Bibcode
Altieri, B.; Berta, S.; Lutz, D.; Kneib, J.-P.; Metcalfe, L.; Andreani, P.; Aussel, H.; Bongiovanni, A.; Cava, A.; Cepa, J.; Ciesla, L.; Cimatti, A.; Daddi, E.; Dominguez, H.; Elbaz, D.; Förster Schreiber, N. M.; Genzel, R.; Gruppioni, C.; Magnelli, B.; Magdis, G.; Maiolino, R.; Nordon, R.; Pérez-García, A. M.; Poglitsch, A.; Popesso, P.; Pozzi, F.; Richard, J.; 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.L17
Advertised on:
7
2010
Revista
Número de citas
22
Número de citas referidas
15
Descripción
Gravitational lensing by massive galaxy clusters allows study of the
population of intrinsically faint infrared galaxies that lie below the
sensitivity and confusion limits of current infrared and submillimeter
telescopes. We present ultra-deep PACS 100 and 160 μm observations
toward the cluster lens Abell 2218 to penetrate the Herschel confusion
limit. We derive source counts down to a flux density of 1 mJy at 100
μm and 2 mJy at 160 μm, aided by strong gravitational lensing. At
these levels, source densities are 20 and 10 beams/source in the two
bands, approaching source density confusion at 160 μm. The slope of
the counts below the turnover of the Euclidean-normalized differential
curve is constrained in both bands and is consistent with most of the
recent backwards evolutionary models. By integrating number counts over
the flux range accessed by Abell 2218 lensing (0.94-35 mJy at 100 μm
and 1.47-35 mJy at 160 μm), we retrieve a cosmic infrared background
surface brightness of ~8.0 and ~9.9 nW m-2 sr-1,
in the respective bands. These values correspond to 55±24% and
77±31% of DIRBE direct measurements. Combining Abell 2218 results
with wider/shallower fields, these figures increase to 62±25% and
88±32% CIB total fractions, resolved at 100 and 160 μm,
disregarding the high uncertainties of DIRBE absolute values.