INTEGRAL detection of the X-ray transient Swift J1858.6-0814
ATel #12167; E. Bozzo, C. Ferrigno, V. Savchenko (ISDC, Switzerland), L. Ducci (IAAT, Germany; ISDC, Switzerland), E. Kuulkers (ESA/ESTEC, Netherlands)
on 4 Nov 2018; 14:06 UT
Credential Certification: E. Bozzo (enrico.bozzo@unige.ch)
Subjects: X-ray, Transient
The recently discovered X-ray transient Swift J1858.6-0814 (ATel #12151, #12158, #12160, #12163, #12164) has been observed by INTEGRAL during some slewing science windows (SCWs) performed in revolution 2013 (SCWs 99 and 100), 2014 (SCWs 96 and 97), 2015 (SCWs 93 and 94), 2016 (SCWs 93 and 94), and 2017 (SCWs 92 and 93). These SCWs cover the period from 2018 October 22 at 15:04 to November 2 at 6:55 UT.
We built the IBIS/ISGRI mosaic combining all the above mentioned SCWs and found that the source is detected at a significance of 9 sigma in the 20-40 keV energy band and the corresponding flux is 28+/-3 mCrab. The source is only marginally detected in the 40-80 keV energy band (5 sigma) with an estimated flux of 25+/-5 mCrab.
The IBIS/ISGRI spectrum (effective exposure time 3.5 ks) could be preliminary described (reduced chi^2/d.o.f. = 1.3/8) with a power-law model. We measured a photon index of 2.2+/-0.7 and a 20-100 keV flux of 3.6E-10 erg/cm^2/s.
No JEM-X data are available for the considered SCWs.
No pointed observations with INTEGRAL have been already planned for Swift J1858.6-0814, but it will be serendipitously observed during similar slewing SCWs in the coming days.
