Dissecting the cosmic infra-red background with Herschel/PEP

Berta, S.; Magnelli, B.; Lutz, D.; Altieri, B.; Aussel, H.; Andreani, P.; Bauer, O.; Bongiovanni, A.; Cava, A.; Cepa, J.; Cimatti, A.; Daddi, E.; Dominguez, H.; Elbaz, D.; Feuchtgruber, H.; Förster Schreiber, N. M.; Genzel, R.; Gruppioni, C.; Katterloher, R.; Magdis, G.; Maiolino, R.; Nordon, R.; Pérez-García, A. M.; Poglitsch, A.; Popesso, P.; Pozzi, F.; Riguccini, L.; Rodighiero, G.; Saintonge, A.; Santini, P.; Sanchez-Portal, M.; Shao, L.; Sturm, E.; Tacconi, L. J.; Valtchanov, I.; Wetzstein, M.; Wieprecht, E.
Referencia bibliográfica

Astronomy and Astrophysics, Volume 518, id.L30

Fecha de publicación:
7
2010
Número de autores
37
Número de autores del IAC
4
Número de citas
121
Número de citas referidas
107
Descripción
The constituents of the cosmic IR background (CIB) are studied at its peak wavelengths (100 and 160 μm) by exploiting Herschel/PACS observations of the GOODS-N, Lockman Hole, and COSMOS fields in the PACS evolutionary probe (PEP) guaranteed-time survey. The GOODS-N data reach 3σ depths of ~3.0 mJy at 100 μm and ~5.7 mJy at 160 μm. At these levels, source densities are 40 and 18 beams/source, respectively, thus hitting the confusion limit at 160 μm. Differential number counts extend from a few mJy up to 100-200 mJy, and are approximated as a double power law, with the break lying between 5 and 10 mJy. The available ancillary information allows us to split number counts into redshift bins. At z ≤ 0.5 we isolate a class of luminous sources (LIR ~ 1011 L_&sun;), whose SEDs resemble late-spiral galaxies, peaking at ~130 μm restframe and significantly colder than what is expected on the basis of pre-Herschel models. By integrating number counts over the whole covered flux range, we obtain a surface brightness of 6.36±1.67 and 6.58±1.62 [ nW m-2 sr-1] at 100 and 160 μm, resolving ~45% and ~52% of the CIB, respectively. When stacking 24 μm sources, the inferred CIB lies within 1.1σ and 0.5σ from direct measurements in the two bands, and fractions increase to 50% and 75%. Most of this resolved CIB fraction was radiated at z ≤ 1.0, with 160 μm sources found at higher redshift than 100 μm ones. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Table 1 and Appendix A are only available in electronic form at http://www.aanda.org