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IAUC 6829: 1998S; PSR J1024-0719; 69P

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                                                 Circular No. 6829
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)

     W.-d. Li, University of California at Berkeley, forwards a
report from C. Li, Beijing Astronomical Observatory (BAO), that
Zhou Wan has found an apparent supernova (unfiltered mag 15.2) on
CCD images obtained with the 0.60-m BAO telescope on Mar. 3 UT as
part of the BAO Supernova Survey (cf. IAUC 6612).  A confirming CCD
observation made with the Katzman Automatic Imaging Telescope
(KAIT) of Lick Observatory by the Lick Supernova Survey (cf. IAUC
6627) indicates that the object has brightened to unfiltered mag
about 13.5 on Mar. 4.3 UT.  SN 1998S is located at R.A. =
11h46m06s, Decl. = +47o29'.0 (equinox 2000.0; based on the KAIT
image), which is 16" west and 46" south of the nucleus of NGC 3877.
As the object is embedded in the galaxy, the BAO magnitude was
obtained from a subtracted image.  SN 1998S is not present in
images of the same field taken prior to Mar. 3.
     A. V. Filippenko and E. C. Moran, University of California at
Berkeley, obtained a very-high-resolution (0.015 nm) echelle
spectrogram of SN 1998S on Mar. 4 with the Keck-1 telescope.  The
probable presence of broad H-alpha emission superposed on a
featureless continuum suggests that this is a type-II supernova.

PSR J1024-0719
     W. Becker and J. Trumper, Max-Planck-Institut fur
Extraterrestrische Physik, report:  "We have detected the isolated
galactic millisecond pulsar PSR J1024-0719 in the energy range
0.1-2.4 keV with ROSAT.  The source was observed with the High
Resolution Imager (HRI) from 1997 Nov. 17 to Dec. 7 for a total
exposure time of 80~635 s.  The net countrate (including background,
vignetting and dead-time corrections) is (3.3 +/- 0.3) x 10E-4
counts/s.  Assuming a Crab-like spectrum and a column absorption of
N_H = 2 x 10E20 cmE-2, deduced from the radio dispersion measure
(cf. Bailes et al. 1997, Ap.J. 481, 386), we find an energy flux of
2 x 10E-14 erg sE-1 cmE-2 over 0.1-2.4 keV.  The low number of
recorded source counts precluded any modulation testing at the
5.15-ms radio period."

     Visual m_1 estimates:  Feb. 14.83 UT, 11.3 (A. Kammerer,
Ettlingen, Germany, 0.20-m reflector); 27.05, 11.8 (J. Bortle,
Stormville, NY, 0.41-m reflector); Mar. 1.78, 11.8 (V. Znojil, Brno,
Czech Rep., 25x100 binoculars).

                      (C) Copyright 1998 CBAT
1998 March 4                   (6829)            Daniel W. E. Green

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