Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Probing the origin of low-frequency radio emission in PG quasars with
  the uGMRT -- I   We present the results from 685 MHz observations with the upgraded Giant
Metrewave Radio Telescope (uGMRT) of 22 quasars belonging to the Palomar-Green
(PG) quasar sample. Only four sources reveal extended radio structures on
$\sim$10-30 kpc scales, while the rest are largely a combination of a radio
core unresolved at the uGMRT resolution of $\sim$3-5 arcsec, surrounded by
diffuse emission on few kpc to $\sim$10 kpc scales. A few sources reveal
signatures of barely resolved jets and lobes in their spectral index images
that are created using the uGMRT 685 MHz data and similar resolution
GHz-frequency data from the Very Large Array. On the basis of their position on
the radio-IR correlation as well as the spectral index images, we find that the
radio emission in the two radio-loud (RL) quasars and nearly one-third of the
radio-quiet (RQ) quasars is active galactic nucleus (AGN) dominated whereas the
remaining sources appear to have significant contributions from stellar-related
processes along with the AGN. While the two RL sources exhibit inverted
spectral index in their cores, the RQ sources exhibit a range of spectral
indices varying from flat to steep ($-0.1\gtrsim\alpha_{R}\gtrsim-1.1$)
indicating the presence of unresolved jets/lobes or winds. Except for a
significant correlation between the 685~MHz radio luminosity and the Eddington
ratio, we do not find strong correlations between other 685 MHz radio
properties and black hole (BH) properties in the RQ PG sources. This lack of
correlations could be explained by the contribution of stellar-related
emission, or radio emission from previous AGN activity episodes which may not
be related to the current BH activity state.

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The categories of this paper are: q-alg
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: physics
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The categories of this paper are: gr-qc
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The categories of this paper are: q-bio
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The categories of this paper are: hep-ex
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The categories of this paper are: cs
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The categories of this paper are: hep-th
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The categories of this paper are: econ
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The categories of this paper are: quant-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: q-fin
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The categories of this paper are: chem-ph
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The categories of this paper are: supr-con