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IAUC 5437: 1992B; GRS 0834-430; N Pup 1991

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                                                  Circular No. 5437
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

     C. Pollas, Observatoire de la Cote d'Azur, reports his discovery
of an apparent supernova (mpv = 17.8) found on technical pan
films taken on Jan. 14.2 and 15.2 UT.  SN 1992B is located at R.A. =
11h13m17s.03, Decl. = +55 45'52".9 (equinox 1950.0), or 12".7 east
and 4".5 north of the nucleus of a spiral galaxy of mag 16.5.  A
nearby star of mag 16 has end figures 13s.50, 54".5.  The limiting
magnitude of the films is 22, and nothing is seen on the POSS prints
(limiting mpv = 20.5).

GRS 0834-430
     R. Sunyaev, S. Grebenev, M. Dennis, and A. Goldwurm, on behalf
of the Granat team (Space Research Institute, Moscow; Service
d'Astrophysique, Centre d'Etudes Nucleaires de Saclay; Centre d'Etude
Spatiale des Rayonnements, Toulouse), report:  "The transient x-ray
pulsar GRS 0834-430 (IAUC 5139, 5142, 5180, etc.) was observed with
instruments onboard Granat on 1991 Dec. 18 and was found to be in a
bright state.  Its x-ray flux was 94 +/- 4 and 174 +/- 8 mCrab in
the ART-P 6- to 15-kev and 15- to 35-keV energy bands and 44 +/- 8
mCrab in the SIGMA 35- to 100-keV band.  The source had a power-law
spectrum with a photon index of -1.04 +/- 0.03, which cut off abruptly
at energies > 30 keV; in the 35- to 100-keV bands, the photon index
was about -4.7 +/- 1.0.  The barycentric period of x-ray pulsations
was found to be 12.3073 +/- 0.0001 s (on Dec. 18.6 UT), indicating
that the pulsar continued to spin up with period derivative
P-dot/P about -1.7 x 10E-3 yrE-1 (IAUC 5294).  The 1991 December
outburst became the fifth x-ray outburst detected from GRS 0834-430
since its discovery by the WATCH instrument onboard Granat in 1990
February (IAUC 5122)."

     Visual magnitude estimates (cf. IAUC 5423): Jan. 10.642 UT, 8.8
(S. Sakuma, Kawasaki, Japan); 12.1, 9.0 (J. Smit, Waverly, South
Africa); 13.184, 8.9 (P. Steffey, Daytona Beach, FL); 14.16, 8.6 (M.
Adams, Melbourne, FL); 15.55, 9.2 (A. Pearce, Scarborough, W.
Australia); 18.8, 9.2 (Smit); 19.25, 9.1 (R. Hays, Worth, IL); 20.35,
9.1 (R. Royer, Lakewood, CA); 22.53, 9.5 (Pearce).

1992 January 23                (5437)             Daniel W. E. Green

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