Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Detection of Low-Frequency QPO From X-ray Pulsar XTE J1858+034 During
  Outburst in 2019 with NuSTAR   We study the timing properties of XTE J1858+034 using the Nuclear
Spectroscopic Telescope Array (NuSTAR) and Burst Alert Telescope onboard Swift
during the outburst in October--November 2019. We have investigated for
Quasi-Periodic Oscillation (QPO) during the outburst and detected a
low-frequency QPO at $\sim$196 mHz with $\sim$6% RMS variability from the
NuSTAR observation. The QPO is fitted and explained with the model - power law
and a Lorentzian component. We have also studied the variation of QPO frequency
with energy. The beat frequency model and Keplerian frequency model both are
suitable to explain the origin of the QPOs for the source. Regular pulsations
and QPOs are found to be stronger in high energy which suits the beat frequency
model. The variation of the hardness ratio is studied over the outburst which
does not show any significant variation.

10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
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The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys