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

Arnouts, S. and Le Floc'h, E. and Chevallard, J. and Johnson, B. D. and Ilbert, O. and Treyer, M. and Aussel, H. and Capak, P. and Sanders, D. B. and Scoville, N. and McCracken, H. J. and Milliard, B. and Pozzetti, L. and Salvato, M. (2013) Encoding of the infrared excess in the NUVrK color diagram for star-forming galaxies. Astronomy and Astrophysics, 558 . Art. No. A67. ISSN 0004-6361. doi:10.1051/0004-6361/201321768.

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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⟩ = ⟨ L_(IR)/L_(UV)⟩ 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, L_(IR), 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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Ilbert, O.0000-0002-7303-4397
Aussel, H.0000-0002-1371-5705
Capak, P.0000-0003-3578-6843
Sanders, D. B.0000-0002-1233-9998
Scoville, N.0000-0002-0438-3323
McCracken, H. J.0000-0002-9489-7765
Salvato, M.0000-0001-7116-9303
Alternate Title:Encoding the infrared excess (IRX) in the NUVrK color diagram for star-forming galaxies
Additional Information:© 2013 ESO. Article published by EDP Sciences. Published online 04 October 2013. Received 25 April 2013. Accepted 25 July 2013. We thank the anonymous referee for his useful comments. This work has been partially supported by the CNRS-INSU and the Progamme National de Cosmologie et Galaxies. J.C. acknowledges the support of the European Commission through the Marie Curie Initial Training Network ELIXIR under contract PITN-GA-2008-214227.
Group:COSMOS, Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Progamme National de Cosmologie et GalaxiesUNSPECIFIED
Marie Curie FellowshipPITN-GA-2008-214227
Institut national des sciences de l'Univers (INSU)UNSPECIFIED
Subject Keywords: infrared: galaxies, ultraviolet: galaxies, galaxies: evolution
Record Number:CaltechAUTHORS:20140108-104018487
Persistent URL:
Official Citation:Encoding of the infrared excess in the NUVrK color diagram for star-forming galaxies S. Arnouts, E. Le Floc’h, J. Chevallard, B. D. Johnson, O. Ilbert, M. Treyer, H. Aussel, P. Capak, D. B. Sanders, N. Scoville, H. J. McCracken, B. Milliard, L. Pozzetti and M. Salvato A&A 558 A67 (2013) DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:43263
Deposited By: Ruth Sustaita
Deposited On:08 Jan 2014 19:15
Last Modified:10 Nov 2021 16:35

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