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IAUC 7126: 1999 E1; 4U 0115+63

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                                                  Circular No. 7126
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7244/7440/7444 (for emergency use only)


COMET 1999 E1
     Weidong Li and M. Modjaz, Department of Astronomy, University
of California at Berkeley, report the discovery of a comet in the
course of the Lick Observatory Supernova Search (cf. IAUC 6627;
with the participation of J. Y. King, M. Papenkova, R. A. Johnson,
A. Friedman, R. R. Treffers and A. V. Filippenko).  The object was
found automatically by the Katzman Automatic Imaging Telescope
(KAIT), recorded by Modjaz as a supernova candidate, and recognized
by Li as a comet.  Li then used the equipment to make confirmatory
observations three nights later.  The comet shows an apparent tail
in p.a. about 120 deg.  Available unfiltered CCD astrometry:

     1999 UT             R.A. (2000) Decl.        m1
     Mar. 13.17569    6 24 42.94   + 4 41 24.2   16.5
          16.14473    6 25 40.92   + 5 16 38.0   16.8
          16.16436    6 25 41.29   + 5 16 51.7   16.7
          16.19431    6 25 41.93   + 5 17 12.7   16.8


4U 0115+63
     W. A. Heindl and W. Coburn, University of California, San
Diego, report:  "The current outburst of the 3.6-s x-ray pulsar 4U
0115+63 (IAUC 7116) has been monitored with daily RXTE pointings
since Mar. 3.  The flux (2-10 keV) has increased from 5.6 x 10E-9
(Mar. 3) to 1.1 x 10E-8 erg cmE-2 sE-1 on Mar. 12.  Fitting the
Mar. 3 joint PCA/HEXTE spectrum reveals cyclotron absorption
features at about 14 and 21 keV.  Because the phase-averaged
spectra are complex due to pulse-phase spectral variability, these
line energies are not well-determined.  A cyclotron absorption
feature was first seen in this source with HEAO 1 (Wheaton et al.
1979, Nature 282, 240).  In addition to the short monitoring
observations, we have made two long pointings on Mar. 7.16-7.45 and
11.89-12.32 UT.  The second of these spanned periastron passage
(according to the ephemeris of Bildsten et al. 1997, Ap.J. Suppl.
113, 367) at Mar. 11.95.  During this observation, the source
exhibited large oscillations with a timescale of about 500 s.  The
oscillation rms deviations were about 30 percent of the mean flux.
Such slow oscillations are not consistent with the beat-frequency
QPO model whose expected frequencies are of order 5 Hz.  The
oscillations may have been present during 2500 s of the Mar. 7
observation, but at greatly reduced amplitude.  Additional
observations are encouraged.  The RXTE/ASM real-time light curve
is available at http://heasarc.gsfc.nasa.gov/xte_weather/."

                      (C) Copyright 1999 CBAT
1999 March 16                  (7126)            Daniel W. E. Green

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