The ALPINE-ALMA [C II] Survey: [C II] 158 μm Emission Line Luminosity Functions at z ∼ 4-6
Journal
Date Issued
2020
Author(s)
Yan, Lin
•
Sajina, A.
•
Loiacono, F.
•
Lagache, G.
•
Béthermin, M.
•
Faisst, A.
•
Ginolfi, M.
•
Fèvre, O. Le
•
•
Capak, P. L.
•
Cassata, P.
•
Schaerer, D.
•
Silverman, J. D.
•
•
Dessauges-Zavadsky, M.
•
Cimatti, A.
•
Hathi, N. P.
•
Lemaux, B. C.
•
Ibar, E.
•
Jones, G. C.
•
Koekemoer, Anton M.
•
Oesch, P. A.
•
Talia, M.
•
Pozzi, F.
•
Riechers, D. A.
•
Tasca, L. A. M.
•
Toft, Sune
•
•
•
Zamorani, G.
•
Abstract
We present the [C II] 158 μm line luminosity functions (LFs) at z ∼ 4-6 using the ALMA observations of 118 sources, which are selected to have UV luminosity M1500Å < -20.2 and optical spectroscopic redshifts in COSMOS and ECDF-S. Of the 118 targets, 75 have significant [C II] detections and 43 are upper limits. This is by far the largest sample of [C II] detections, which allows us to set constraints on the volume density of [C II] emitters at z ∼ 4-6. But because this is a UV-selected sample, we are missing [C II]-bright but UV-faint sources, making our constraints strict lower limits. Our derived LFs are statistically consistent with the z ∼ 0 [C II] LF at 108.25-109.75L⊙. We compare our results with the upper limits of the [C II] LF derived from serendipitous sources in the ALPINE maps. We also infer the [C II] LFs based on published far-IR and CO LFs at z ∼ 4-6. Combining our robust lower limits with these additional estimates, we set further constraints on the true number density of [C II] emitters at z ∼ 4-6. These additional LF estimates are largely above our LF at L[CII] > 109L⊙, suggesting that UV-faint but [C II]-bright sources likely make significant contributions to the [C II] emitter volume density. When we include all the LF estimates, we find that available model predictions underestimate the number densities of [C II] emitters at z ∼ 4-6. Finally, we set a constraint on the molecular gas mass density at z ∼ 4-6, with ρmol ∼ (2-7) × 107M⊙ Mpc-3. This is broadly consistent with previous studies.
Volume
905
Issue
2
Start page
147
Issn Identifier
0004-637X
Ads BibCode
2020ApJ...905..147Y
Rights
open.access
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