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IAUC 6599: C/1995 O1; GRS 1737-31

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                                                  Circular No. 6599
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)
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COMET C/1995 O1 (HALE-BOPP)
     J. E. Wink, Institut de Radio Astronomie Millimetrique (IRAM),
Grenoble; D. Bockelee-Morvan, N. Biver, P. Colom, J. Crovisier, E. Gerard
and H. Rauer, Observatoire de Paris; D. Despois, Observatoire de Bordeaux;
R. Moreno and G. Paubert, IRAM, Granada; and J. K. Davies and W. R. F.
Dent, Joint Astronomy Centre, Hilo, report the detection of formic acid
at the IRAM Plateau de Bure interferometer using its five antennae in a
single-dish mode: "On Mar. 20.6 UT the HCOOH rotational transitions at
224.977 GHz, 10(5,6)-9(5,5) and 10(5,5)-9(5,4), were detected with a
total integrated line area on a TA* scale of 0.08 +/- 0.01 K km/s.
The HCOOH lines at 224.929 and 225.238 GHz were also detected.
Assuming thermal excitation at 80 K, the derived HCOOH production rate
is about 5 x 10**27 molecules/s, which is 50 times smaller than that
of the related species CH3OH."

    A. J. Apponi, T. C. Pesch and L. M. Ziurys, Steward Observatory,
University of Arizona; and P. Wehinger and S. Wyckoff, Arizona State
University, report the first detection of methyl cyanide in
this comet: "On Mar. 20 the K = 0, 1, 2, 3 and 6 components
of the J=8-7 transition of CH3CN near 147.1 GHz were observed
using the NRAO 12-m telescope, with main beam brightness temperatures
of 0.083, 0.059, 0.060, 0.081 and 0.053 K, respectively.  Integrated
intensities for the two strongest K components, K = 0 and K = 3, were 0.18
and 0.13 K km/s.  In a search for vinyl cyanide (H2CCHCN) at 151.9 GHz
and ethyl cyanide (H3CCH2CN) at 152.3 GHz, no emission was detected to
limits of 0.03 K peak-to-peak of main beam brightness temperature."


GRS 1737-31
     R. Sunyaev, E. Churazov, M. Revnivtsev and S. Trudolyubov, Space
Research Institute, Moscow, and Max Planck Institute for Astrophysics,
Garching, report for M. Vargas, J. Paul, J.-P. Roques, E. Jourdain and
the GRANAT/SIGMA Team: "Since Mar. 14 GRANAT has been observing the
Galactic Center region.  Preliminary analysis of SIGMA hard x-ray images
revealed a new source in Scorpius at R.A. = 17h36m.7, Decl. = -30d57'
(equinox 1950.0, error +/- 3 arcmin), 2.4 deg from the Galactic Center,
at flux levels of 90 +/- 16 and 130 +/- 20 mCrab in the 35-75-keV and
75-150-keV bands, respectively.  The photon index of the spectrum in
this energy range is 1.6 +/- 0.3.  Assuming a distance of 8.5 kpc for
the source, the hard x-ray luminosity is about 10**37 erg/s.  The source
was detected at practically the same flux level on Mar. 14.23-15.59,
18.68-19.65 and 19.79-20.69 UT.  The spectrum hardness suggests that
this source is a distant x-ray nova and black-hole candidate."

                      (C) Copyright 1997 CBAT
1997 March 21                  (6599)              Brian G. Marsden

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