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IAUC 6840: AX J0049-729 = RX J0049.1-7250; SAX J1818.6-1703, KS 1741-293

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                                                 Circular No. 6840
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)

AX J0049-729 = RX J0049.1-7250
     P. Kahabka, University of Amsterdam, and W. Pietsch, Max-
Planck-Institut fur Extraterrestrische Physik, communicate:  "The
new x-ray pulsar in the Small Magellanic Cloud reported by Yokogawa
and Koyama (IAUC 6835) coincides in position (within the 2' error
circle) with the ROSAT source RX J0049.1-7250 (Kahabka and Pietsch
1996, A.Ap. 312, 919).  The source is highly variable and has been
detected during ROSAT PSPC observations on 1991 Oct. 9 and 1992
Apr. 15-24, but it was not detected during a 35~000-s ROSAT HRI
observation on 1997 May 9-25.  A mean source position derived from
reprocessed archival ROSAT data is R.A. = 0h49m02s.3, Decl. =
-72o50'55" (equinox 2000.0; +/- 13" at 90-percent confidence).  The
source may be a Be-type transient.  Optical identification work is
highly encouraged."

SAX J1818.6-1703 AND KS 1741-293
     J. in 't Zand and J. Heise, Space Research Organization of the
Netherlands (SRON), Utrecht; M. Smith, BeppoSAX Science Operation
Center, Rome, and SRON; J. M. Muller, BeppoSAX Science Data Center,
Rome, and SRON; and P. Ubertini and A. Bazzano, Istituto di
Astrofisica Spaziale, CNR, Rome, report:  "In an observation of the
galactic bulge with Wide Field Camera 2 onboard BeppoSAX during Mar.
10.2-12.0 UT, two interesting x-ray sources were detected other
than SAX J1810.8-2609 (IAUC 6838).  One was seen to turn on at Mar.
11.8 and peak at Mar. 11.86 at a level of 0.1 Crab in 2-9 keV and
0.4 Crab in 9-25 keV (as measured over 15-min time bins).  Over the
last 40 min of the observation, the intensity is at least twice as
low.  The 3-sigma upper limits for the pre-flare part of the 2-day
observation are 10 and 35 mCrab in these respective energy bands.
The position is R.A. = 18h18m39s, Decl. = -17o03'.1 (equinox 2000.0,
preliminary error radius 3').  No catalogued x-ray source is within
the error box, and we designate this new transient SAX J1818.6-1703.
The error box contains one catalogued optical star, HD 168078 (a B3
III star with m_v = 10.7).  Another hard source was detected at R.A.
= 17h44m40s, Decl. = -29o20'.5 (preliminary error radius 3').
There is one catalogued x-ray source in the error box, KS 1741-293
(a burst source first identified in 1989 and not detected since).
Intensities are 6 mCrab in 2-9 keV and 25 mCrab in 9-25 keV.  The
intensity appears constant within about 30 percent on a timescale of
half a day.  Further observations are encouraged for both sources."

                      (C) Copyright 1998 CBAT
1998 March 13                  (6840)            Daniel W. E. Green

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