Very Blue UV-Continuum Slopes of Star-Forming Galaxies at z∼7 and the Evolution to z∼2-4.

The new WFC3/IR instrument on HST enables us to survey the sky in the near-IR 40× more efficiently than ever before, permitting enormous strides in the identification and characterization of galaxies at z≥7. Already, deep wide-area observations exist over some ∼52 arcmin2 in the HUDF09+ERS fields. With these data, we have been able to identify more than 60 z∼7 galaxy candidates, more than 40 z∼8 galaxy candidates, and even some possible z∼9 galaxies over a 3 magnitude range in luminosity, adding significantly to the 20-30 z∼7 candidates known prior to WFC3/IR. One of the most interesting observables to examine in these high redshift galaxies are the UV-continuum slopes, since it provides us with constraints on the dust content, metallicities, ages, and possibly escape fractions of low-mass star-forming galaxies at very early times. Here, I provide a brief summary of our findings on the UV-continuum slopes β of z∼7 galaxies from the early ultra-deep WFC3/IR data over the HUDF. [ABSTRACT FROM AUTHOR]