Central Bureau for Astronomical Telegrams
IAUC 6840: AX J0049-729 = RX J0049.1-7250; SAX J1818.6-1703, KS 1741-293
The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).
Read IAUC 6841
.dvi or
.ps format.
Circular No. 6840
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
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
Read IAUC 6841
.dvi or
.ps format.
Our Web policy. Index to the CBAT/MPC/ICQ pages.
