Mid-Infrared Observations of Extended Lyman-Alpha Halos at High Redshift
Tracy Webb
Université McGill
Deep narrow-band surveys have detected an enigmatic population of
extended Lyman-alpha emitting nebulae at high redshift. These
so-called Lyman-alpha Blobs (LABs) have projected physical extents
of up to 200 kpc and Lyman-alpha luminosities of 10^44 ergs/s, but
the mechanism powering their ionization remains unclear. They are
prevalent in high-density regions which exhibit signs of intense
star formation and nucleic activity and indeed the largest sample
to date lies within in the SSA22 filament at z = 3.09. I will
discuss the results of the first large mid-infrared study of this
region using deep Spitzer IRAC and MIPS imaging. Through a study
of the rest-frame optical and near-infrared spectral energy
distributions of LABs I will show that many of these systems are
ULIRG-like, with tentative indications of AGN activity, and are
distinct from the more moderate star forming population of
Lyman-break galaxies in the SSA22 structure. I will close with
the implications of these results for the formation mechanism of
LABs within the context of galaxy evolution.
Date: | Thursday, 27 November 2008 |
Time: | 12:15 |
Where: | Université de Montréal |
| Pavillon Roger-Gaudry, Local D-460 |
Contact: | Pierre Bergeron |
|