Venice 06 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
Dec 17, 2015
Venice 06
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
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The Cosmic Infrared Background
Dole et al. (2006)
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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)
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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)
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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%)
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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)
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MIPS 24 µm surveys
Le Floc’h et al (2005)
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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)
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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)
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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 )
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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
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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
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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
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Zodiacal Background
Reach, private communication
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Asteroids in the Cosmos Field
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2sq degrees
• No cirrus emission• Detection limit to
420µJy (5)
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Main and Deep Area
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Deep area
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MIPS, IRAC and Galex
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Submm sources
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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
Z 0.5 1 1.5 2
67 µJy 10.5 11.0 11.7 12.0
420 µJy 11.2 11.8 12.5 12.8