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IAUC 2760: 1975d; AL Com; SUSPECTED SN; CRAB PULSAR

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IAUC number 

                                                  Circular No. 2760
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Cable Address: SATELLITES, NEWYORK
Western Union: RAPID SATELLITE CAMBMASS


COMET BRADFIELD (1975d)
     A. C. Gilmore and P. M. Kilmartin, Carter Observatory, cable
the following precise positions, obtained with the 10-cm astrograph:

     1975 UT             R. A. (1950) Decl.        m1
     Mar. 18.33714     1 28 52.09   -21 23 59.7     9
          18.34611     1 28 55.11   -21 23 57.3


AL COMAE BERENICES
     Mr. C. Scovil, Stamford Museum, has reported another outburst
of this suspected U Gem-type variable (cf. IAUC 2666).  On Mar.
18.283 UT the visual magnitude was 12.8.  The outburst was confirmed
photographically.


SUSPECTED SUPERNOVA
     Dr. M. Schmidt, Hale Observatories, reports that J. P. Huchra
has discovered a suspected supernova 140" west and 120" north of
the nucleus of the galaxy Zw 1137.4+4613 (which are its 1950.0
coordinates).  The object was at mpg 14.5 when observed with the 46-cm
Schmidt telescope at Palomar on Mar. 16.266 UT, and a confirmatory
observation was made on Mar. 18.  Examination by Huchra of the
Palomar Sky Survey revealed at the position a faint object, of
magnitude 19 on the red plate and near the limit of the blue, so it is
possible that the object is a foreground variable.


CRAB PULSAR
     S. Ryckman, G. Ricker, A. Scheepmaker, J. Ballintine, J. Doty,
P. Downey and W. Lewin, Massachusetts Institute of Technology,
report: "During a balloon flight of an x-ray telescope on 1974 June
21 we observed the appearance of a previously unreported pulsed
feature in the light curve of the Crab pulsar NP 0532 in the energy
range from 35 to 115 keV.  This new peak precedes the so-called
primary pulse by approximately 12 ms between 19h58m and 20h03m UT
(> 3.5 sigma level of confidence) and between 20h41m and 20h48m (> 2.0
sigma).  It was not visible during the periods 15h02m to 15h24m,
20h28m to 20h37m and 21h30m to 21h43m.


1975 March 19                  (2760)              Brian G. Marsden

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