Mid- and Far-infrared Luminosity Functions and Galaxy Evolution from Multiwavelength Spitzer Observations up to z~2.5
Abstract
[Abridged]We exploit a large homogeneous dataset to derive a self-consistent picture of IR emission based on the time-dependent 24, 15, 12 and 8micron monochromatic and bolometric IR luminosity functions (LF) over the 0<z<2.5 redshift range. Our analysis is based on the combination of data from deep Spitzer surveys in the VVDS-SWIRE and GOODS areas. To our limiting flux of S(24)=400microJy our derived sample in VVDS-SWIRE includes 1494 sources, and 666 and 904 sources brighter than S(24)=80microJy are catalogued in GOODS-S and GOODS-N, respectively, for a total area of ~0.9 square degs. We obtain reliable optical identifications and redshifts, providing us a rich and robust dataset for our luminosity function determination. Based on the multi-wavelength information available, we constrain the LFs at 8, 12, 15 and 24micron. We also extrapolate total IR luminosities from our best-fit to the observed SEDs of each source, and use this to derive the bolometric LF and comoving volume emissivity up to z~2.5. In the 0<z<1 interval, the bolometric IR luminosity density evolves as (1+z)^3.8+/-0.4. Although more uncertain at higher-z, our results show a flattening of the IR luminosity density at z>1. The mean redshift of the peak in the source number density shifts with luminosity: the brighest IR galaxies appear to be forming stars earlier in cosmic time (z>1.5), while the less luminous ones keep doing it at more recent epochs (z~1 for L(IR)<10^11L_sun). Our results suggest a rapid increase of the galaxy IR comoving volume emissivity back to z~1 and a constant average emissivity at z>1. We also seem to find a difference in the evolution rate of the source number densities as a function of luminosity, a downsizing evolutionary pattern similar to that reported from other samples of cosmic sources.
Keywords
Cite
@article{arxiv.0910.5649,
title = {Mid- and Far-infrared Luminosity Functions and Galaxy Evolution from Multiwavelength Spitzer Observations up to z~2.5},
author = {G. Rodighiero and M. Vaccari and A. Franceschini and L. Tresse and O. Le Fevre and V. Le Brun and C. Mancini and I. Matute and A. Cimatti and L. Marchetti and O. Ilbert and S. Arnouts and M. Bolzonella and E. Zucca and S. Bardelli and C. J. Lonsdale and D. Shupe and J. Surace and M. Rowan-Robinson and B. Garilli and G. Zamorani and L. Pozzetti and M. Bondi and S. de la Torre and D. Vergani and P. Santini and A. Grazian and A . Fontana},
journal= {arXiv preprint arXiv:0910.5649},
year = {2015}
}
Comments
Accepted for pubblicantion in Astronomy and Astrophysics