INTEGRAL Galactic Plane Scanning shows 4U 0115+63 appearing to enter a new type-II outburst
ATel #3434; S. P. Drave (Univ. of Southampton, UK), A. J. Bird (Univ. of Southampton, UK), M. Fiocchi (IASF-INAF, ROMA, Italy), V. Sguera (IASF-INAF, Bologna, Italy), L. Sidoli (IASF-INAF, Milano, Italy), E. Kuulkers (ESA/ESAC, Spain) on behalf of the INTEGRAL Galactic Plane Scanning team.
on 16 Jun 2011; 16:25 UT
Credential Certification: L. J. Townsend (ljt203@soton.ac.uk)
Subjects: X-ray, Gamma Ray, Request for Observations, Binary, Neutron Star, Transient, Pulsar
Observations from the on-going INTEGRAL Galactic Plane Scanning programme have detected increasing X-ray flux from the X-ray binary pulsar 4U 0115+63 that suggests the source is entering a new type-II X-ray outburst. The X-ray flux has increased over the last five days and is currently (2011-06-16 04:56:50 UTC) 230 mCrab in the 3-10 keV range and 100 mCrab in the 18-60 keV using the JEM-X and IBIS detectors respectively. These detections follow the initial brightening reported by MAXI/GSC (ATel #3430).
Archival IBIS data show a separation of ~3.5 years between the peaks of the previous two type-II X-ray outbursts, consistent with the 3 year quasi-periodicity suggested by Whitlock et al. (1989, ApJ, 338, 381). The last type-II outburst was ~3.2 yrs ago and the current brightening suggests the onset of another type-II outburst event.
We encourage follow-up observations in other wavebands to follow the evolution of this type-II outburst event from its onset. We will continue to monitor the outburst with INTEGRAL through the GPS program until the end of June 22. Light curves and images can be found on the GPS webpages here: http://gpsiasf.iasf-roma.inaf.it/
We would like to thank the staff at the ISDC for their assistance.