[ Previous | Next ]
ATEL # 2530; Manousakis A., Ferrigno C. (ISDC-University of Geneva), Weidenspointner G. (MPE), Kuulkers E. (ESA/ESAC) Bozzo E. (ISDC-University of Geneva), Mereghetti S. (IASF-Mi/INAF), Gotz D. (CEA), Fiocchi M. (IASF-Rm/INAF), Watanabe K. (FGCU) Rothschild R. (UCSD), Kuiper L.M. (SRON), Chenevez J. (DTU Space), Caballero I. (CEA), Ducci L. (IASF-Mi/INAF) Bird A.J. (Southampton, UK), Puehlhofer G. (IAA Tuebingen), Sanchez C. (ESA/ESAC), Del Santo M (IASF-Rm/INAF) Negueruela I. (Alicante), Bianchin V. (IASF-Bo/INAF), Prat L. (CEA), Paizis A. (IASF-Mi/INAF), Tarana A. (IASF-Rm/INAF), Panessa F. (IASF-Rm/INAF), Fiamma C. (IASF-Rm/INAF), Kreykenbohm I. (Dr. Karl Remeis Sternwarte Bamberg)) Terrier R. (APC)
on 1 Apr 2010; 11:34 UT
Distributed as an Instant Email Notice (Transients)
Password Certification: Nami Mowlavi (Nami.Mowlavi@obs.unige.ch)
Subjects: Binaries, Black Holes, Transients
The latest RXTE observations of XTEJ1752-223 detected this source
in an intermediate state, and suggested that a spectral transition
from the soft to the hard state was most likely taking place
Following this announcement, we analyzed the INTEGRAL data
of the latest revolutions in the direction of the source.
In the period preceding the suspected spectral change,
XTEJ1752-223 was inside the IBIS/ISGRI field of view
from 2010-03-25 13:17 to 2010-03-27 02:08 (UTC).
The source was detected at 6 sigma level in the 20-40 keV ISGRI mosaic
(effective exposure time 21 ks), and the corresponding X-ray flux was
of 7E-11 erg/cm^2/s. The ISGRI spectrum could be only poorly characterized
and was compatible with a power-law of photon index 3+/-1.
XTEJ1752-223 was again in the FOV of ISGRI after the announced
spectral transition from 2010-03-27 at 10:03 to 2010-03-30 at 02:08 (UTC).
The source was detected at 21 sigma in the 20-40 keV ISGRI mosaic, and
the corresponding X-ray flux was 2.8E-10 erg/cm^2/s (effective exposure time 36 ks).
The ISGRI spectrum could be described by a power law with a
photon index of 2.8+/-0.3 above 23 keV.
Further observations of the source took place from 2010-03-30 09:52
to 2010-03-30 13:33 (UTC). The source was detected at 15 sigma in
the 20-40 keV ISGRI mosaic (effective exposure time 7.3 ks), and the
corresponding X-ray flux was 3.2E-10 erg/cm^2/s.
The ISGRI spectrum above 25 keV could be roughly modeled
with a power-law of photon index 1.7+/-0.5.
The measured change in the spectral photon index of
XTEJ1752-223 supports the idea that this source is
presently undergoing a spectral state transition.
XTEJ1752-223 was outside the JEMX2 FOV for the
entire observational period.