The UV Luminosity Function of star-forming galaxies via dropout selection at redshifts z ~ 7 and 8 from the 2012 Ultra Deep Field campaign
A paper on "The UV Luminosity Function of star-forming galaxies via dropout selection at redshifts z ~ 7 and 8 from the 2012 Ultra Deep Field campaign" has been submitted to the Astrophysical Journal. A preprint is available at http://www.arxiv.org/abs/1212.4819:
The UV Luminosity Function of star-forming galaxies via dropout selection at redshifts z ~ 7 and 8 from the 2012 Ultra Deep Field campaign
Authors:
Matthew A. Schenker, Brant E. Robertson, Richard S. Ellis, Yoshiaki Ono, Ross J. McLure, James S. Dunlop, Anton Koekemoer, Rebecca A. A. Bowler, Masami Ouchi, Emma Curtis-Lake, Alexander B. Rogers, Evan Schneider, Stephane Charlot, Daniel P. Stark, Steven R. Furlanetto, Michele Cirasuolo
Abstract:
We present a catalog of high redshift star-forming galaxies selected to lie within the redshift range z ~ 7-8 using the Ultra Deep Field 2012 (UDF12), the deepest near-infrared (near-IR) exposures yet taken with the Hubble Space Telescope. As a result of the increased near-infrared exposure time compared to previous HST imaging in this field, we probe 0.65 (0.25) mag fainter in absolute UV magnitude, at z ~ 7 (8), which increases confidence in a measurement of the faint end slope of the galaxy luminosity function. Through a 0.7 mag deeper limit in the key F105W filter that encompasses or lies just longward of the Lyman break, we also achieve a much-refined color-color selection that balances high redshift completeness and a low expected contamination fraction. We improve the number of drop-out selected UDF sources to 47 at z ~ 7 and 27 at z ~ 8. Incorporating brighter archival and ground-based samples, we measure the z ~ 7 UV luminosity function to an absolute magnitude limit of M_UV = -17 and find a faint end Schechter slope of \alpha = -1.87+/- 0.18. Using a similar color-color selection at z ~ 8 that takes account of our newly-added imaging in the F140W filter, and incorporating archival data from the HIPPIES and BoRG campaigns, we provide a robust estimate of the faint end slope at z ~ 8, \alpha = -1.94 +/- 0.23. We briefly discuss our results in the context of earlier work and that derived using the same UDF12 data but with an independent photometric redshift technique (McLure et al 2012).
The Hubble Ultra Deep Field 2012 program is a collaboration between the California Institute of Technology, the University of Arizona, the University of Edinburgh, the Space Telescope Science Institute, the University of California Los Angeles, the University of Tokyo, and the Institut Astrophysique de Paris. Support for this Program was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research In Astronomy, Incorporated, under NASA contract NAS5-26555.
