One of the major themes in the study of galaxy formation is identifying and understanding the earliest galaxies. The study of galaxies at the highest redshifts is of enormous importance, not only because it will enable us to chart unknown territory, but also because it will shed light on a number of key cosmological questions. These include understanding the history of reionization, and the formation of the first stars, galaxies and heavy elements in the first billion years after the Big Bang. Our program aims to discover galaxies at z > 6 and to address these questions. Armed with the unprecedented capability brought by WFC3, our pure-parallel program will efficiently probe the critical 6 <z <9 range and make a unique contribution in this field at minimal cost in telescope time. We will identify galaxy candidates at 6 <z <9 utilizing the now-standard dropout technique, using both the IR and the UVIS channels of the WFC3. The passbands to be observed are F098M, F125W and F160W in the IR, and F600LP in the UVIS. We will search for F098M-dropouts and F600LP-dropouts, which are galaxy candidates at 7.4 <z <8.8 and 6.0 <z <7.4, respectively. Our emphasis is the higher redshift range at 7.4 <z <8.8 as this is currently at the redshift frontier. Meanwhile, we also consider the lower redshift range at 6.0 <z <7.4 for two reasons. Firstly, the sample of galaxies in this regime is still very small -- this is especially true for 6.5 <z <7.4. More importantly, including this lower redshift range in our study will enable us to assess the evolution of galaxies from z ~ 6 to ~ 9, which can be done by comparing the samples in these two redshift bins. As the two samples will be derived from the same data set, systematic effects will be minimized. There is another similar pure-parallel program approved in this cycle, led by M. Trenti. Trenti et al.'s program P11700 will use the same IR filters as ours, and the only difference between the two programs is that they will use F606W instead of F600LP in the UVIS. For this reason, their data will not be suitable for identifying galaxies at 6.0 <z <7.4. However, their data will be as good as ours in searching for galaxy candidates at at 7.4 <z <8.8. Both ours and Trenti et al.'s programs have zero proprietary period. We outline our need to incorporate the Trenti et al. data in our project in section IV.
|Effective start/end date||5/1/10 → 4/30/12|
- National Aeronautics Space Administration (NASA): $56,866.00