Volume 536, December 2011
|Number of page(s)||4|
|Published online||09 December 2011|
Letter to the Editor
Quasi-periodic flares in EXO 2030+375 observed with INTEGRAL
Institut für Astronomie und Astrophysik, Universität Tübingen (IAAT), Sand 1, 72076 Tübingen, Germany
2 ISDC Data Center for Astrophysics of the University of Geneva, chemin d’Écogia 16, 1290 Versoix, Switzerland
3 European Space Astronomy Centre (ESA/ESAC), Science Operations Department, Villanueva de la Canãda ( Madrid), Spain
4 CEA Saclay, DSM/IRFU/SAp-UMR AIM (7158) CNRS/CEA/Université Paris Diderot, 91191 Gif-sur-Yvette, France
5 Sternberg Astronomical Institute, Universitetski pr. 13, 119991 Moscow, Russia
6 NASA Marshall Space Flight Center, Huntsville, AL 35812, USA
Received: 30 September 2011
Accepted: 6 November 2011
Context. Episodic flaring activity is a common feature of X-ray pulsars in HMXBs. In some Be/X-ray binaries flares were observed in quiescence or prior to outbursts. EXO 2030+375 is a Be/X-ray binary showing “normal” outbursts almost every ~46 days, near periastron passage of the orbital revolution. Some of these outbursts were occasionally monitored with the INTEGRAL observatory.
Aims. The INTEGRAL data revealed strong quasi-periodic flaring activity during the rising part of one of the system’s outburst. Such activity has previously been observed in EXO 2030+375 only once, in 1985 with EXOSAT. (Some indications of single flares have also been observed with other satellites.)
Methods. We present the analysis of the flaring behavior of the source based on INTEGRAL data and compare it with the flares observed in EXO 2030+375 in 1985.
Results. Based on the observational properties of the flares, we argue that the instability at the inner edge of the accretion disk is the most probable cause of the flaring activity.
Key words: stars: neutron / accretion, accretion disks / X-rays: binaries
© ESO, 2011
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.