The ALMA spectroscopic survey in the Hubble Ultra Deep Field: search for [C II] line and dust emission in 6 < z < 8 galaxies
- Núcleo de Astronomía, Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército 441, Santiago (Chile)
- Max-Planck Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany)
- Leiden Observatory, Leiden University, P.O. Box 9513, NL2300 RA Leiden (Netherlands)
- Astronomy Department, Yale University, New Haven, CT 06511 (United States)
- Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago (Chile)
- Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia)
- Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/Service d’Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette cedex (France)
- European Southern Observatory, Karl-Schwarzschild Strasse 2, D-85748 Garching bei München (Germany)
- Cornell University, 220 Space Sciences Building, Ithaca, NY 14853 (United States)
- Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom)
- Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany)
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 {sub [C ii]} ∼ (1.6–2.5) × 10{sup 8} L {sub ⊙}. 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 S {sub 1.2 mm} = 14 ± 5 μJy. This implies a dust-obscured star-formation rate (SFR) of (3 ± 1) M {sub ⊙} yr{sup −1}. We find that the two highest-SFR objects have candidate [C ii] lines with luminosities that are consistent with the low-redshift L {sub [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.
- OSTI ID:
- 22868352
- Journal Information:
- Astrophysical Journal, Vol. 833, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
ALMA spectroscopic survey in the Hubble Ultra Deep Field: the infrared excess of UV-selected z = 2–10 galaxies as a function of UV-continuum slope and stellar mass
A SEARCH FOR C II 158 {mu}m LINE EMISSION IN HCM 6A, A Ly{alpha} EMITTER AT z = 6.56