Encoding of the infrared excess in the NUVrK color diagram for star-forming galaxies - Archive ouverte HAL Access content directly
Journal Articles Astronomy and Astrophysics - A&A Year : 2013

Encoding of the infrared excess in the NUVrK color diagram for star-forming galaxies

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O. Ilbert
  • Function : Author
M. Treyer
  • Function : Author
H. Aussel
P. Capak
D. B. Sanders
  • Function : Author
N. Scoville
  • Function : Author
H. J. Mccracken
  • Function : Author
B. Milliard
  • Function : Author
L. Pozzetti
  • Function : Author
M. Salvato
  • Function : Author

Abstract

We present an empirical method of assessing the star formation rate (SFR) of star-forming galaxies based on their locations in the rest-frame color–color diagram (NUV − r) vs. (r − K). By using the Spitzer 24  μm sample in the COSMOS field (~16 400 galaxies with 0.2 ≤ z ≤ 1.3) and a local GALEX-SDSS-SWIRE sample (~700 galaxies with z ≤ 0.2), we show that the mean infrared excess ⟨IRX⟩ = ⟨ LIR/LUV ⟩ can be described by a single vector, NRK , that combines the two colors. The calibration between ⟨IRX⟩ and NRK allows us to recover the IR luminosity, LIR, with an accuracy of σ ~ 0.21 for the COSMOS sample and 0.27 dex for the local one. The SFRs derived with this method agree with the ones based on the observed (UV+IR) luminosities and on the spectral energy distribution (SED) fitting for the vast majority (~85%) of the star-forming population. Thanks to a library of model galaxy SEDs with realistic prescriptions for the star formation history, we show that we need to include a two-component dust model (i.e., birth clouds and diffuse ISM) and a full distribution of galaxy inclinations in order to reproduce the behavior of the ⟨IRX⟩ stripes in the NUVrK diagram. In conclusion, the NRK method, based only on the rest-frame UV/optical colors available in most of the extragalactic fields, offers a simple alternative of assessing the SFR of star-forming galaxies in the absence of far-IR or spectral diagnostic observations.
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Dates and versions

cea-01135438 , version 1 (25-03-2015)

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Cite

S. Arnouts, E. Le Floc’h, J. Chevallard, B. D. Johnson, O. Ilbert, et al.. Encoding of the infrared excess in the NUVrK color diagram for star-forming galaxies. Astronomy and Astrophysics - A&A, 2013, 558, pp.A67. ⟨10.1051/0004-6361/201321768⟩. ⟨cea-01135438⟩
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