IGR J11435-6109: Faded, but Variable - Possibly ~ 166 s Pulsations
ATel #359; J. H. Swank(GSFC) and C. B. Markwardt(U Maryland and GSFC)
on 7 Dec 2004; 03:04 UT
Credential Certification: Jean Swank (email@example.com)
Subjects: X-ray, Binary, Transient, Pulsar
The title of ATEL #358 was a product of submission error. Please ignore.
On Dec. 4, 2004 at 03:42 UT RXTE observed the source IGR
J11435-6109 that was recently discovered with INTEGRAL's IBIS/ISGRI.
(ATEL #350). The pointing position was offset to insure no
contribution in the PCA from nearby 4U 1145-619 and 1E1145.1-6141. An
average net count rate of 1.7/s was observed over 896 s. Variations
of about 50% were notable, which could be due to a noisy pulsation. In
a Lomb Scargle Periodogram, the strongest peak is at 166 s (and thus
the data included only 5 periods). The spectral data were fit with an
absorbed power law with a column density < 1e23 cm-2 (3 sigma) and a
photon index of 2.3+/-0.4. The implied fluxes were 4.0e-11 and 1.6e-11
ergs cm-2 s-1 for 2-10 and 10-20 keV respectively. The source was an
order of magnitude fainter than reported by Grebenev et al. on
Nov. 23, 2004 (ATEL #350).
RXTE cannot make additional observations of the source at this