Deriving a multivariate alpha(CO) conversion function using the [C II]/CO (1-0) ratio and its application to molecular gas scaling relations

G. Accurso, A. Saintonge, B. Catinella, L. Cortese, R. Dave, S. H. Dunsheath, R. Genzel, J. Gracia-Carpio, T. M. Heckman, Jimmy, C. Kramer, Cheng Li, K. Lutz, D. Schiminovich, K. Schuster, A. Sternberg, E. Sturm, L. J. Tacconi, K. V. Tran, J. Wang

Research output: Contribution to journalArticle

Abstract

We present Herschel PACS observations of the [C II] 158 mu m emission line in a sample of 24 intermediate mass (9 <logM*/M circle dot <10) and low metallicity (0.4 <Z/Z circle dot <1.0) galaxies from the xCOLD GASS survey. In combination with IRAM CO(1-0) measurements, we establish scaling relations between integrated and molecular region L[C II]/LCO(1-0) ratios as a function of integrated galaxy properties. A Bayesian analysis reveals that only two parameters, metallicity and offset from the main sequence, Delta(MS), are needed to quantify variations in the luminosity ratio; metallicity describes the total dust content available to shield CO from UV radiation, while Delta (MS) describes the strength of this radiation field. We connect the L[C II]/LCO(1-0) ratio to the CO-to-H-2 conversion factor and find a multivariate conversion function, which can be used up to z similar to 2.5. This function depends primarily on metallicity, with a second-order dependence on Delta (MS). We apply this to the full xCOLD GASS and PHIBSS1 surveys and investigate molecular gas scaling relations. We find a flattening of the relation between gas mass fraction and stellar mass at logM* <10.0. While the molecular gas depletion time varies with sSFR, it is mostly independent of mass, indicating that the low L-CO/SFR ratios long observed in low-mass galaxies are entirely due to photodissociation of CO and not to an enhanced star formation efficiency.

LanguageEnglish
Pages4750-4766
Number of pages17
JournalMonthly Notices of the Royal Astronomical Society
Volume470
Issue number4
DOIs
StatePublished - Oct 2017

Cite this

Accurso, G. ; Saintonge, A. ; Catinella, B. ; Cortese, L. ; Dave, R. ; Dunsheath, S. H. ; Genzel, R. ; Gracia-Carpio, J. ; Heckman, T. M. ; Jimmy ; Kramer, C. ; Li, Cheng ; Lutz, K. ; Schiminovich, D. ; Schuster, K. ; Sternberg, A. ; Sturm, E. ; Tacconi, L. J. ; Tran, K. V. ; Wang, J./ Deriving a multivariate alpha(CO) conversion function using the [C II]/CO (1-0) ratio and its application to molecular gas scaling relations. In: Monthly Notices of the Royal Astronomical Society. 2017 ; Vol. 470, No. 4. pp. 4750-4766
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Accurso, G, Saintonge, A, Catinella, B, Cortese, L, Dave, R, Dunsheath, SH, Genzel, R, Gracia-Carpio, J, Heckman, TM, Jimmy, Kramer, C, Li, C, Lutz, K, Schiminovich, D, Schuster, K, Sternberg, A, Sturm, E, Tacconi, LJ, Tran, KV & Wang, J 2017, 'Deriving a multivariate alpha(CO) conversion function using the [C II]/CO (1-0) ratio and its application to molecular gas scaling relations' Monthly Notices of the Royal Astronomical Society, vol 470, no. 4, pp. 4750-4766. DOI: 10.1093/mnras/stx1556

Deriving a multivariate alpha(CO) conversion function using the [C II]/CO (1-0) ratio and its application to molecular gas scaling relations. / Accurso, G.; Saintonge, A.; Catinella, B.; Cortese, L.; Dave, R.; Dunsheath, S. H.; Genzel, R.; Gracia-Carpio, J.; Heckman, T. M.; Jimmy; Kramer, C.; Li, Cheng; Lutz, K.; Schiminovich, D.; Schuster, K.; Sternberg, A.; Sturm, E.; Tacconi, L. J.; Tran, K. V.; Wang, J.

In: Monthly Notices of the Royal Astronomical Society, Vol. 470, No. 4, 10.2017, p. 4750-4766.

Research output: Contribution to journalArticle

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T1 - Deriving a multivariate alpha(CO) conversion function using the [C II]/CO (1-0) ratio and its application to molecular gas scaling relations

AU - Accurso,G.

AU - Saintonge,A.

AU - Catinella,B.

AU - Cortese,L.

AU - Dave,R.

AU - Dunsheath,S. H.

AU - Genzel,R.

AU - Gracia-Carpio,J.

AU - Heckman,T. M.

AU - Jimmy,null

AU - Kramer,C.

AU - Li,Cheng

AU - Lutz,K.

AU - Schiminovich,D.

AU - Schuster,K.

AU - Sternberg,A.

AU - Sturm,E.

AU - Tacconi,L. J.

AU - Tran,K. V.

AU - Wang,J.

PY - 2017/10

Y1 - 2017/10

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AB - We present Herschel PACS observations of the [C II] 158 mu m emission line in a sample of 24 intermediate mass (9

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KW - galaxies: fundamental parameters

KW - galaxies: ISM

KW - radio lines: galaxies

KW - STAR-FORMING GALAXIES

KW - DIGITAL SKY SURVEY

KW - MASS-METALLICITY RELATION

KW - ARECIBO SDSS SURVEY

KW - GAMMA-RAY EMISSION

KW - IRAM LEGACY SURVEY

KW - NEARBY GALAXIES

KW - PHOTODISSOCIATION REGIONS

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KW - INTERSTELLAR-MEDIUM

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SP - 4750

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