The UV-selected galaxy luminosity function at z > 6 provides a crucial observational constraint on the earliest phases of galaxy evolution and the likely role galaxies play in cosmic reionization. Within this context, we present new results on the galaxy luminosity function at redshifts 7 <z <9 arising from the unprecedented deep near-IR imaging data provided by the Hubble Space Telescope (HST) Ultra Deep Field 2012 (UDF12) program undertaken with the near-infrared arm of the Wide Field Camera 3 (WFC3/IR). Compared to previous data in the UDF, the new UDF12 program quadruples the integration time in the vital Y-band filter (F105W), reaching a 5-sigma detection limit of 30.0 AB, and provides the first ultra-deep imaging (5-sigma limit=29.8 AB) in the previously unused J-band/F140W filter. Using a combination of traditional drop-out selection and photometric redshift techniques we have assembled a well defined sample of over 200 galaxies at z>6.5, drawn from UDF12 and wider field HST imaging sampling a total area of 300 square arcmin. Our combined analyses provide the most accurate measures to data of the faint end of the luminosity function at z=7 and z=8, and the first census of the population at z=9. High redshift galaxy samples derived from the UDF12 program will provide a premier resource for studying high-redshift galaxy evolution in the era prior to the launch of the James Webb Space Telescope.
|Publication status||Published - 1 Jan 2013|
|Event||AAS, 221st Meeting of the American Astronomical Society - California, Long Beach, United Kingdom|
Duration: 6 Jan 2013 → 10 Jan 2013
|Conference||AAS, 221st Meeting of the American Astronomical Society|
|Period||6/01/13 → 10/01/13|