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IAUC 5589: GRO J0422+32; 1991a1

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                                                  Circular No. 5589
Central Bureau for Astronomical Telegrams
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

GRO J0422+32
     R. M. Wagner and R. Bertram, Ohio State University; S. G.
Starrfield, Arizona State University; and C. R. Shrader, Computer
Sciences Corporation, report:  "Optical spectra of the candidate
reported on IAUC 5588 were obtained on Aug. 16.4 UT at the Perkins
1.8-m telescope with the Ohio State University CCD spectrograph.
The spectrum (range 440-720 nm, resolution 1.0 nm) shows emission
lines of He II 468.6-nm and N III 464.0-nm superposed on a blue
continuum.  These features are a characteristic of the optical
counterparts of various x-ray sources (see Bradt and McClintock
1983, Ann. Rev. A.Ap. 21, 13) and thus confirm the identification
of the x-ray source with the proposed optical object.  In addition,
broad and shallow Balmer absorption lines with weak emission cores
might also be present, but these features are less certain.
Additional observations, including more precise astrometry, are
     A. Goldwurm and J. Paul, Service d'Astrophysique, Saclay; P.
Mandrou and P. Techine, Centre d'Etude Spatiale des Rayonnements,
Toulouse; and R. Sunyaev, E. Churazov, M. Gilfanov, and A. Dyachkov,
Space Research Institute, Moscow, report for the SIGMA/Granat team:
"The soft gamma-ray transient GRO J0422+32 (IAUC 5580) has been
detected up to 400 keV by the coded-mask telescope SIGMA on the
Granat satellite, during a 16-hr observing session performed on Aug.
15-16.  The location is estimated to be at R.A. = 4h18m27s, Decl. =
+32 48'.0 (equinox 1950.0), with an error radius of about 2'.  The
SIGMA error circle includes the probable optical counterpart proposed
by Castro-Tirado et al. (IAUC 5588).  The average flux relative
to the Crab Nebula in the energy bands 40-74, 74-154, and 154-
282 keV was 2.8, 2.9, and 2.2, respectively.  Monitoring of the
source is continuing."

     Total visual magnitude estimates (cf. IAUC 5571):  July 24.93
UT, 8.5 (J. Shanklin, Cambridge, England, 0.2-m refractor); 31.86,
8.1 (S. Garro, Merlette, France, 12x80 binoculars); Aug. 1.83, 8.1
(H. Dahle, Khania, Crete, 0.20-m reflector); 2.92, 8.1 (V. F. de
Assis Neto, Sao Francisco de Oliveira, Brazil, 10x70 binoculars);
5.10, 8.8 (G. W. Kronk, Troy, IL, 0.33-m reflector).

1992 August 17                 (5589)            Daniel W. E. Green

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