Star formation rates from [C II] 158 µm and mid-infrared emission lines for starbursts and active galactic nuclei.
SARGSYAN L., SAMSONYAN A., LEBOUTEILLER V., WEEDMAN D., BARRY D., BERNARD-SALAS J., HOUCK J. and SPOON H.
Abstract (from CDS):
A summary is presented for 130 galaxies observed with the Herschel Photodetector Array Camera and Spectrometer instrument to measure fluxes for the [C II] 158 µm emission line. Sources cover a wide range of active galactic nucleus to starburst classifications, as derived from polycyclic aromatic hydrocarbon strength measured with the Spitzer Infrared Spectrograph. Redshifts from [C II] and line to continuum strengths (equivalent width (EW) of [C II]) are given for the full sample, which includes 18 new [C II] flux measures. Calibration of L([C II)]) as a star formation rate (SFR) indicator is determined by comparing [C II] luminosities with mid-infrared [Ne II] and [Ne III] emission line luminosities; this gives the same result as determining SFR using bolometric luminosities of reradiating dust from starbursts: log SFR = log L([C II)]) - 7.0, for SFR in M☉/yr and L([C II]) in L☉. We conclude that L([C II]) can be used to measure SFR in any source to a precision of ∼50%, even if total source luminosities are dominated by an active galactic nucleus (AGN) component. The line to continuum ratio at 158 µm, EW([C II]), is not significantly greater for starbursts (median EW([C II]) = 1.0 µm) compared to composites and AGNs (median EW([C II]) = 0.7 µm), showing that the far-infrared continuum at 158 µm scales with [C II] regardless of classification. This indicates that the continuum at 158 µm also arises primarily from the starburst component within any source, giving log SFR = log νLν(158 µm) - 42.8 for SFR in M☉/yr and νLν(158 µm) in erg/s.
galaxies: active - galaxies: distances and redshifts - galaxies: starburst - infrared: galaxies