SIMBAD references

2012A&A...548A..22M - Astronomy and Astrophysics, volume 548A, 22-22 (2012/12-1)

Dust temperature and CO -> H2 conversion factor variations in the SFR-M* plane.

MAGNELLI B., SAINTONGE A., LUTZ D., TACCONI L.J., BERTA S., BOURNAUD F., CHARMANDARIS V., DANNERBAUER H., ELBAZ D., FOERSTER-SCHREIBER N.M., GRACIA-CARPIO J., IVISON R., MAIOLINO R., NORDON R., POPESSO P., RODIGHIERO G., SANTINI P. and WUYTS S.

Abstract (from CDS):

Deep Herschel PACS/SPIRE imaging and 12CO(2-1) line luminosities from the IRAM Plateau de Bure Interferometer are combined for a sample of 17 galaxies at z>1 from the GOODS-N field. The sample includes galaxies both on and above the main sequence (MS) traced by star-forming galaxies in the SFR-M* plane. The far-infrared data are used to derive dust masses, Mdust, following the Draine & Li (2007ApJ...657..810D) models. Combined with an empirical prescription for the dependence of the gas-to-dust ratio on metallicity (δGDR0)), the CO luminosities and Mdust values are used to derive for each galaxy the CO-to-H2 conversion factor, αCO. Like in the local Universe, the value of αCO is a factor of ∼5 smaller in starbursts compared to normal star-forming galaxies (SFGs). We additionally uncover a relation between αCO and dust temperature (Tdust; αCO decreasing with increasing Tdust) as obtained from modified blackbody fits to the far-infrared data. While the absolute normalization of the αCO(Tdust) relation is uncertain, the global trend is robust against possible systematic biases in the determination of Mdust, δGDR0) or metallicity. Although we cannot formally distinguish between a step and a smooth evolution of αCO with the dust temperature, we can unambiguously conclude that in galaxies of near-solar metallicity, a critical value of Tdust=30K can be used to determine whether the appropriate αCO is closer to the ``starburst'' value (1.0M/(K.km/s/pc2), when Tdust>30K) or closer to the Galactic value (4.35M/(K.km/s/pc2), when Tdust<30K). This indicator has the great advantage of being less subjective than visual morphological classifications of mergers/SFGs, which can be difficult at high z because of the clumpy nature of SFGs. Using Tdust to select the appropriate αCO is also more indicative of ISM conditions than a fixed LIR criterion. In the absence of far-infrared data, the offset of a galaxy from the star formation main sequence (i.e., Δlog(SSFR)MS=log[SSFR(galaxy)/SSFRMS(M*,z)]) can be used to identify galaxies requiring the use of an αCO conversion factor lower than the Galactic value (i.e., when Δlog(SSFR)MS>0.3dex).

Abstract Copyright:

Journal keyword(s): galaxies: evolution - infrared: galaxies - galaxies: starburst

Nomenclature: Table 1: [MSL2012] PEP JHHMMSS+DDMMSS N=9

CDS comments: HDF 242 and HDF 169 are respectively NAME SMM J123707.2+621408 and NAME SMM J123635+621237 in Simbad.

Simbad objects: 22

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2021.06.19-20:16:52

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