Schrodinger’s Galaxy Candidate: Puzzlingly Luminous at $zapprox17$, or Dusty/Quenched at $zapprox5$?. (arXiv:2208.02794v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Naidu_R/0/1/0/all/0/1">Rohan P. Naidu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Oesch_P/0/1/0/all/0/1">Pascal A. Oesch</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Setton_D/0/1/0/all/0/1">David J. Setton</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matthee_J/0/1/0/all/0/1">Jorryt Matthee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Conroy_C/0/1/0/all/0/1">Charlie Conroy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Johnson_B/0/1/0/all/0/1">Benjamin D. Johnson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Weaver_J/0/1/0/all/0/1">John R. Weaver</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bouwens_R/0/1/0/all/0/1">Rychard J. Bouwens</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brammer_G/0/1/0/all/0/1">Gabriel B. Brammer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dayal_P/0/1/0/all/0/1">Pratika Dayal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Illingworth_G/0/1/0/all/0/1">Garth D. Illingworth</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barrufet_L/0/1/0/all/0/1">Laia Barrufet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Belli_S/0/1/0/all/0/1">Sirio Belli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bezanson_R/0/1/0/all/0/1">Rachel Bezanson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bose_S/0/1/0/all/0/1">Sownak Bose</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Heintz_K/0/1/0/all/0/1">Kasper E. Heintz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leja_J/0/1/0/all/0/1">Joel Leja</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leonova_E/0/1/0/all/0/1">Ecaterina Leonova</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marques_Chaves_R/0/1/0/all/0/1">Rui Marques-Chaves</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stefanon_M/0/1/0/all/0/1">Mauro Stefanon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Toft_S/0/1/0/all/0/1">Sune Toft</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wel_A/0/1/0/all/0/1">Arjen van der Wel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dokkum_P/0/1/0/all/0/1">Pieter van Dokkum</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Weibel_A/0/1/0/all/0/1">Andrea Weibel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Whitaker_K/0/1/0/all/0/1">Katherine E. Whitaker</a>

$JWST$’s first glimpse of the $z>10$ Universe has yielded a surprising
abundance of luminous galaxy candidates. Here we present the most extreme of
these systems: CEERS-1749. Based on $0.6-5mu$m photometry, this strikingly
luminous ($approx$26 mag) galaxy appears to lie at $zapprox17$. This would
make it an $M_{rm{UV}}approx-22$,
$M_{rm{star}}approx5times10^{9}M_{rm{odot}}$ system that formed a mere
$sim220$ Myrs after the Big Bang. The implied number density of this galaxy
and its analogues challenges virtually every early galaxy evolution model that
assumes $Lambda$CDM cosmology. However, there is strong environmental evidence
supporting a secondary redshift solution of $zapprox5$: all three of the
galaxy’s nearest neighbors at $<2.5$” have photometric redshifts of
$zapprox5$. Further, we show that CEERS-1749 may lie in a $zapprox5$
protocluster that is $gtrsim5times$ overdense compared to the field. Intense
line emission at $zapprox5$ from a quiescent galaxy harboring ionized gas, or
from a dusty starburst, may provide satisfactory explanations for CEERS-1749’s
photometry. The emission lines at $zapprox5$ conspire to boost the $>2mu$m
photometry, producing an apparent blue slope as well as a strong break in the
SED. Such a perfectly disguised contaminant is possible only in a narrow
redshift window ($Delta zlesssim0.1$), implying that the permitted volume for
such interlopers may not be a major concern for $z>10$ searches, particularly
when medium-bands are deployed. If CEERS-1749 is confirmed to lie at
$zapprox5$, it will be the highest-redshift quiescent galaxy, or one of the
lowest mass dusty galaxies of the early Universe detected to-date. Both
redshift solutions of this intriguing galaxy hold the potential to challenge
existing models of early galaxy evolution, making spectroscopic follow-up of
this source critical.

$JWST$’s first glimpse of the $z>10$ Universe has yielded a surprising
abundance of luminous galaxy candidates. Here we present the most extreme of
these systems: CEERS-1749. Based on $0.6-5mu$m photometry, this strikingly
luminous ($approx$26 mag) galaxy appears to lie at $zapprox17$. This would
make it an $M_{rm{UV}}approx-22$,
$M_{rm{star}}approx5times10^{9}M_{rm{odot}}$ system that formed a mere
$sim220$ Myrs after the Big Bang. The implied number density of this galaxy
and its analogues challenges virtually every early galaxy evolution model that
assumes $Lambda$CDM cosmology. However, there is strong environmental evidence
supporting a secondary redshift solution of $zapprox5$: all three of the
galaxy’s nearest neighbors at $<2.5$” have photometric redshifts of
$zapprox5$. Further, we show that CEERS-1749 may lie in a $zapprox5$
protocluster that is $gtrsim5times$ overdense compared to the field. Intense
line emission at $zapprox5$ from a quiescent galaxy harboring ionized gas, or
from a dusty starburst, may provide satisfactory explanations for CEERS-1749’s
photometry. The emission lines at $zapprox5$ conspire to boost the $>2mu$m
photometry, producing an apparent blue slope as well as a strong break in the
SED. Such a perfectly disguised contaminant is possible only in a narrow
redshift window ($Delta zlesssim0.1$), implying that the permitted volume for
such interlopers may not be a major concern for $z>10$ searches, particularly
when medium-bands are deployed. If CEERS-1749 is confirmed to lie at
$zapprox5$, it will be the highest-redshift quiescent galaxy, or one of the
lowest mass dusty galaxies of the early Universe detected to-date. Both
redshift solutions of this intriguing galaxy hold the potential to challenge
existing models of early galaxy evolution, making spectroscopic follow-up of
this source critical.

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