Renewed hard X-ray activity of SAX J2103.5+4545 detected by INTEGRAL
ATel #12812; L. Ducci (IAAT, Germany; ISDC, Switzerland), L. Sidoli (INAF-IASF Milano, Italy), J. Wilms (ECAP, Germany), V. Grinberg (IAAT, Germany), C. Sanchez (ESA/ESAC, Spain), J. Rodriguez (CEA Saclay/lab AIM, France), C. Ferrigno, E. Bozzo, V. Savchenko (ISDC, Switzerland)
on 28 May 2019; 16:41 UT
Credential Certification: Lorenzo Ducci (lorenzo.ducci@unige.ch)
Subjects: X-ray, Binary, Neutron Star, Transient
We report on the recent detection of renewed activity
from the transient Be/X-ray binary system SAX J2103.5+4545
obtained with IBIS/ISGRI on board INTEGRAL.
The observations were performed in the direction of Cyg X-1,
during the INTEGRAL revolution 2094,
from 2019 May 23 at 19:02 (UTC) to 2019 May 25 at 23:09 (UTC),
and during revolution 2095, from 2019 May 23 at 10:17 (UTC) to
2019 May 28 at 13:03 (UTC).
During revolution 2094, SAX J2103.5+4545 is detected in the IBIS/ISGRI
mosaic at a significance level of 18 (8) and a flux of 48 ± 3 mCrab (34 ± 4 mCrab)
in the 20-40 keV (40-80 keV) energy band (uncertainties are given at
68% confidence level).
The average IBIS/ISGRI spectrum (30-100 keV; effective exposure time 45 ks)
obtained combining the available near real time (NRT) INTEGRAL observations
of revolution 2094, could be well described (χ2red/dof=0.792/17) with a cutoff power-law
with photon index 0.3 ± 1 and cutoff energy 18 ± 9 keV.
During revolution 2095, SAX J2103.5+4545 is detected
in the 20-40 keV mosaic, with a flux of 28 ± 3 mCrab.
The source is outside the JEM-X (3-30 keV) field of view.
A more complete analysis will be carried on the consolidated INTEGRAL data.
The brightening of SAX J2103.5+4545 is also observed by the Swift/BAT monitoring (https://swift.gsfc.nasa.gov/results/transients/weak/SAXJ2103.5p4545/).
Further INTEGRAL observations in the direction of SAX J2103.5+4545
are planned in the next days.
Observations in soft X-rays, as well as in other energy domains, are encouraged.
