Central Bureau for Astronomical Telegrams
IAUC 6083: KS 1730-312; X-RAY N 1993 IN Oph
The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).
Read IAUC 6084
.dvi or
.ps format.
Circular No. 6083
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)
KS 1730-312
K. Borozdin, N. Alexandrovich, V. Arefiev and R. Sunyaev, Space
Research Institute, Moscow, on behalf of the MIR-KVANT-TTM team,
communicate: "During observations of the Galactic Center field by the
TTM coded-mask instrument onboard the MIR space station on Sept. 23, a
flux of 70 +/- 10 mCrab within the energy band 2-30 keV was detected from
R.A. = 17h30m.3, Decl. = -31d11' (equinox 1950.0, uncertainty +/- 2').
The source spectrum can be approximated by a power law with spectral
index -1.9 +/- 0.4."
E. Churazov, M. Gilfanov, J. Ballet and E. Jourdain, on behalf of
the Granat Team (Space Research Institute, Moscow; Service d'Astrophysique,
Centre d'Etudes de Saclay; and Centre d'Etude Spatiale des Rayonnements,
Toulouse), report: "During observations of the Galactic Center region
on Sept. 22-23 the SIGMA telescope onboard Granat Observatory detected
a new hard x-ray source that is compatible with the above position.
The 40-150-keV flux from the source was about 130 mCrab. No significant
emission from this source has been detected by SIGMA in previous
observations, performed during Sept. 1-22 with 3-sigma upper limits of
40 mCrab (Sept. 20-22) and 15 mCrab (Sept. 1-22). In subsequent
observations on Sept. 24-25 and 25-26 the source flux was 116 and 93
mCrab, respectively. Gradual softening of the spectrum has been observed
with the power-law photon index changing from 2.2 +/- 0.2 on Sept. 22-23
to 2.9 +/- 0.5 on Sept. 25-26."
X-RAY NOVA 1993 IN OPHIUCHUS
Churazov et al. add: "In the course of the same set of Galactic
Center observations SIGMA detected hard x-ray emission from the x-ray
nova observed in Ophiuchus in 1993 (cf. IAUC 5874, 5876, et seq.;
R.A. = 17h16m.5, Decl. = -24d58', equinox 1950.0). The source was present
in the 40-150-keV band during the whole interval 1994 Sept. 1-23. The
time-averaged flux from the source is about 110 mCrab. A power-law
approximation to the source spectrum gives the photon index 2.3 +/- 0.3."
Borozdin and Alexandrovich report: "The TTM coded-mask instrument
onboard MIR registered x-ray emission from the direction of the 1993
x-ray nova with flux 55 +/- 15 mCrab (at 2-30 keV), averaged over
observations on 1994 Aug. 31, Sept. 1 and 23. The photon index of the
power-law approximation is 2.0 +/- 0.7."
1994 September 30 (6083) Brian G. Marsden
Read IAUC 6084
.dvi or
.ps format.
Our Web policy. Index to the CBAT/MPC/ICQ pages.
