Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Multi-scale VLBI observations of the candidate host galaxy of GRB
  200716C   In this Letter we present the analysis of multi-band public data and high
sensitivity EVN and e-MERLIN follow-up observations of the candidate host
galaxy of GRB 200716C, namely J1304+2938. GRB 200716C is a long-duration
$\gamma$-ray burst (GRB), which surprisingly lies among the short-duration GRBs
in the E$_{iso}$-E$_{p,z}$ Amati relation. Because of this property and the
presence of two peaks in the $\gamma$-ray light curve, it has been recently
suggested that GRB 200716C might be a short-GRB gravitationally lensed by an
intermediate-mass black hole (IMBH) hosted by J1304+2938 at z = 0.341. While no
detections of the afterglow have been reported in radio hitherto, we present
here the discovery of significant emission in survey data between 130 MHz and 3
GHz, together with the results of deep, dedicated high-angular-resolution
observations carried out with EVN+e-MERLIN, which do not reveal any significant
emission down to the $\sim$10 uJy beam$^{-1}$ level. We associate the radio
emission to J1304+2938, and we derive a luminosity larger than (2.9$\pm$0.4)
$\times$ 10$^{30}$ erg s$^{-1}$ Hz$^{-1}$: if GRB 200716C belongs to
J1304+2938, the latter would be one of the brightest host galaxy detected so
far in the radio. As a matter of fact, altogether the properties of J1304+2938
are consistent with a highly star forming galaxy (SFR > 186 M$_{\odot}$
yr$^{-1}$), which is the typical environment expected for long-GRBs.
Conversely, neither the public data nor our VLBI observations can confirm or
rule out the presence of an IMBH acting as a (milli-)lens, and thus the nature
of the burst still remains unknown.

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The categories of this paper are: funct-an
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The categories of this paper are: ao-sci
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The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom
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The categories of this paper are: plasm-ph
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The categories of this paper are: solv-int
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The categories of this paper are: cmp-lg
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The categories of this paper are: nlin
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-ex
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The categories of this paper are: mtrl-th
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The categories of this paper are: patt-sol
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The categories of this paper are: supr-con
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The categories of this paper are: atom-ph
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The categories of this paper are: math
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The categories of this paper are: chao-dyn