Regulating Star Formation in Nearby Dusty Galaxies: Low Photoelectric Efficiencies in the Most Compact Systems
Abstract
Star formation in galaxies is regulated by heating and cooling in the interstellar medium (ISM). In particular, the processing of molecular gas into stars will depend strongly on the ratio of gas heating to gas cooling in the neutral gas around sites of recent star formation. In this work, we combine mid-infrared (mid-IR) observations of polycyclic aromatic hydrocarbons (PAHs), the dominant heating mechanism of gas in the ISM, with [C ii], [O i], and [Si ii] fine-structure emission, the strongest cooling channels in dense, neutral gas. The ratio of IR cooling line emission to PAH emission measures the photoelectric efficiency, a property of the ISM which dictates how much energy carried by ultraviolet photons gets transferred into the gas. We find that star-forming, IR-luminous galaxies in the Great Observatories All-Sky LIRG Survey with high IR surface densities have low photoelectric efficiencies. These systems also have, on average, higher ratios of radiation field strength to gas densities, and larger average dust grain size distributions. The data support a scenario in which the most compact galaxies have more young star-forming regions per unit area that exhibit less efficient gas heating. These conditions may be more common at high z, and may help explain the higher star formation rates at cosmic noon. We make predictions on how this can be investigated with the James Webb Space Telescope.
Additional Information
© 2021 The American Astronomical Society. Received 2020 October 12; revised 2020 December 17; accepted 2020 December 24; published 2021 February 26. We thank the referee for the thoughtful comments and recommendations. J.M. thanks S. Linden for the constructive feedback on the paper. J.M. was supported by the IPAC Visiting Graduate Fellowship. A.S.E. and Y.S. were supported by NSF grant AST 1816838. H.I. acknowledges support from JSPS KAKENHI grant No. JP19K23462. This work is based on observations made with the Herschel Space Observatory, a European Space Agency (ESA) Cornerstone Mission with science instruments provided by European-led Principal Investigator consortia and significant participation from NASA. The Spitzer Space Telescope is operated by the Jet Propulsion Laboratory, California Institute of Technology, under NASA contract 1407. This research is based on observations with AKARI, a JAXA project with the participation of ESA. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration, and of NASAs Astrophysics Data System (ADS) abstract service. This research has made use of the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics Space Administration.Attached Files
Published - McKinney_2021_ApJ_908_238.pdf
Accepted Version - 2101.01182.pdf
Files
| Name | Size | Download all |
|---|---|---|
|
md5:636ae0b40394d9999828fbbaaff1a69a
|
1.4 MB | Preview Download |
|
md5:e83b4e43cb8e8c66f2ecbd2036956027
|
1.3 MB | Preview Download |
Additional details
- Eprint ID
- 108247
- Resolver ID
- CaltechAUTHORS:20210301-120030955
- Infrared Processing and Analysis Center (IPAC)
- AST-1816838
- NSF
- JP19K23462
- Japan Society for the Promotion of Science (JSPS)
- 1407
- NASA/JPL/Caltech
- Created
-
2021-03-01Created from EPrint's datestamp field
- Updated
-
2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)