[ Previous | Next | ADS ]

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 (swank@milkyway.gsfc.nasa.gov)

Subjects: X-ray, Binary, Transient, Pulsar

Referred to by ATel #: 370, 377, 531, 1231

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 time.