Dr. Cooray will carry out a comprehensive research program to characterize the underlying astrophysical and cosmological information contained in the infrared background (IRB) spatial anisotropies at near- and far-IR wavelengths. In the near-IR regime, signatures of primordial galaxies in the background spatial fluctuations will be studied. At far-IR wavelengths, clustering information of dusty, star-forming galaxies will be measured. The main goal of this research program is to expand the science case for anisotropy measurements of IRB and to provide a strong theoretical background to interpret these measurements just as the case has been with respect to CMB anisotropy experiments.
As a part of this research project, Dr. Cooray plans to provide training and research experiences for students, with an emphasis on creating opportunities for undergraduate students. This includes direct involvement in international collaborations such as Akari, based in Japan, and Herschel SPIRE, based mostly in the UK. Students will attend collaboration meetings in these countries and will be trained to work with and learn from foreign partners. The PI plans to integrate elements of this research program and other topics in cosmology into a Computational Physics course Dr. Cooray teaches at UC Irvine where the students are recruited for the research program. Over the next three years, Dr. Cooray will also develop a completely new course on how to do "Order of Magnitude Physics" targeting juniors and will also make available the course material publicly from a website. Dr. Cooray will also update an existing Voyager-era "Space Science" course, in the introductory astronomy sequence targeting non-science majors, to a course on "Space Astronomy" as a way to bring new astronomical missions and their results to the classroom.
This award is funded by the NSF Division of Astronomical Sciences
. We have analyzed a large dataset of near-IR images from IRAC on Spitzer and NICMOS on HST, and have combined IR data and catalogs with optical and UV ACS data (Sullivan et al. 2007; Cooray et al. 2007). 2. Our studies have conclusively demonstrated that there is no significant evidence for a large surface density of Population III stars during reionzation that dominates the IR extragalactic background light (Cooray et al. 2007). 3. We have discovered a substantial population of low-luminosity dwarf galaxies at z=2 to 3 that contributes about 30% of the stellar mass density in these redshift ranges and is significant contributor to the residual IR background fluctuations, though these sources remain unresolved and undetected individually in existing IR images (Chary et al. 2008) 4. Our work has shown that it is possible to rule out extreme models of cosmological reionization where reionization begins at z> 15 and UV photon background is dominated by massive Pop-III stars. We have motivated a necessary survey during the warm-phase of the Spitzer mission (as part of a working group that advised Spitzer Science Center on possible science studies at near-IR wavelengths) and has proposed a necessary survey at lower wavelengths with WFC3 on HST as part of cycle 17 observations. 5. Our team supported as Co-Is close to 4 proposal that were submitted to the Spitzer Warm Mission in 2008. Unfortunately, none were selected. We, however, plan to analyze and interpret background fluctuations in deep imaging data collected during the Warm phase. 6. We led a proposal to the Herschel Key Project program and was successful. We are the lead team in US for Herschel ATLAS survey, imaging 600 deg^2 in the parallel mode with SPIRE and PACS. 7. The PI led a White Paper to propose an EBL explorer at Jupiter distances for absolute photometric measurements outside the zodiacal cloud with 52 other co-authors. A concept mission is now studied with a smaller team bases at JPL. In March 2010, PI organized a workshop devoted to this topic at UC Irvine. We are now developing a concept study instrument to be put on an outer Solar system mission. 9. CIBER was launched in February 2009 and a first paper describing the results from the first flight is prepared for submission to ApJ. 10. Using an archival analysis of multi-frequency Boomerang 2003 polarization data, we place the first constraints on the Sunyave-Zel'dovich contribution at tens of arcminute angular scales. 11. Herschel was launched in May 2009. Started collecting data few months later and observed several of the first science fields of both the HerMES survey of the SPIRE Instrument GTO science team (in which PI's team at UCI is a lead participant in terms of data analysis) and the Herschel ATLAS (a separate key program of Herschel that PI help propose in 2007 and in which PI of the CAREER award is the PI from NASA side). 12. 32 papers describing first science results were submitted for publication in a special issue of A&A on Herschel on March 31, 2010. The papers are under peer-review now and are not listed in the publications related to this award for this year. We will list them next year when they are published. PI is a coauthor of all of these and lead author in one of them. PI's team led a second paper with first authorship to postdoc Serra. PI's undergraduates are also coauthors in at least one of the publications. 13. We cataloged the largest sample of lensed sub-mm galaxies (Wardlow et al. 2012), with initial results appearing in Negrello et al. 2010 Science (and a Discovery News article related to those results on the NSF website). 14. We published the first measurement of the CIB power spectrum with Herschel imaging data, Amblard et al. 2011 Nature. 15. We measured the intrahalo light fraction of distant galaxies using the angular fluctuations of the near-IR background in Spitzer Space Telescope images (Cooray et al. 2012 Nature in press).
