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Star Formation in the Cosmic Web. Herv é Aussel, AIM Dave Sanders, Mara Salvato, Olivier Ilbert, David Frayer, Jason Surace, Nick Scoville, and the S-Cosmos team. The Cosmic Infrared Background. Dole et al. (2006). The Cosmic Infrared Background. COB: 23nW/m 2 /sr CIB: 24 nW/m 2 /sr
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Star Formation in the Cosmic Web Hervé Aussel, AIM Dave Sanders, Mara Salvato, Olivier Ilbert, David Frayer, Jason Surace, Nick Scoville, and the S-Cosmos team
The Cosmic Infrared Background Dole et al. (2006)
The Cosmic Infrared Background • COB: • 23nW/m2/sr • CIB: • 24 nW/m2/sr • COB/CIB~1 • Locally: • O/I = 0.3 Dole et al. (2006)
The Resolution of the CIB • COB/CIB ~1 indicates that • There is a strong evolution of the infrared emission of galaxies • Directly probed by SCUBA (850 µm) • Indirectly probed by • ISOCAM (15 µm) • MIPS (24 µm)
ISOCAM surveys • Resolved the CIB at 15 µm • Resolved 70% of the CIB at 140µm • LIRGs ~60 % • ULIRG ~ 25 % • Massive disks galaxies between z=0.5 and z=1.2 • Liittle AGN contribution (< 20%)
MIPS 24 µm Surveys • Strong Evolution also observed at 24µm • Strong evolution of LIRGs and ULIRGs • Massive galaxies • 40 % of the M > 2x1010Msol are undergoing a starburst at z~0.7 (Bell et al, 2005) • Little AGN contribution Papovich et al. (2004)
MIPS 24 µm surveys Le Floc’h et al (2005)
Open Questions: • What drives the SB? • Most of the galaxies responsible for the evolution belong to “Structures” • Elbaz & Cesarsky (2003) • Bias: is mass a main parameter or are we biased by environment? • Major Merger? • Hammer et al. (2005)
Open Questions • What about dense environments ? • Infrared MDR in some clusters: • A1689: 30 galaxies detected at 15µm (Duc et al., 2002) • Verified in some clusters, not in others • Age of the structure might be a key parameter (Coia et al., 2005)
S-Cosmos • Map the 2 sq degree of the Cosmos field with IRAC and MIPS. • MIPS: • goal is to reach 67 µJy (5 ) at 24µm • 36 hrs • Full area at 420 µJy (5 ) • Test field at 67 µJy (5 )
COSMOS Field • Low Extinction • Low Background • IRAS 100 m: • COSMOS: 0.9 MJy/sr • Lockman: 0,5 MJy/sr • XMM-LSS: 1.3 Mjy/sr: • No bright radio/X-ray source • 10:00:28.6+02:12:21
COSMOS Field • Low Extinction • Low Background • IRAC 8 m: • COSMOS: 6.9 MJy/sr • Lockman: 5.0 MJy/sr • XMM-LSS: 7.1 Mjy/sr: • No bright radio/X-ray source • 10:00:28.6+02:12:21
COSMOS Field • Low Extinction • Low Background • MIPS 24 m: • COSMOS: 32.3 MJy/sr • Lockman: 18.4 MJy/sr • XMM-LSS: 31.1 MJy/sr • At most a loss of 20% in sensitivity w/r to non equatorial fields • No bright radio/X-ray source • 10:00:28.6+02:12:21
Zodiacal Background Reach, private communication
2sq degrees • No cirrus emission • Detection limit to 420µJy (5)
Conclusions • S-Cosmos MIPS pilot project has demonstrated the • Need to probe below 100 µJy • to resolve a significant fraction of the CIB • To probe the LIRG regime out to z~2