Circular No. 6567
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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COMET C/1995 O1 (HALE-BOPP)
     H. Matthews, Joint Astronomy Centre, Hilo, and Herzberg
Institute of Astrophysics; and D. Jewitt, University of Hawaii,
report on observations of several isotopes in the gas coma of
C/1995 O1 with the James Clerk Maxwell Telescope:  "Preliminary
measurements from Feb. 16 UT yield H12CN(4-3)/H13CN(4-3) = 90 +/-
10 and HC14N(4-3)/HC15N(4-3) = 299 +/- 30.  Both ratios include a
modest correction for the effects of optical depth in the HCN line.
We believe that this is the first determination of 14N/15N in a
comet.  In addition, on Feb. 23 we determined C32S(5-4)/C34S(5-4) =
27 +/- 3.  The CS line was optically thin.  Within the
uncertainties, these isotope ratios are compatible with the
terrestrial values 12C/13C = 89, 14N/15N = 270, and 32S/34S = 24.
The 362.0465-GHz transition of DCN(5-4) was also sought.  A 3-sigma
upper limit to the line ratio HCN(4-3)/DCN(5-4) = 300 was found on
Feb. 15, indicating that deuterium is not highly enriched in C/1995
O1 relative to the interstellar value."


GRB 970111
     F. Frontera, Universita di Ferrara; E. Costa and L. Piro,
Istituto Astrofisica Spaziale, Frascati; L. A. Antonelli, BeppoSAX,
Rome; W. Voges and T. Boller, Max-Planck-Institut fur
Extraterrestrische Physik, Garching; and J. Greiner,
Astrophysikalisches Institut Potsdam, communicate:  "A 1300-s ROSAT
HRI observation on Jan. 16 of the location of the GRB 970111 has
revealed three x-ray sources in the field-of-view; an image is
available at http://www.aip.de:8080/~jcg/grb970111.html.  Only one
of these three is inside the reduced error box (Hurley et al., IAUC
6545):  RX J152845+1944.5, at R.A. = 15h28m45s.0, Decl. = +19o44'31"
(equinox 2000.0, error radius 10").  This source coincides with the
BeppoSAX source 'a' (IAUC 6539), the radio source VLA J1528.7+1945
(IAUC 6545), and the two galaxies (IAUC 6559); its intensity of
0.0082 +/- 0.0025 count/s is consistent with that of the ROSAT all-
sky-survey (RASS) source 1 (IAUC 6539), implying no x-ray
variability between 1991 and 1997.  If RX J152845+1944.5 = BeppoSAX
'a' is related to one of the two galaxies S1 or S2 (IAUC 6559), its
x-ray luminosity is of the order of 5 x 10E44 erg/s in the range
0.1-2.4 keV, which is typical for an active galactic nucleus.  The
BeppoSAX source 'b', as well as the two RASS sources 2 and 3 (IAUC
6539), are not detected in the HRI observation, with marginal
evidence for an intensity drop by a factor of two for source 3
between 1991 and 1997." 

                      (C) Copyright 1997 CBAT                    
1997 February 24               (6567)            Daniel W. E. Green