Galactic black hole transient H1743-322 in transition to the hard state
ATel #1378; E. Kalemci (Sabanci Univ.), J. A. Tomsick (SSL / UC Berkeley), S. Corbel ((CEA Saclay & UniversitÃ© Paris Diderot) , T. Tzioumis (ATNF)
on 3 Feb 2008; 07:57 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Emrah Kalemci (email@example.com)
Subjects: Radio, Far-Infra-Red, Infra-Red, Optical, X-ray, Gamma Ray, Request for Observations, Binary, Black Hole, Transient
Galactic black hole transient H1743-322 has been in outburst since Jan 4, 2008
(ATEL #1348, #1349, #1352). We have analyzed the RXTE PCA data taken
on Jan 24 and Feb 1st. Quick fits to both data sets with a power law +
diskbb + smedge model were performed. On Jan 24, the photon index was 2.3. The
ratio of the power law flux to the overall flux in the 3-25 keV band was
70%. The power spectrum showed weak broad band noise with 8% rms
amplitude of variability. The source perhaps entered the hard
intermediate state at the time.
A radio observation with ATCA on January 28 resulted in no detection with an
rms upper limit of 0.15 mJy at 8.6 and 4.8 GHz.
On Feb 1st, the photon index was 1.55, and the power law flux was 90% of the overall
flux. The power spectrum showed a QPO at 4.5 Hz, and stronger broad band noise with
15% rms amplitude. Based on these results, the source is about to, or has already
transited to the hard state, and radio and OIR activity are expected, and
multi-wavelength observations are encouraged.