Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Extremely Massive Quiescent Galaxy at $z=3.493$: Evidence of
  Insufficiently Rapid Quenching Mechanisms in Theoretical Models   We present spectra of the most massive quiescent galaxy yet discovered at
$z>3$, spectroscopically confirmed via the detection of Balmer absorption
features in the $H-$ and $K-$bands of Keck/MOSFIRE. The spectra confirm a
galaxy with no significant ongoing star formation, consistent with the lack of
rest-frame UV flux and overall photometric spectral energy distribution. With a
stellar mass of $3.1^{+0.1}_{-0.2} \times 10^{11} ~\rm{M}_\odot$ at $z =
3.493$, this galaxy is nearly three times more massive than the highest
redshift spectroscopically confirmed absorption-line identified galaxy known.
The star-formation history of this quiescent galaxy implies that it formed
$>1000 ~\rm{M}_\odot$/yr for almost 0.5 Gyr beginning at $z\sim7.2$, strongly
suggestive that it is the descendant of massive dusty star-forming galaxies at
$5<z<7$ recently observed with ALMA. While galaxies with similarly extreme
stellar masses are reproduced in some simulations at early times, such a lack
of ongoing star formation is not seen there. This suggests the need for a more
rapid quenching process than is currently prescribed, challenging our current
understanding of how ultra-massive galaxies form and evolve in the early
Universe.

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The categories of this paper are: acc-phys
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The categories of this paper are: supr-con
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The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
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The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
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The categories of this paper are: chem-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-th
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The categories of this paper are: stat
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The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
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The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
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The categories of this paper are: patt-sol