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IAUC 6046: X-RAY N IN Sco; 1994W

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                                                  Circular No. 6046
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

     S. N. Zhang, C. A. Wilson, B. A. Harmon, G. J. Fishman, R. B.
Wilson, W. S. Paciesas, M. Scott, and B. C. Rubin report for the
Compton Gamma Ray Observatory BATSE team:  "An x-ray nova has been
observed at R.A. = 16h55m, Decl. = -40o.5 (equinox 2000.0; error
radius 0o.3).  The source (GRO J1655-40) first appeared in data
from July 27 and has increased to its present level of about 1.1
Crab (20-100 keV) on Aug. 1.  Significant flux is observed to 200
keV.  A power law with a spectral index of -3.15 +/- 0.07 fits the
data well from 20 to 200 keV.  Pulsed emission is not seen in the
period range from 3 to 300 s at a limiting sensitivity of about 10
percent of the steady flux.  No previously-cataloged x-ray source
is known at this location.  It has also been determined that the
nearby x-ray pulsar OAO 1657-415, currently observed by BATSE, is
not responsible for the observed emission."

     A. V. Filippenko and A. J. Barth, University of California at
Berkeley, report:  "A CCD spectrogram (range 425-704 nm, resolution
0.7 nm), obtained on Aug. 4 with the Shane 3-m reflector at Lick
Observatory, confirms that SN 1994W is a peculiar type-II supernova
(cf. IAUC 6044).  Relatively narrow (FWHM = 1200 km/s) hydrogen
Balmer emission lines are superposed on much broader bases (FWZI =
7500 km/s); broad (FWHM about 5000 km/s) He I 587.6-nm emission is
also visible, with no narrow component.  Narrow Fe II emission
lines are weaker but present.  Unlike the case in normal type-II
supernovae, the Balmer lines do not show broad P-Cyg absorption.
However, they do exhibit narrow (FWHM = 300 km/s) P-Cyg absorption
components with minima displaced by 700 km/s from the emission-line
cores.  Similar features are seen in some of the Fe II lines,
especially those of multiplet 42; they may be produced by a wind
from the progenitor.  Previous supernovae showing such characteristics
have often been strong radio sources, due to interaction of
the ejecta with dense circumstellar gas.  Further observations at
all wavelengths are encouraged.  Note that the offsets reported by
Richmond et al. (cf. IAUC 6043) were based on a slightly incorrect
value for the pixel scale; SN 1994W is actually 7".3 west and 17".7
north of the nucleus, consistent with the values given by Pollas

1994 August 4                  (6046)            Daniel W. E. Green

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