a planta, 08193 Barcelona,
Spain
3
Theoretical Physics Center for Science Facilities (TPCSF), CAS
4
Center for Astrophysics, Tsinghua University, Beijing 100084, PR China
Received:
6
June
2009
Accepted:
31
October
2009
Aims. Two outbursts were observed by RXTE in the history of the atoll source IGR J17473-2721. During the most recent outburst in 2008, the source showed a complete series of spectral states/transitions. The neutron star system was prolific in type-I X-ray bursts, and we investigate them in the context of complete outbursts evolution.
Methods. A total exposure of ~309 ks was collected by RXTE during the two outbursts of IGR J17473-2721. We carried out a systematic search for type-I bursts in this data set. For each burst found, we investigated the burst profile, the peak flux, and their dependence on the accretion rate along the evolution of the outbursts.
Results. Eighteen type-I X-ray bursts were found from IGR J17473-2721: two from the outburst in 2005 and the other 16 from the recent outburst in 2008. Among them, 3 bursts show photospheric radius expansion (PRE). The distance to the source is estimated as 6.4 kpc with a 15% uncertainty based on the three bursts that show PRE. In the recent outburst, there are 6 bursts showing up in the low/hard state prior to the state transition to a high/soft state, 3 bursts at the end phase of the high/soft state, and 7 in the following low/hard state. The blackbody radius of these bursts presents a variety of interesting features. We find that, at the end of the recent outburst, the profile of the blackbody radius is anti-correlated with the blackbody temperature and the burst flux. The durations of the type-I burst are found to correlate with the Eddington ratio and to have two parallel evolution groups. Along the decreasing Eddington ratio, the burst duration decreases and ends in each group the PRE bursts occurred. This provides new clues to the type-I bursts in the context of outbursts for atoll XRBs.
Key words: star: neutron / individual: IGR J17473-2721 / X-rays: bursts
© ESO, 2010
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.