SIMBAD references

We present deep K_s<21.5 (Vega) identifications, redshifts, and stellar masses for most of the sources composing the bulk of the 24 µm background in the GOODS/CDFS. Our identified sample consists of 747 Spitzer MIPS 24 µm objects and includes ∼94% of all the 24 µm sources in the GOODS-South field that have fluxes S_ν(24 µm)>83 µJy (the ∼80% completeness limit of the Spitzer/GTO 24 µm catalog); 36% of our galaxies have spectroscopic redshifts (mostly at z<1.5), and the remaining ones have photometric redshifts of very good quality, with a median of|dz|=|z_spec-z_phot|/(1+z_spec)=0.02. We find that MIPS 24 µm galaxies span the redshift range z∼0-4 and that a substantial fraction (28%) lie at high redshifts z≳1.5. We determine the existence of a bump in the redshift distribution at z∼1.9, indicating the presence of a significant population of galaxies with PAH emission at these redshifts. The 24 µm galaxy population ranges from sources with intermediate luminosities (10¹⁰ L_☉<L_IR<10¹¹ L_☉) and low-to-intermediate assembled stellar masses (10⁹ M_☉≲M≲10¹¹ M_☉) at z≲0.8, to massive (M≳10¹¹ M_☉) hyperluminous galaxies (L_IR>10¹² L_☉) at redshifts z∼2-3. Massive star-forming galaxies at redshifts 2≲z≲3 are characterized by very high star formation rates (SFR>500 M_☉/yr), and some of them are able to construct a mass of ~10¹⁰-10¹¹ M_☉ in a single burst lifetime (∼0.01-0.1 Gyr). At lower redshifts z≲2, massive star-forming galaxies are also present but appear to be building their stars on long timescales, either quiescently or in multiple modest burstlike episodes. At redshifts z∼1-2, the ability of the burstlike mode to produce entire galaxies in a single event is limited to some lower (M≲7x10¹⁰ M_☉) mass systems, and it is basically negligible at z≲1. Our results support a scenario in which star formation activity is differential with assembled stellar mass and redshift, and where the relative importance of the burstlike mode proceeds in a downsizing way from high to low redshifts.