Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A search for dust and molecular gas in enormous Ly$\alpha$ nebulae at
  $z\approx 2$   Enormous Ly$\alpha$ nebulae, extending over 300-500\,kpc around quasars,
represent the pinnacle of galaxy and cluster formation. Here we present IRAM
Plateau de Bure Interferometer observations of the enormous Ly$\alpha$ nebulae
`Slug' ($z$=$2.282$) and `Jackpot' ($z$=$2.041$). Our data reveal bright,
synchrotron emission associated with the two radio-loud AGN embedded in the
targeted nebulae, as well as molecular gas, as traced via the CO(3-2) line, in
three galaxies (two sources in the Slug, and one in the Jackpot). All of the CO
emission is associated with galaxies detected in their rest-frame UV stellar
emission. The total mass in molecular gas of these three galaxies [$\sim
(3-5)\times10^{10}$ M$_\odot$] is comparable with the total ionized gas mass
responsible for the diffuse nebular emission. Our observations place limits on
the molecular gas emission in the nebulae: The molecular gas surface density is
$\Sigma_{\rm H2}<12-25$ M$_\odot$ pc$^{-2}$ for the Slug nebula and
$\Sigma_{\rm H2}<34-68$ M$_\odot$ pc$^{-2}$ for the Jackpot nebula. These are
consistent with the expected molecular gas surface densities, as predicted via
photoionization models of the rest-frame UV line emission in the nebulae, and
via Ly$\alpha$ absorption in the Jackpot nebula. Compared to other radio--loud
quasars at $z>1$, and high-redshift radio--loud galaxies, we do not find any
strong trends relating the molecular gas reservoirs, the radio power, and the
Ly$\alpha$ luminosities of these systems. The significant step in sensitivity
required to achieve a detection of the molecular gas from the nebulae, if
present, will require a substantial time investment with JVLA, NOEMA, or ALMA.

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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-ex
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The categories of this paper are: eess
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The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-lat
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The categories of this paper are: q-fin
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The categories of this paper are: cs
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The categories of this paper are: quant-ph
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The categories of this paper are: math-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: stat
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The categories of this paper are: adap-org
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The categories of this paper are: gr-qc