Central Bureau for Astronomical Telegrams
IAUC 4764: 1987A; NSV 01098
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Circular No. 4764
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 or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
SUPERNOVA 1987A IN THE LARGE MAGELLANIC CLOUD
The GRIS collaboration (S. Barthelmy and N. Gehrels, Goddard
Space Flight Center; M. Leventhal, ATT/Bell Laboratories; C. J.
MacCallum, Sandia National Laboratory; and B. J. Teegarden and J.
Tueller, GSFC) communicates: "We report detection of gamma-ray
lines from SN 1987A. The GRIS payload is an array of high-resolution,
cooled germanium detectors for gamma-ray spectroscopy. The payload
was launched on a high-altitude balloon from Alice Springs, Australia,
on the evening of 1988 Oct. 28 (day 613). Two transits of SN 1987A
were obtained for a total of 16 hr on-source. Both the 847- and
1238-keV lines from the decay of 56Co were observed, at the 4.6-sigma
and 3.4-sigma significance levels, respectively. A least-squares fit
to a gaussian line profile has been performed on both lines. The
fluxes determined from these fits are (6.5 +/- 1.4) x 10E-4
photons/cm2/s for the 847-keV line and (3.1 +/- 0.9) x 10E-4
photons/cm2/s for the 1238-keV line. These fluxes are in reasonable
agreement with theoretical models like the 10HMM model of Pinto and
Woosley (1988, Nature 333, 534, and private communication). The peak
energy determined from the fit for the 847-keV line is 844.2 +/- 1.3
keV and the FWHM is 10.8 +2.9/-2.4 keV. For the 1238-keV line, the
peak energy is 1233.5 +/- 1.8 keV and the FWHM is 11.0 +3.7/-3.1 keV.
Both line profiles are consistent with a single velocity distribution
at the source (mean velocity corrected for LMC redshift is -770 +/-
320 km/s and FWHM is 3200 +680/-570 km/s), but peak energies are not
consistent (> 3 sigma for each line) with the 10HMM model or other
spherically symmetric mixed models, which all predict blueshifted
lines. The line widths are consistently about a factor of two larger
than predicted (1.5-sigma to 2-sigma significance for each line).
These results are consistent with the line profile observed in the
previous GRIS flight on day 433 (IAUC 4593)."
NSV 01098
Visual magnitude estimates (cf. IAUC 4722): Jan. 26.84 UT, 9.8
(A. Boattini, Florence, Italy); Feb. 8.88, 9.8 (R. Monella, Covo,
Italy); 17.09, 9.6 (P. Schmeer, Bischmisheim, West Germany); 26.87,
9.6 (A. Pereira, Cabo da Roca, Portugal); Mar. 4.86, 9.7 (Monella);
11.83, 10.1 (Pereira); 19.07, 10.1 (Schmeer); 24.81, 10.7 (Boattini).
1989 March 30 (4764) Daniel W. E. Green
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