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IAUC 7016: 1998eb; XTE J1946+274, 3A 1942+274; C/1997 J2

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                                                 Circular No. 7016
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
URL http://cfa-www.harvard.edu/iau/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)

SUPERNOVA 1998eb IN NGC 1961
     W. D. Li, M. Modjaz, E. Halderson, T. Shefler, J. Y. King, M.
Papenkova, R. R. Treffers, and A. V. Filippenko, University of
California at Berkeley, report their discovery of an apparent
supernova in NGC 1961 during the course of the Lick Observatory
Supernova Search (cf. IAUC 6627) with the 0.8-m Katzman Automatic
Imaging Telescope (KAIT).  SN 1998eb was found and confirmed on
unfiltered images taken on Sept. 17.5 and 19.4 UT (unfiltered
magnitude about 17.8), respectively.  The object, is located at
R.A. = 5h42m12s.02, Decl. = +69o22'26".3 (equinox 2000.0), which is
about 38".8 east and 17".0 south of the nucleus of NGC 1961.  A
KAIT image of NGC 1961 obtained on Mar. 9.2 shows nothing at the
position of SN 1998eb (limiting mag about 18.5).

XTE J1946+274 AND 3A 1942+274
     T. Takeshima, NASA/Goddard Space Flight Center and
Universities Space Research Association; and D. Chakrabarty,
Massachusetts Institute of Technology, report:  ''Scans of the
region containing this transient x-ray pulsar (IAUC 7014) with the
Proportional Counter Array (PCA) onboard RXTE on Sept. 16.23 UT
have yielded the following improved position for the x-ray source:
R.A. = 19h45m34s, Decl. = +27o23'.0 (equinox 2000.0).  The error
radius of 2'.4 (90-percent confidence level) is dominated by
systematic uncertainties due to source intensity variations during
the scans.  The error circle almost includes the overlap of the
RXTE/ASM error box for XTE J1946+274 (IAUC 7014) and the long Ariel
V error strip for 3A 1942+274 (Warwick et al. 1981, MNRAS 197, 865).
This strongly suggests that the two sources are identical.  During
the PCA observations on Sept. 16.24 and 17.57, the average source
flux level and the pulse fraction stayed at about 110 mCrab and
about 30 percent, respectively (2-60 keV).  Observations at other
wavelengths are encouraged in order to identify the mass donor."
     Corrigendum.  On IAUC 7014, line 30, for  2.2(2) x 10E-12
Hz/s  read  8.7(9) x 10E-12 Hz/s

     Total visual magnitude estimates:  Aug. 3.29, 11.0 (C. E.
Spratt, Victoria, BC, 0.20-m reflector); 19.87, 11.3 (M. Meyer,
Frauenstein, Germany, 0.25-m reflector); Sept. 9.81, 11.2 (K.
Hornoch, Lelekovice, Czech Republic, 0.35-m reflector); 18.04, 11.8
(J. Bortle, Stormville, NY, 0.41-m reflector).

                      (C) Copyright 1998 CBAT
1998 September 19              (7016)            Daniel W. E. Green

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