Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Detections of simultaneous brightening of gamma-ray and optical
  emissions of a distant blazar GB 1508+5714 at redshift 4.3   GB 1508+5714 is a high-redshift blazar ($z$ = 4.3) and a spectrally soft
$\gamma$-ray source has been detected in its direction. By analyzing 11.4-yr
{\it Fermi}-LAT data, significant long-term variability of the $\gamma$-ray
source is confirmed. More importantly, a $\gamma$-ray emission flare appeared
in an epoch of several tens of days in year 2018, when the flux is about four
times of the value from the global fit. Meanwhile, optical flares displayed in
both $r$- and $i$-bands from the {\it Zwicky} Transient Facility light curves.
Detections of the simultaneous $\gamma$-ray and optical brightening provide a
decisive evidence to pin down the association between the $\gamma$-ray source
and GB 1508+5714, which makes it the {\it first} identified $\gamma$-ray blazar
beyond redshift 4. A broadband spectral energy distribution in the high flux
state is constructed and the origin of the multiwavelength brightening is also
briefly discussed. Upcoming wide-deep-fast optical telescopes together with the
$\gamma$-ray sky surveyors will shed lights on the role that the AGN jets play
in the early cosmic time.

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The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc
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The categories of this paper are: acc-phys
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The categories of this paper are: plasm-ph
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The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex