IAU01139
Presentation type requested: EITHER
ULTRA-DEEP NEAR-IR IMAGING OF POPIII GALAXY CANDIDATES
Richard Johan
Observatoire Midi-Pyrenees, Toulouse
We report the first results obtained in our ultra-deep near-IR survey with ISAAC/VLT, aimed at the detection of Population III objects at high-z using lensing clusters as natural Gravitational Telescopes. The new Pop III models by Schaerer (2002, 2003) have been used to derive the observational properties expected for the first galaxies, namely the expected magnitudes and colors, as well as line intensities for the main emission lines. According to our modeling, it is possible to define robust selection criteria to find PopIII galaxies based on broad-band near-IR photometry. The magnification in the core of lensing clusters improves the search efficiency and subsequent spectroscopic studies. Here we present the first results of this survey. Several z ~ 8-10 PopIII candidates have been found satifying our photometric criteria. The number of candidates found using the Gravitational Telescope is compared to the one achieved in blank fields with similar photometric depth in the near-IR. The different number density results are compared to expectations, using a simple modeling scheme to estimate the number counts in cluster and blanck fields. We discuss on the possible implications of these preliminary results to constrain the formation epoch and the properties of the first stars in galaxies.
Pello Roser , Le borgne Jean-francois
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