Report
The 2015 outburst of the accretion-powered pulsar IGR J00291+5934: INTEGRAL and Swift observations
| العنوان: | The 2015 outburst of the accretion-powered pulsar IGR J00291+5934: INTEGRAL and Swift observations |
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| المؤلفون: | De Falco, V., Kuiper, L., Bozzo, E., Galloway, D. K., Poutanen, J., Ferrigno, C., Stella, L., Falanga, M. |
| سنة النشر: | 2016 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - High Energy Astrophysical Phenomena |
| الوصف: | IGR J00291+5934 is the fastest-known accretion-powered X-ray pulsar, discovered during a transient outburst in 2004. In this paper, we report on Integral and Swift observations during the 2015 outburst, which lasts for $\sim25$ d. The source has not been observed in outburst since 2008, suggesting that the long-term accretion rate has decreased by a factor of two since discovery. The averaged broad-band (0.1 - 250 keV) persistent spectrum in 2015 is well described by a thermal Comptonization model with a column density of $N_{\rm H} \approx4\times10^{21}$ cm$^{-2}$, a plasma temperature of $kT_{\rm e} \approx50$ keV, and a Thomson optical depth of $\tau_{\rm T}\approx1$. Pulsations at the known spin period of the source are detected in the Integral data up to the $\sim150$ keV energy band. We also report on the discovery of the first thermonuclear burst observed from IGR J00291+5934, which lasts around 7 min and occurs at a persistent emission level corresponding to roughly $1.6\%$ of the Eddington accretion rate. The properties of the burst suggest it is powered primarily by helium ignited at a depth of $y_{\rm ign}\approx1.5\times10^9$ g cm$^{-2}$ following the exhaustion by steady burning of the accreted hydrogen. The Swift/BAT data from the first $\sim20$ s of the burst provide indications of a photospheric radius expansion phase. Assuming this is the case, we infer a source distance of $d = 4.2 \pm 0.3$ kpc. Comment: 8 Pages, 6 figures, 5 tables. Accepted for publication on 5 December 2016 by the Journal A&A |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1051/0004-6361/201629575 |
| URL الوصول: | http://arxiv.org/abs/1611.08218 |
| رقم الانضمام: | edsarx.1611.08218 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1051/0004-6361/201629575 |
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