Faculty of Science (FNWI) - Anton Pannekoek Institute for Astronomy (API)
Abstract
The recently reported outburst from the supergiant fast X-ray transient XTE J1739-302/IGR J17391-3021 (ATEL #1466) began already about five hours earlier than the Swift/BAT trigger on 2008-04-08. The INTEGRAL/JEM-X monitor detected a flare starting at 16:18 (UTC) on the same day during recent Galactic Bulge monitoring observations (see ATEL #1385 and #1468). The flux averaged over the ~2 hour flare reached 42+/-8 mCrab (3-10 keV) and 80+/-15 mCrab (10-25 keV) with upper limits previous to the flare of 4 mCrab (3-10) keV and 8 mCrab (10-25 keV).