INTEGRAL has recently performed public observations of the Musca and Norma regions during Galactic Plane Scanning program (PI: A. Bazzano). During revolution 2048 (starting from 21 Jan 13:31 UTC), IBIS/ISGRI detected sources H1417-624 and GX 339-4 amongst others.
Renewed activity from the HMXB H1417-624 was detected with IBIS/ISGRI with an overall detection significance in the 22-60 keV band of 18.2 sigma. The flux was measured in the 22-60 keV band as 1.0 +/- 0.07-10 erg cm-2 s-1 (9.4 +/- 0.7 mCrab) with an effective exposure time of 15 ks. H1417-624 was detected by JEM-X, the flux values are as follows: 3-10 keV: 1.2 +/- 0.2-10 erg cm-2 s-1 (8 +/-1 mCrab); 10-25 keV: 0.3 +/- 0.2-10 erg cm-2 s-1 (8 +/-2 mCrab). H1417-624 is a Be X-ray Transient (Apparao et al. 1980, A&A 89, 249; Grindlay et al. 1984, ApJ 276, 621) showing a neutron star spin period of 17.54 s and an orbital period of 42.12 days (Finger et al. 1996, A&A Supp. Ser. 120, 209).
The black hole X-ray transient GX 339-4 was detected with IBIS/ISGRI with an overall detection significance in the 22-60 keV band of 11.92 sigma. The flux was measured in the 22-60 keV band as 7.7 +/- 0.6-10 erg cm-2 s-1 (71.7 +/- 6.0 mCrab) with an effective exposure time of 0.3 ks. A spectrum in the 30-110 keV range was obtained that is well modelled by an unabsorbed power-law model with a photon index of 2.24 +/- 0.3. GX 339-4 began its recent outburst in November 2018. The outburst was first observed by MeerKAT (ATel #12287), later confirmed by NuSTAR (ATel #12322) and most recently seen by Swift (ATel #12413). GX 339-4 was not in the JEM-X FOV during this revolution.
All the data have been analysed using the Offline Software Analysis version 11.0 (OSA11).
Further INTEGRAL Galactic Plane Scanning observations are planned in the coming days.
Results from the Galactic Plane Scanning are made publicly available at: http://gps.iaps.inaf.it
|Publication date||25 Jan 2019|
|Publication status||Published - 25 Jan 2019|
|Series||The Astronomer's telegram|