Central Bureau for Astronomical Telegrams
IAUC 6604: GRS 1737-31; C/1995 O1
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 6605
.dvi or
.ps format.
Circular No. 6604
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/cfa/ps/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)
GRS 1737-31
W. Cui and E. H. Morgan, Massachusetts Institute of Technology;
W. A. Heindl, University of California, San Diego; J. H. Swank,
Goddard Space Flight Center; and D. M. Smith, University of
California, Berkeley, report: "Preliminary results of the RXTE
observation noted on IAUC 6603 reveal remarkable similarities to
the blackhole candidate Cyg X-1 in its hard (or low) state. The
power-density spectrum is flat below about 0.03 Hz and roughly
inversely proportional to the frequency above, with an integrated
rms variability of 21.4 percent. The energy spectrum can be
characterized by a power law with photon index about 1.6. A more
detailed analysis is required to determine if an iron line at about
6.4 keV is accounted for by the diffuse x-ray emission in the
central region of the galactic plane. The best-fit hydrogen column
density is 4-6 x 10E22 cm**2, depending on the diffuse background,
in any case consistent with a location near the galactic center.
Fluxes in the bands 2-10, 10-35, 35-75, and 75-150 keV were 18, 37,
60, and 90 mCrab, respectively. Assuming a distance of 8.5 kpc,
the 2-150-keV source luminosity was 1.9 x 10E37 erg/s.
Similarities to Cyg X-1 make GRS 1737-31 a likely black hole
candidate. Further observations at all wavelengths, in particular,
infrared and radio, are encouraged."
COMET C/1995 O1 (HALE-BOPP)
N. Dello Russo, M. A. DiSanti, and M. J. Mumma, Goddard Space
Flight Center, NASA; K. Magee-Sauer, Rowan College of New Jersey;
R. Novak, Iona College; and M. Fomenkova, University of California
at San Diego, report: "We detected water in C/1995 O1 on Jan. 21.5,
Feb. 23.9-24.1, and Mar. 1.7-1.9 UT, using the NASA Infrared
Telescope Facility (+ CSHELL cryogenic infrared spectrometer) on
Mauna Kea. For Feb. 23.9, line fluxes (x 10E-17 W mE-2, in an
aperture 1" x 1".4 centered on the nucleus) were as follows: 111-
100 band and 202-303 line, 1.2; 100-010 band and 101-110 line, 7.2.
Five lines were analyzed. Lines of the 001-010 vibrational band
were also detected but show the expected effect of an optically-
thick pump and so were not used in these reductions. The water-
production rate (x 10E30 molecules/s) was 2.7 on Jan. 21.5, 4.3 on
Feb. 23.9, and 4.0 on Mar. 1.8, assuming a rotational temperature
of 70 K and an ortho-para-ratio of 2.45. After detailed data
reduction, we report that spectral lines of HDO (100 vibrational
band) were not detected, contrary to the report on IAUC 6573. The
preliminary reductions were adversely affected by high and variable
telluric HDO."
(C) Copyright 1997 CBAT
1997 March 26 (6604) Daniel W. E. Green
Read IAUC 6605
.dvi or
.ps format.
Our Web policy. Index to the CBAT/MPC/ICQ pages.
