Hard X-ray emission from the HMXB 4U2238+60 (SAX J2239.3+6116) detected with INTEGRAL
ATel #16800; Mariateresa Fiocchi (IAPS/INAF) on behalf of the IBIS/GPS Team
on 4 Sep 2024; 13:14 UT
Credential Certification: mariateresa fiocchi (mariateresa.fiocchi@inaf.it)
Subjects: X-ray, Binary, Transient
Referred to by ATel #: 16803
A new outburst from the high-mass X-ray binary 4U 2238+60 was recently observed by Einstein Probe (ATel #16750) WXT on 2024-08-01 (MJD 60523) and FXT on 2024-08-03 (MJD 60525)
The ongoing outburst is consistent with the outburst periodicity of 262.6±0.7 d claimed by in t' Zand et al. 2001 and confirmed by MAXI/GSC historical data (ATel #16762).
4U 2238+60 was detected during INTEGRAL Galactic Plane Scan observations (PI: Angela Bazzano) on revolutions 2809 (start MJD 60530.319), 2810 (start MJD 60531.335) and 2813 (start MJD 60539.315). This transient source was detected in the 28-60 keV energy band by the IBIS/ISGRI instrument at significances of 18-sigma, 23-sigma, and 11-sigma, respectively.
The X-ray source is also well detected by the combined JEM-X1+2 instruments at 25 sigma for a total effective exposure of 34.5 ks. The average flux measured from near-real-time data is 16 +/-1 mCrab between 3-25 keV.
The X-ray spectra of the source are well fitted with a power-law model. The parameters derived from these fits are as follows:
| Revolution |
Exposure |
Gamma |
Flux (28-60 keV) |
Reduced chi-squared |
|
ks |
|
10-10 erg cm-2 s-1 |
|
| 2809 |
32.6 |
3.5+/-0.3 |
1.11+/-0.06 |
1.1 |
| 2810 |
30.0 |
4.1+/-0.4 |
1.82+/-0.08 |
1.4 |
| 2813 |
30.0 |
3.3+/-0.5 |
0.81+/-0.07 |
0.8 |
All the data have been analyzed using the Offline Software Analysis version 11.2 (OSA11).
Further observations at other wavelengths are encouraged.
Results from the Galactic Plane Scanning are made publicly available at:
http://gps.iaps.inaf.it
