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"Towards a complete census of High-z ULIRGs with Herschel"
Dr.George Magdis
CEA/Saclay, France
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When:  Friday 16 July 2010 at 2pm
Where: 2nd Floor Seminar Room

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Abstract:

Although local ULIRGs contribute a very small fraction of the IR
luminosity density, their cosmological importance increases with
increasing redshift. Many of their fundamental properties though, still
rely on indirect measurements, while there is evidence that methods of
detecting high-z ULIRGs are strongly affected by selection biases.

I will present a detailed study of the far-IR properties of a sample of
mid-IR selected z~2 star-forming dominated ULIRGs, based on Herschel
PACS and SPIRE  as part of the HERMES project. I will discuss how
Herschel observations:
-provide the means for a Td-unbiased study of high-z ULIRGs, 
-reveal a wide range of dust temperatures, suggesting a diversity of the
physical mechanisms that trigger star-formation on the early universe
-demonstrate that a large fraction of high-z ULIRGs are missed by
current ground based (sub)mm surveys.

I will then extend to z~3, considering a sample of ULIRG Infrared
Luminous Lyman Break Galaxies. I will first present a multi-wavelength
view of the star-formation activity at z~3 and put constraints on the
SFR of LBGs. Based on the large SFR of some LBGs though, it is somewhat
surprising that there are only few examples of direct submillimeter
detection for these galaxies, indicating that the far-IR properties are
still unclear.
Using PACS observations of GOODS-N as part of the PEP project, I will
then present first insights into the far-IR properties for a sample of
z~3 LBGs:
- Construct for the first time, the average SED of infrared luminous
LBGs from UV to radio wavelengths
- Put constraints on the dust temperature of the population showing that
LBGs are warmer than SMGs and observe for the first time the general
LIR-Td trend seen in the local universe, for UV-selected galaxies at z~3
- Shed light on the marginal detection of LBGs in current sub-mm surveys
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