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IAUC 5764: GRO J0422+32; GRB 930309; S Aps

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                                                  Circular No. 5764
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@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)


GRO J0422+32
     C. Chevalier and S. A. Ilovaisky, Observatoire de Haute-
Provence; and R. M. Wagner, Ohio State University, report:  "We
confirm that a rapid decrease in brightness of the optical counterpart
of GRO J0422+32 took place during the first half of April.  A
spectrum taken with the 1.8-m Perkins telescope at Lowell Observatory
on Apr. 7.1 UT showed H-alpha, H-beta, and very weak He II
468.6-nm emission, with the object being at mag about 15-16.  CCD
photometry obtained with the 1.2-m Haute-Provence telescope on Apr.
8.8 and 11.8 UT yielded V = 16.2 and 16.6, respectively.  Our
observations, combined with the estimate of Filippenko and Matheson
(IAUC 5761), indicate a final decline rate of 0.3-0.4 mag/day.  The
total duration of the optical outburst of this source (about 250
days since x-ray turn-on) is remarkably close to that observed in
V616 Mon (A0620-00) in 1975-76."


GRB 930309
     A. J. Beasley, K. S. Dwarakanath, and M. P. Rupen, National
Radio Astronomy Observatory, report:  "VLA snapshot observations on
Apr. 9.93 (1425 MHz) and 14.93 UT (330 and 1425 MHz) of the radio
source previously associated with GRB 930309 (IAUC 5749, 5750)
indicate an extended source consisting of two lobe-like components.
The components are located at R.A. = 21h31m16s.3, Decl. =
+54 26'55".4 and 21h32m14s.6, +54 27'11".9 (equinox 1950.0), with
integrated 1425-MHz flux densities of 9.7 +/- 0.2 and 6.6 +/- 0.2
mJy, respectively (1-sigma errors).  There is no evidence for
significant variation in either component between the 1425-MHz
observations. At 330 MHz, we detect an extended source with an
integrated flux density of 154.9 +/- 6 mJy, implying a combined
spectral index alpha about -1.5 (nuEalpha).  This index is also
consistent with the 49-cm flux density and 6-cm upper limit reported on
IAUC 5749.  The source appears to be an extragalactic background
source, presumably unrelated to GRB 930309 (cf. IAUC 5763)."


S APODIS
     P. M. Kilmartin, A. C. Gilmore, and P. L. Cottrell, Mt. John
University Observatory, provide the following photoelectric measures
of this fading R CrB-type star (all measures +/- 0.02 mag):
Mar. 28.48 UT, V = 9.87, B-V = +1.15; Apr. 1.39, 10.03, +1.19;
5.40, 10.22, +1.22; 6.39, 10.28, +1.19; 11.46, 10.61, +1.22; 14.44,
10.88, +1.24.


1993 April 16                  (5764)            Daniel W. E. Green

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