Silverman_2018_ApJ_867_92.pdf (2.21 MB)
The molecular gas content and fuel efficiency of starbursts at z ~ 1.6 with ALMA
Version 2 2023-06-12, 07:31
Version 1 2023-06-09, 16:04
journal contribution
posted on 2023-06-12, 07:31 authored by J D Silverman, W Rujopakarn, E Daddi, A Renzini, G Rodighiero, D Liu, A Puglisi, Mark Sargent, C Mancini, J Kartaltepe, D Kashino, A Koekemoer, N Arimoto, M Béthermin, S Jin, G Madgis, T Nagao, M Onodera, D Sanders, F ValentinoWe present an analysis of the molecular gas properties, based on CO(2 - 1) emission, of twelve starburst galaxies at z~1.6 selected by having a boost (>~4x) in their star formation rate (SFR) above the average star-forming galaxy at an equivalent stellar mass. ALMA observations are acquired of six additional galaxies than previously reported through our effort. As a result of the larger statistical sample, we significantly detect, for the first time at high-z, a systematically lower L'_CO/L_IR ratio in galaxies lying above the star-forming `main sequence' (MS). Based on an estimate of alpha_CO (i.e., the ratio of molecular gas mass to L'_CO(1-0)), we convert the observational quantities (e.g., L'_CO/L_IR) to physical units (M_gas/SFR) that represent the gas depletion time or its inverse, the star formation efficiency. We interpret the results as indicative of the star formation efficiency increasing in a continuous fashion from the MS to the starburst regime, whereas the gas fractions remain comparable to those of MS galaxies. Although, the balance between an increase in star-formation efficiency or gas fraction depends on the adopted value of alpha_CO as discussed.
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- Published
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- Published version
Journal
Astrophysical JournalISSN
0004-637XPublisher
American Astronomical SocietyExternal DOI
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2Volume
867Page range
1-12Department affiliated with
- Physics and Astronomy Publications
Research groups affiliated with
- Astronomy Centre Publications
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- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2018-11-28First Open Access (FOA) Date
2018-11-28First Compliant Deposit (FCD) Date
2018-11-27Usage metrics
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