The alma spectroscopic survey in the hubble ultra deep field: search for [CII] line and dust emission in 6 < z < 8 galaxies
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Fecha
2016-12
Profesor/a Guía
Facultad/escuela
Idioma
en
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Institute of Physics Publishing
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Licencia CC
Atribution 4.0 International (CC BY 4.0)
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https://creativecommons.org/licenses/by/4.0/deed.es
Resumen
We present a search for [C II] line and dust continuum emission from optical dropout galaxies at z > 6 using
ASPECS, our Atacama Large Millimeter submillimeter Array Spectroscopic Survey in the Hubble Ultra-deep Field
(UDF). Our observations, which cover the frequency range of 212–272 GHz, encompass approximately the range
of 6 < z < 8 for [C II] line emission and reach a limiting luminosity of L[C II] ∼ (1.6–2.5) × 108 Le. We identify
14 [C II] line emitting candidates in this redshift range with significances >4.5σ, two of which correspond to blind
detections with no optical counterparts. At this significance level, our statistical analysis shows that about 60% of
our candidates are expected to be spurious. For one of our blindly selected [C II] line candidates, we tentatively
detect the CO(6-5) line in our parallel 3 mm line scan. None of the line candidates are individually detected in the
1.2 mm continuum. A stack of all [C II] candidates results in a tentative detection with S1.2 mm = 14 ± 5 μJy. This
implies a dust-obscured star-formation rate (SFR) of (3 ± 1) Me yr−1
. We find that the two highest-SFR objects
have candidate [C II] lines with luminosities that are consistent with the low-redshift L[C II] versus SFR relation. The
other candidates have significantly higher [C II] luminosities than expected from their UV-based SFR. At the
current sensitivity, it is unclear whether the majority of these sources are intrinsically bright [C II] emitters, or
spurious sources. If only one of our line candidates was real (a scenario greatly favored by our statistical analysis),
we find a source density for [C II] emitters at 6 < z < 8 that is significantly higher than predicted by current
models and some extrapolations from galaxies in the local universe.
Notas
Indexación: Scopus
Palabras clave
Galaxies: Evolution, Galaxies: High-Redshift, Galaxies: ISM, Galaxies: Star Formation, Instrumentation: Interferometers, Submillimeter: Galaxies
Citación
Astrophysical Journal. Open Access. Volume 833, Issue 1. 10 December 2016. Article number 71
DOI
10.3847/1538-4357/833/1/71