Central Bureau for Astronomical Telegrams
IAUC 4340: 1987A
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Read IAUC 4341
Circular No. 4340
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
R. Svoboda, University of California, Irvine, on behalf of
the Irvine-Michigan-Brookhaven (IMB) collaboration, reports: "A
signal was observed in data from a nucleon decay detector near
Cleveland, Ohio (long. -81.3, lat. +41.7), on Feb. 23d07h35m41s.4 UT.
Eight events were recorded in a 6-s interval, five of them during
the first 2 s. The events are consistent with neutrino interactions
of energies < 50 MeV. The IMB imaging water Cerenkov detector
has an effective mass of 4000 tonnes and is capable of measuring
neutrino interactions with good precision. The normal event
rate in the detector from neutrinos produced by cosmic rays in the
upper atmosphere is 1/day. The signal is coincident with a similar
observation reported by the Kamioka collaboration (IAUC 4338)."
R. H. McNaught, Siding Spring Observatory, informs us that A.
Jones (Nelson, New Zealand), who easily discovered the supernova
visually on Feb. 24.37 UT (IAUC 4316) with a 30 x 78 finder
telescope, did not notice the object with the same instrument on Feb.
23.39 UT, suggesting that it was then fainter than mag 7.5.
P. Barrett, University of Cape Town, reports that further
polarimetry (cf. IAUC 4337) shows that the polarization appears to
have stabilized after a decrease during the past week, possibly
indicating that a thin dust shell surrounds the supernova. The
result cannot be confirmed because the polarization of the
comparison star has decreased by a similar amount.
1987 U B V R(C) I(C)
Mar. 7 P 0.79 (12) 0.74 (4) 0.76 (7) 0.71 (8) 0.60 (7)
O 41 (12) 39 (4) 37 (8) 31 (9) 35 (10)
V +0.14 (8) +0.01 (3) +0.01 (5) -0.01 (5) +0.01 (5)
Mar. 8 P 0.83 (11) 0.72 (5) 0.71 (8) 0.73 (9) 0.66 (9)
O 44 (11) 40 (6) 36 (9) 36 (10) 38 (11)
V +0.07 (8) -0.07 (4) 0.00 (5) -0.01 (6) -0.03 (6)
Visual magnitude estimates: Mar. 10.41 UT, 4.2 (T. Beresford,
(Adelaide, S. Australia); 10.41, 4.4 (R. H. McNaught,
Coonabarabran, N.S.W.); 10.42, 4.3 (G. Garradd, Tamworth, N.S.W.).
Corrigenda. IAUC 4330, line 7, for 833 read 883. IAUC 4339,
line 19, add the names of the observers B. N. Ashvka, G. C.
Anupama, K. K. Ghosh, S. K. Jain, A. K. Pati and T. P. Prabhu.
1987 March 11 (4340) Brian G. Marsden
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