We present (CO)-C-12(J = 1-0) line observations of 22 low-luminosity spiral galaxies in the Virgo cluster. These data, together with 244 others available in the literature, allow us to build a large sample that we use to study the molecular gas properties of galaxies spanning a large range of morphological types and luminosities and belonging to different environments (clusters-field). The molecular gas content of the target galaxies is estimated using a luminosity-dependent X=N(H-2)/I(CO) conversion factor that has been calibrated on a sample of nearby galaxies. X spans from similar to10(20) mol cm(-2) (K km s(-1))(-1) in giant spirals to similar to10(21) mol cm(-2) (K km s(-1))(-1) in dwarf irregulars. The value of the X conversion factor is found consistent with a value derived independently from dust masses estimated from FIR fluxes, with a metallicity-dependent dust to gas ratio. The relationships between X and the UV radiation field (as traced by the Halpha + [NII]EW), the metallicity and the H band luminosity are analysed. We show that the molecular gas contained in molecular clouds or complexes is of the order of 15% of the total gas on average whatever the luminosity or the Hubble type of the galaxies. We discuss the relation between the star formation rate and the molecular gas content and estimate the average star formation efficiency of late-type galaxies.

Boselli, A., Lequeux, J., Gavazzi, G. (2002). Molecular gas in normal late-type galaxies. ASTRONOMY & ASTROPHYSICS, 384(1), 33-47 [10.1051/0004-6361:20011747].

Molecular gas in normal late-type galaxies

GAVAZZI, GIUSEPPE
2002

Abstract

We present (CO)-C-12(J = 1-0) line observations of 22 low-luminosity spiral galaxies in the Virgo cluster. These data, together with 244 others available in the literature, allow us to build a large sample that we use to study the molecular gas properties of galaxies spanning a large range of morphological types and luminosities and belonging to different environments (clusters-field). The molecular gas content of the target galaxies is estimated using a luminosity-dependent X=N(H-2)/I(CO) conversion factor that has been calibrated on a sample of nearby galaxies. X spans from similar to10(20) mol cm(-2) (K km s(-1))(-1) in giant spirals to similar to10(21) mol cm(-2) (K km s(-1))(-1) in dwarf irregulars. The value of the X conversion factor is found consistent with a value derived independently from dust masses estimated from FIR fluxes, with a metallicity-dependent dust to gas ratio. The relationships between X and the UV radiation field (as traced by the Halpha + [NII]EW), the metallicity and the H band luminosity are analysed. We show that the molecular gas contained in molecular clouds or complexes is of the order of 15% of the total gas on average whatever the luminosity or the Hubble type of the galaxies. We discuss the relation between the star formation rate and the molecular gas content and estimate the average star formation efficiency of late-type galaxies.
Articolo in rivista - Articolo scientifico
Galaxies; general; spiral; ISM; galaxies; intergalactic medium; radio lines; galaxies
English
2002
384
1
33
47
none
Boselli, A., Lequeux, J., Gavazzi, G. (2002). Molecular gas in normal late-type galaxies. ASTRONOMY & ASTROPHYSICS, 384(1), 33-47 [10.1051/0004-6361:20011747].
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/22496
Citazioni
  • Scopus 177
  • ???jsp.display-item.citation.isi??? 180
Social impact