Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Swift observations of 1FGL J1018.6-5856   We report on X-ray properties of the gamma-ray binary 1FGL J1018.6-5856 using
observations obtained with the Swift X-ray telescope. Using 54 observations
made between MJD 55575 and 55984, we find that the X-ray flux is modulated at a
period of 16.57 +/- 0.11 days, consistent with previous reports based on
gamma-ray data. We find that the X-ray maximum at phase 0 previously reported
may not be a persistent feature of the source: the dramatic increases at phase
0 were detected only for ~100 days and not thereafter. Rather, the persistent
sinusoidal maximum seems to be at phase 0.3--0.4, and is misaligned with the
gamma-ray (GeV) peak. We also find evidence that the source's X-ray flux is
correlated with the spectral hardness in the 0.5--10 keV band. Such a
correlation has also been reported in the gamma-ray binaries LS 5039 and LS
I+61d303 and can help us to understand the X-ray emission mechanisms of the
sources.

8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex