ALMA observations of atomic carbon in z ∼ 4 dusty star-forming galaxies
Abstract
We present Atacama Large Millimeter Array [C i](1 − 0) (rest frequency 492 GHz) observations for a sample of 13 strongly lensed dusty star-forming galaxies (DSFGs) originally discovered at 1.4 mm in a blank-field survey by the South Pole Telescope (SPT). We compare these new data with available [Ci] observations from the literature, allowing a study of the interstellar medium (ISM) properties of ∼30 extreme DSFGs spanning a redshift range 2 < z < 5. Using the [Ci] line as a tracer of the molecular ISM, we find a mean molecular gas mass for SPT-DSFGs of 6.6 × 10^(10) M_⊙. This is in tension with gas masses derived via low-J^(12)CO and dust masses; bringing the estimates into accordance requires either (a) an elevated CO-to-H2 conversion factor for our sample of αCO ∼ 2.5 and a gas-to-dust ratio ∼200, or (b) an high carbon abundance X_(CI) ∼ 7 × 10^(−5). Using observations of a range of additional atomic and molecular lines (including [Ci], [Cii]and multiple transitions of CO), we use a modern photodissociation region code (3d-pdr) to assess the physical conditions (including the density, UV radiation field strength and gas temperature) within the ISM of the DSFGs in our sample. We find that the ISM within our DSFGs is characterized by dense gas permeated by strong UV fields. We note that previous efforts to characterize photodissociation region regions in DSFGs may have significantly under-estimated the density of the ISM. Combined, our analysis suggests that the ISM of extreme dusty starbursts at high redshift consists of dense, carbon-rich gas not directly comparable to the ISM of starbursts in the local Universe.
Additional Information
© 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2016 December 13. Received 2016 December 13; in original form 2016 September 28. This paper makes use of the following ALMA data: ADS/JAO.ALMA #2011.0.00957.S, #2011.0.00958.S, #2012.1.00844.S and #2012.1.00994.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada) and NSC and ASIAA (Taiwan), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. This work has made use of the NASA ADS. The SPT is supported by the National Science Foundation through grant PLR-1248097, with partial support through PHY-1125897, the Kavli Foundation and the Gordon and Betty Moore Foundation grant GBMF 947. MSB is supported by STFC grants ST/M001172/1 and ST/K003119/1. We acknowledge support from the US National Science Foundation under grant No. AST-1312950. MA acknowledges partial support from FONDECYT through grant 1140099.Attached Files
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Additional details
- Eprint ID
- 77208
- Resolver ID
- CaltechAUTHORS:20170505-083153828
- NSF
- PLR-1248097
- NSF
- PHY-1125897
- Gordon and Betty Moore Foundation
- GBMF 947
- Science and Technology Facilities Council (STFC)
- ST/M001172/1
- Science and Technology Facilities Council (STFC)
- ST/K003119/1
- NSF
- AST-1312950
- Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)
- 1140099
- Created
-
2017-05-05Created from EPrint's datestamp field
- Updated
-
2021-11-15Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)