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Swift follow-up of the new integral source IGRJ16442-554

ATEL # 2188; E. Bozzo (ISDC), C. Ferrigno (ISDC/IAAT), A. Manousakis (ISDC), M. Del Santo (INAF/IASF-Roma)
on 3 Sep 2009; 15:41 UT
Distributed as an Instant Email Notice (Transients)
Password Certification: Nami Mowlavi (

Subjects: X-ray, Gamma Ray, Transients

After the discovery of the new INTEGRAL source IGRJ16442-554 (Atel #2185), a Swift follow-up was requested. Swift/XRT observed IGRJ16442-554 on 2009-09-02 at 14:09:58 UT, for a total exposure time of 5 ks. Only one source was detected within the INTEGRAL/ISGRI error box.

The refined source position is:
RA: 16 44 38.15 DEC: -55 50 45.93 (J2000)
with an estimated error of 4.1 arcsec (90% c.l.).

The source count rate was relatively low, 2.7E-02 +/- 3.0E-3 cts/sec, and only a rough characterization of the spectrum could be obtained (we used the C-statistics). The Swift/XRT spectrum could be fit either by a power-law (photon index 1.9 +/- 0.9) or with a simple blackbody (kT=0.5 +/- 0.1 keV). In both cases the absorption column density turned out to be consistent with zero. The 0.5-10 keV flux was 1.1E-12 ergs/cm2/s, i.e. a factor ~50 lower than the flux determined by ISGRI in the 20-100 keV energy band. No significant variability was observed in the Swift/XRT light curve.

Inside the Swift/XRT error box we found one 2MASS source, 2MASS 16443770-5550454 (J=10.953+/-0.033, H=10.341+/-0.031, K=10.175+/-0.027), and one USNO B1 source, USNOB1 0341-0647474 (B2=12.95 R2=11.78, I=11.00). The positions of these two sources are coincident within ~1 arcsec.

Further analysis are ongoing. We encourage multi-wavelength observations.

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R. E. Rutledge , Editor
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