INTEGRAL observations of the gamma-ray binary 1FGL J1018.6-5856
Abstract
The Fermi-LAT collaboration has recently reported that one of their detected sources, namely, 1FGL J1018.6-5856, is a new gamma-ray binary similar to LS 5039. This has prompted efforts to study its multi-frequency behavior. In this report, we present the results from 5.78-Ms INTEGRAL IBIS/ISGRI observations on the source 1FGL J1018.6-5856. By combining all the available INTEGRAL data, a detection is made at a significance level of 5.4 sigma in the 18-40 keV band, with an average intensity of 0.074 counts/s . However, we find that, there is non-statistical noise in the image that effectively reduces the significance to about 4 sigma and a significant part of the signal appears to be located in a 0.2-wide phase region, at phases 0.4-0.6 (where even the corrected significance amounts to 90% of the total signal found). Given the scarcity of counts, a variability is hinted at about 3 sigma at the hard X-rays, with an anti-correlation with the Fermi-LAT periodicity. Should this behavior be true, it would be similar to that found in LS 5039, and prompt observations with TeV telescopes at phases anti-correlated with the GeV maximum.
Cite
@article{arxiv.1108.1668,
title = {INTEGRAL observations of the gamma-ray binary 1FGL J1018.6-5856},
author = {Jian Li and Diego F. Torres and Yupeng Chen and Diego Götz and Nanda Rea and Shu Zhang and G. Andrea Caliandro and Jianmin Wang},
journal= {arXiv preprint arXiv:1108.1668},
year = {2015}
}
Comments
Accepted for publication in Astrophysical Journal Letters; 6 pages, 1 figure