Volume 508, Number 2, December III 2009
|Page(s)||889 - 894|
|Section||Stellar structure and evolution|
|Published online||15 October 2009|
The nature of the X-ray binary IGR J19294+1816 from INTEGRAL, RXTE, and Swift observations
Laboratoire AIM, CEA/DSM – CNRS – Université Paris Diderot (UMR 7158), CEA Saclay, DSM/IRFU/SAp, 91191 Gif-sur-Yvette, France e-mail: email@example.com
2 Space Science Laboratory, 7 Gauss Way, University of California, Berkeley, C1 94720-7450, USA
3 INAF-IASF, Sezione di Milano, via Bassini 15, 20133 Milano, Italy
Accepted: 9 October 2009
We report the results of a high-energy multi-instrumental campaign with INTEGRAL, RXTE, and Swift of the recently discovered INTEGRAL source IGR J19294+1816. The Swift/XRT data allow us to refine the position of the source to = = +18° 18′38.4″ (±3.5″), which in turn permits us to identify a candidate infrared counterpart. The Swift and RXTE spectra are well fitted with absorbed power laws with hard (Γ ~ 1) photon indices. During the longest Swift observation, we obtained evidence of absorption in true excess to the Galactic value, which may indicate some intrinsic absorption in this source. We detected a strong (%) pulsation at 12.43781 (±0.00003) s that we interpret as the spin period of a pulsar. All these results, coupled with the possible 117 day orbital period, point to IGR J19294+1816 being an HMXB with a Be companion star. However, while the long-term INTEGRAL/IBIS/ISGRI 18-40 keV light curve shows that the source spends most of its time in an undetectable state, we detect occurrences of short (~ s) and intense flares that are more typical of supergiant fast X-ray transients. We therefore cannot make firm conclusions on the type of system, and we discuss the possible implications of IGR J19294+1816 being an SFXT.
Key words: X-rays: binaries / accretion, accretion disks / stars: individual: IGR J19294+1816 / stars: individual: IGR J11215-5952 / stars: individual: IGR J18483-0311
© ESO, 2009
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.