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IAUC 4535: 1988B; 1987A

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IAUC number

                                                  Circular No. 4535
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM    Telephone 617-495-7244/7440/7444

     A. V. Filippenko, University of California, Berkeley, provides
the following report, confirming that the object reported on IAUC
4533 and 4534 is a supernova:  "R. D. Cohen and V. T. Junkkarinen,
University of California at San Diego, used a Cassegrain CCD
spectrograph on the Shane 3-m reflector at Lick Observatory to obtain a
spectrum (range 430-710 nm, resolution 1.5-2 nm) of the SN candidate
in NGC 3191 on Jan. 23.  A verbal description of the spectrum
suggests that the object is a type-Ia SN.  There is no broad H-alpha
emission.  Broad absorption and emission features are visible at
approximate rest wavelengths of 613 nm and 460 nm, respectively."

     A. C. Rester, G. Eichhorn, and R. L. Coldwell, University of
Florida; J. I. Trombka, Goddard Space Flight Center; R. Starr,
Catholic University of America; and G. P. Lasche, DARPA/NMO, telex:
"The Gamma-Ray Advanced Detector (GRAD) Antarctic Supernova Observer
was successfully launched from Williams Field near McMurdo Station,
Antarctica, on Jan. 8.01 UT.  The balloon achieved a float altitude
of 36 km and drifted westward along -78 deg latitude with a speed of about
7 m/s.  After 3 days at float altitude, there were power supply
failures, so the flight was terminated and the payload recovered
360 km west of Vostok.  We achieved about 12 hr of observation in the
direction of SN 1987A (detecting both continuous and discrete line
gamma-ray spectral features) and about 9 hr in a direction away from the
supernova.  Preliminary analysis of the 847-keV and 1238-keV regions
shows broad line structure with possible line splitting.  The
shape in the 847-keV region is somewhat obscured by the 844-keV Al
background line.  The structure in the 1238-keV region extends from
about 1216 keV to about 1244 keV; if this feature is associated with the
56Co decay in the supernova, our results would indicate an expansion
velocity of about 1300 +/- 300 km/s and a recessional velocity
significantly > 270 km/s.  Tentative estimates of the fluxes in these
two regions are both about 0.0025 +/- 0.0013 photons/cm2/s.  Verification
of these preliminary results awaits more detailed analysis."
     Visual magnitude estimates by A. C. Beresford, Adelaide, South
Australia:  Jan. 20.54 UT, 6.3; 21.48, 6.4; 22.48, 6.3.

1988 January 25                (4535)            Daniel W. E. Green

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