Central Bureau for Astronomical Telegrams
IAUC 4526: 1987A; CY UMa; N Vul 1987
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Circular No. 4526
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
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
SUPERNOVA 1987A IN THE LARGE MAGELLANIC CLOUD
W. Sandie, G. Nakano and L. Chase, Lockheed Palo Alto Research
Laboratory; G. Fishman, C. Meegan, R. Wilson and W. Paciesas, NASA
Marshall Space Flight Center; and G. Lasche, DARPA, report: "A
balloon-borne gamma-ray spectrometer (cf. IAUC 4463) was again flown from
Alice Springs, Australia, on 1987 Oct. 29-30-31. High-resolution
data, typically 2.5-keV FWHM at 1.33 MeV, from two transits of SN
1987A were obtained along with interspersed background observations.
A significant net flux of gamma-rays was observed on each transit
at 847 keV from the direction of SN 1987A. No prominent features
were seen at other energies. A preliminary estimate of the
line flux is approximately 5 x 10**-4 photons cm-2 s-1 with statistical
significance greater than 3 sigma. The line may be interpreted
as emission from the first excited state of 56Fe due to 56Co decay.
No emission is seen at the energy of the second excited state,
1238 keV. The 3-sigma upper limit for this line is about 5 x 10**-4 photons
cm-2 s-1. The flux level estimates will be refined as the instrument
systematics are better understood. Two large-area scintillation
detectors were also flown as part of the balloon-borne payload.
These detectors operated over the energy range 20-700 keV,
although they were most sensitive to SN 1987A in the range 50-200
keV. The following preliminary fluxes (in units of 10**-5 photons
cm-2 s-1 keV-1) were observed from the direction of SN 1987A: 50-
100 keV, flux 6.4 +/- 0.5; 100-200 keV, 2.9 +/- 0.2. The quoted errors
are statistical only; known systematic errors in the data could
change the absolute flux values by considerably more."
Visual magnitudes by A. C. Beresford, Adelaide, SA: Jan. 5.51
UT, 6.4; 6.47, 6.3; 7.49, 6.4; 8.47, 6.3; 9.50, 6.3; 11.45, 6.3.
CY URSAE MAJORIS
M. Watanabe, Toyama Science Center, reports via A. Izumo,
Yokohama Science Center, that T. Kato, Kyoto, has observed a rare
outburst of the U Gem-star CY UMa (R.A. = 10h54m02s, Decl. = +49 57'.2,
equinox 1950.0). On Jan. 6.66 UT the star appeared at mv = 12.3.
NOVA VULPECULAE 1987
Visual magnitude estimates by A. Boattini, Piazzano, Italy:
Jan. 1.73 UT, 8.2; 8.72, 9.3; 9.72, 9.4.
1988 January 11 (4526) Brian G. Marsden
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