SFR estimations from z = 0 to z = 0.9. A comparison of SFR calibrators for star-forming galaxies
Résumé
Context. The star formation rate (SFR) is a key ingredient for studying the formation and evolution of galaxies. Being able to obtain accurate estimations of the SFR, for a wide range of redshifts, is crucial for building and studying galaxy evolution paths over cosmic time.
Aims: Based on a statistical sample of galaxies, the aim of this paper is to constrain a set of SFR calibrators that are able to work in a large redshift range, from z = 0 to z = 0.9. Those calibrators will help to homogenize SFR estimations of star-forming galaxies and to remove any possible biases from the study of galaxy evolution.
Methods: Using the VIMOS Public Extragalactic Redshift Survey (VIPERS), we estimated a set of SFR based on photometric and spectroscopic data. We used, as estimators, photometric bands from ultraviolet (UV) to mid-infrared (mid-IR), and the spectral lines Hβ, [O II]λ3727, and [O III]λ5007. Assuming a reference SFR obtained from the spectral energy distribution reconstructed with Code Investigating GALaxy Emission (CIGALE), we estimated the reliability of each band as an SFR tracer. We used the GALEX-SDSS-WISE Legacy Catalog (GSWLC, z < 0.3) to trace the dependence of these SFR calibrators with redshift.
Results: The far and near UV (FUV and NUV, respectively), u-band and 24 μm bands, as well as LTIR, are found to be good SFR tracers up to z ∼ 0.9 with a strong dependence on the attenuation prescription used for the bluest bands (scatter of SFR of 0.26, 0.14, 0.15, 0.23, and 0.24 dex for VIPERS, and 0.25, 0.24, 0.09, 0.12, and 0.12 dex for GSWLC). The 8 μm band provides only a rough estimate of the SFR as it depends on metallicity and polycyclic aromatic hydrocarbon properties (scatter of 0.23 dex for VIPERS). We estimated the scatter of rest-frame luminosity estimations from CIGALE to be 0.26, 0.14, 0.12, 0.15, and 0.20 dex for FUV, NUV, ugriz, Ks, and 8-24 μm-LTIR. At intermediate redshift, the Hβ line is a reliable SFR tracer (scatter of 0.19 dex) and the [O II]λ3727 line gives an equally good estimation when the metallicity from the R23 parameter is taken into account (0.17 for VIPERS and 0.20 dex for GSWLC). A calibration based on [O III] retrieves the SFR only when additional information such as the metallicity or the ionization parameter of galaxies are used (0.26 for VIPERS and 0.20 dex for GSWLC), diminishing its usability as a direct SFR tracer. Based on rest-frame luminosities estimated with CIGALE, we propose our own set of calibrations from FUV, NUV, u-band, 8, 24 μm, LTIR, Hβ, [O II], and [O III].
Aims: Based on a statistical sample of galaxies, the aim of this paper is to constrain a set of SFR calibrators that are able to work in a large redshift range, from z = 0 to z = 0.9. Those calibrators will help to homogenize SFR estimations of star-forming galaxies and to remove any possible biases from the study of galaxy evolution.
Methods: Using the VIMOS Public Extragalactic Redshift Survey (VIPERS), we estimated a set of SFR based on photometric and spectroscopic data. We used, as estimators, photometric bands from ultraviolet (UV) to mid-infrared (mid-IR), and the spectral lines Hβ, [O II]λ3727, and [O III]λ5007. Assuming a reference SFR obtained from the spectral energy distribution reconstructed with Code Investigating GALaxy Emission (CIGALE), we estimated the reliability of each band as an SFR tracer. We used the GALEX-SDSS-WISE Legacy Catalog (GSWLC, z < 0.3) to trace the dependence of these SFR calibrators with redshift.
Results: The far and near UV (FUV and NUV, respectively), u-band and 24 μm bands, as well as LTIR, are found to be good SFR tracers up to z ∼ 0.9 with a strong dependence on the attenuation prescription used for the bluest bands (scatter of SFR of 0.26, 0.14, 0.15, 0.23, and 0.24 dex for VIPERS, and 0.25, 0.24, 0.09, 0.12, and 0.12 dex for GSWLC). The 8 μm band provides only a rough estimate of the SFR as it depends on metallicity and polycyclic aromatic hydrocarbon properties (scatter of 0.23 dex for VIPERS). We estimated the scatter of rest-frame luminosity estimations from CIGALE to be 0.26, 0.14, 0.12, 0.15, and 0.20 dex for FUV, NUV, ugriz, Ks, and 8-24 μm-LTIR. At intermediate redshift, the Hβ line is a reliable SFR tracer (scatter of 0.19 dex) and the [O II]λ3727 line gives an equally good estimation when the metallicity from the R23 parameter is taken into account (0.17 for VIPERS and 0.20 dex for GSWLC). A calibration based on [O III] retrieves the SFR only when additional information such as the metallicity or the ionization parameter of galaxies are used (0.26 for VIPERS and 0.20 dex for GSWLC), diminishing its usability as a direct SFR tracer. Based on rest-frame luminosities estimated with CIGALE, we propose our own set of calibrations from FUV, NUV, u-band, 8, 24 μm, LTIR, Hβ, [O II], and [O III].
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