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IAUC 6516: GRO J2058+42; 1996bw; 1956C = 1988 XB5

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                                                  Circular No. 6516
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
Phone 617-495-7244/7440/7444 (for emergency use only)

GRO J2058+42
     A. J. Castro-Tirado, Laboratorio de Astrofisica Espacial y Fisica
Fundamental, Madrid, communicates: "We have examined the 8' RXTE error
box of the x-ray pulsar GRO J2058+42 (IAUC 6514) on a deep Schmidt plate
taken by K. Birkle at the German-Spanish Calar Alto Observatory on 1995
Oct. 15 in response to the report of the outburst on IAUC 6238.  On
that date, the pulsed signal was about 70 mCrab (C. A. Wilson, private
communication.).  A new object of mag about 18.5 not present on the
corresponding Palomar Sky Survey plate is seen at R.A. = 20h58m58s.0,
Decl. = +41d43'06" (equinox 2000.0, uncertainty +/- 1").  A second object
of mag about 19.5 that seems to be variable by about 0.5 mag is also seen
at R.A. = 20h59m07s.7, Decl. = +41d44'46".  A finding chart can be
obtained via anonymous ftp at laeff.esa.es (under /pub/users/ajct)."

     A. V. Filippenko, D. C. Leonard and W. Ho, University of
California at Berkeley, report that inspection of a CCD spectrum
(range 320-980 nm, resolution 0.7 nm) obtained on Dec. 7 with the
3-m Shane reflector at the Lick Observatory reveals that SN 1996bw is a
young type II (rather than type Ib; cf. IAUC 6512) supernova.  The
nearly featureless continuum is very blue, but weak, broad absorption
lines of H-beta and H-gamma are clearly visible.  There may be a
low-contrast, broad H-alpha emission line; the corresponding
absorption component is very weak.  M. Cavagna and F. Manca, Sormano,
Italy, have obtained the position R.A. = 1h43m44s.58, Decl. = +4d13'19".7
(equinox 2000.0).  G. J. Garradd, Loomberah, N.S.W., reports end figures
44.68, 20.0.  D. di Cicco, Sudbury, MA, reports end figures 44.48, 19.8
(with unfiltered CCD mag = 17.2-17.5 on Dec. 3.2 UT).

SUPERNOVA 1956C = 1988 XB5
     G. V. Williams, Center for Astrophysics, reports: "SN 1956C appears
to be the minor planet 1988 XB5 (5 oppositions, 1981-1996) near its
stationary point.  The object was discovered on a plate taken 1956
Feb. 10 for the Palomar Sky Survey that was subsequently rejected
(Kowal et al. 1971, PASP 83, 307).  The position of the galaxy
is given as R.A. = 12h43m.1, Decl. = +3d49' (equinox 2000.0), the presumed
supernova being of mpg = 17.6 and offset by 5" east, 27" south.  The
predicted positions of 1988 XB5 for 1956 Feb. 10.0 and 11.0 UT are
R.A. = 12h43m.18, Decl. = +3d47'.4 and 12h43m.26, +3d49'.5, respectively,
the predicted magnitude being V = 17.0."

                      (C) Copyright 1996 CBAT
1996 December 7                (6516)              Brian G. Marsden

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