INTEGRAL observation of renewed activity from 4U 1608-522
ATel #2464; W. Ishibashi and C. Ferrigno (ISDC/University of Geneva), C. SÃ¡nchez-FernÃ¡ndez and E. Kuulkers (ESAC-ESA, Spain), J. Chenevez (National Space Institute, Denmark)
on 5 Mar 2010; 17:40 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Nami Mowlavi (Nami.Mowlavi@obs.unige.ch)
Subjects: X-ray, Gamma Ray, Binary
Referred to by ATel #: 2467
On 3 March 2010 SuperAGILE detected an X-ray burst from the LMXB 4U 1608-522 (Atel #2461).
Confirmation of the renewed activity of this transient source was reported by MAXI/GSC (Atel #2462).
4U1608-522 was in the IBIS/ISGRI and JEMX field of view during several
observations between 2010-Feb-23 06:20 and 2010-March-03 01:04 UTC,
when INTEGRAL was monitoring the inner Galactic Disk.
The source was detected by JEMX since March 2, with a flux of 17+/-2
mCrab in the 3-20 keV band. Before that time the source was not
detectable by JEMX. We derive an upper limit of about 10 mCrab in the
3-20 keV band between Feb. 23 and March, 2. We suggest the onset
of the outburst to happen at March 1. This in agreement with the
results derived by MAXI/GSC (Atel #2462). No X-ray bursts were detected
within the INTEGRAL observations.
The JEMX spectrum, accumulated between 2010-Mar-02 19:12 and 2010-Mar-03 0:57 UTC
for a total exposure time of 8.8 ks,
can be fit by using an absorbed power-law
model. We fixed the absorption column density at 1.2E22 cmÂ² and
obtained a power-law photon index of 2.8+/-0.4. The estimated source
flux in the 3-10 keV energy band is 3.3E-10 ergs/cmÂ²/s.
During the whole observation time, the source was not detected by IBIS/ISGRI.
We derive an upper limit (5-sigma) on the X-ray flux of 5-10 mCrab in the 20-40 keV band.
INTEGRAL is currently observing the field of GX 339-4 (March 4th-6th)
and will continue monitoring of the inner Galactic Disk until the end of March.
4U 1608-522 will be visible during these observations
We acknowledge support from the ISDC operation team for this analysis.