Central Bureau for Astronomical Telegrams
IAUC 4389: 1987A; EXO 165228+3930.3
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Circular No. 4389
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
A. Chalabaev, Observatoire de Haute Provence; C. Perrier,
Observatoire de Lyon; and P. Bouchet, European Southern Observatory,
La Silla, telex: "Infrared speckle observations of SN 1987A were
obtained with the ESO 3.6-m telescope on May 8 and 9 in bad seeing
conditions (3"-4" in V). We used an L (3.4 microns) filter.
Preliminary reduction of part of the data shows that, at the level of 10
percent of the total flux, there are no resolved sources. At this
flux level, the 3-sigma upper limit on the width of an extended halo,
which one would expect from an infrared light echo, is 0".30."
R. H. McNaught, Coonabarabran, N.S.W., reports the following
photovisual measures, corrected for dependence on B-V, obtained
from exposures centered on the times given: Feb. 23.444 UT, 6.36 +/-
0.15 (McNaught, mean of two sequential exposures of two-min
duration, Tri-X and minus-violet filter; cf. IAUC 4316); Feb 23.62,
6.11 +/- 0.15 (F. Zoltowski, Woomera, S. Australia, slightly-
trailed 11-min exposure, 135-mm lens, hypered Konica 400 film).
EXO 165228+3930.3
L. Bassani, E. Caroli, J. B. Stephen, and G. Di Cocco, Istituto
TESRE, Consiglio Nazionale delle Ricerche, Bologna, report: "We
have found a new source, EXO 165228+3930.3, at high galactic latitude
(R.A. = 16h52m27.9, Decl. = +39 30'20.2, equinox 1950.0, error radius
20"). The source, which lies about 20' south of the observed target
(Markarian 501), was detected in only 3 observations (at > 5 sigma
confidence level) out of a total of 8 measurements taken by the Low
Energy Experiment (LE1/CMA) on board EXOSAT during 1984. The
object was found on exposures taken with the thin Lexan (0.0113 +/-
0.0014 cts/s) and Al/Parylene (0.0045 +/- 0.0015 cts/s) filters. The
same object was detected previously as a serendipitous Einstein
source (at R.A. = 16h52m27.5, Decl. = +39 30'43.9, equinox 1950.0, error
radius 60"), but its detection was never reported in the literature.
Two Imaging Proportional Counter (IPC) observations included
this object in the field of view of the instrument: Sequence No.
I5210, made on 1980 Jan. 19-20, gave a source intensity of 0.038 +/-
0.005 IPC cts/s, and Sequence No. I5211, made on 1980 Aug. 15, gave
a source intensity of 0.042 +/- 0.009 IPC cts/s. The interest in the
object lies in its possible association with the far-infrared
source IRAS 1652+39.5 (Bassani et al. 1986, ESA SP-260, 151)."
1987 May 13 (4389) Daniel W. E. Green
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