4U 1715-390 and NGC 6440 in Outburst
ATel #495; C. B. Markwardt (NASA/GSFC and U. Maryland), J. H. Swank (NASA/GSFC)
on 18 May 2005; 14:53 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Craig B. Markwardt (craigm@lheamail.gsfc.nasa.gov)
Subjects: X-ray, Globular Cluster, Neutron Star, Transient
Referred to by ATel #: 2360
RXTE Proportional Counter Array scans of the galactic bulge region
have been continuing.
The burster in the globular cluster NGC 6440 (MXB 1746-20) appears to
be entering outburst. The previous outburst was in October 2001. The
2-10 keV fluxes on May 12.6, 15.6 and 16.1 were 5.4 +/- 1.0, 7 +/- 3
and 21 +/- 1 mCrab, respectively. We appreciate inquiries by J. in 't
Zand and R. Wijnands about this source.
The X-ray source 4U 1715-39 also may be starting an outburst. Scans
on May 16.2 indicate a rise in flux of 4 mCrab (the baseline flux
level is somewhat uncertain). Based on a Simbad reference search,
little is known about this source aside from its detection, last
reported in the HEAO A-1 catalog.
The source 4U 1850-087, in the globular cluster NGC 6712, reached a
peak of 8 mCrab on April 3, 2005, after a gradual rise starting in May
2004. It is still at 4 mCrab.
