IR and UV Galaxies at z = 0.6: Evolution of Dust Attenuation and Stellar Mass as Revealed by SWIRE and GALEX

December 2007 • 2007ApJS..173..432X

Authors • Xu, C. Kevin • Shupe, David • Buat, Veronique • Rowan-Robinson, Michael • Babbedge, Thomas • Iglesias-Páramo, Jorge • Takeuchi, Tsutomu T. • Barlow, Tom A. • Conrow, Tim • Fang, Fan • Forster, Karl • Friedman, Peter G. • Gonzales-Solares, Eduardo • Lonsdale, Carol • Martin, D. Christopher • Morrissey, Patrick • Neff, Susan G. • Schiminovich, David • Seibert, Mark • Small, Todd • Smith, Gene • Surace, Jason • Wyder, Ted K.

Abstract • We study dust attenuation and stellar mass of z~0.6 star-forming galaxies using new SWIRE observations in IR and GALEX observations in UV. Two samples are selected from the SWIRE and GALEX source catalogs in the SWIRE/GALEX field ELAIS-N1-00 (Ω=0.8 deg²). The UV-selected sample has 600 galaxies with photometric redshift (hereafter photo-z) 0.5<=z<=0.7 and NUV<=23.5 (corresponding to L_FUV>=10^9.6 L_solar). The IR-selected sample contains 430 galaxies with f_24μm>=0.2 mJy (L_dust>=10^10.8 L_solar) in the same photo-z range. It is found that the mean L_dust/L_FUV ratios of the z=0.6 UV galaxies are consistent with that of their z=0 counterparts of the same L_FUV. For IR galaxies, the mean L_dust/L_FUV ratios of the z=0.6 LIRGs (L_dust~10¹¹ L_solar) are about a factor of 2 lower than local LIRGs, whereas z=0.6 ULIRGs (L_dust~10¹² L_solar) have the same mean L_dust/L_FUV ratios as their local counterparts. This is consistent with the hypothesis that the dominant component of LIRG population has changed from large, gas-rich spirals at z>0.5 to major mergers at z=0. The stellar mass of z=0.6 UV galaxies of L_FUV<=10^10.2 L_solar is about a factor of 2 less than their local counterparts of the same luminosity, indicating growth of these galaxies. The mass of z=0.6 UV luminous galaxies (UVLGs: L_FUV>10^10.2 L_solar) and IR-selected galaxies, which are nearly exclusively LIRGs and ULIRGs, is the same as their local counterparts.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2007ApJS..173..432X
• PREPRINT http://arxiv.org/abs/astro-ph/0701737
• DATA https://irsa.ipac.caltech.edu/bibdata/2007/X/2007ApJS..173..432X.html
• ELECTR https://doi.org/10.1086%2F516641
• SPIRES http://inspirehep.net/search?p=find+eprint+astro-ph/0701737