This team will extend their DEEP2 spectroscopic survey, using high dispersion spectra with the DEIMOS multi-object spectrograph at the Keck telescopes for galaxies in the redshift range 0.5 < z < 1.5. This redshift range represents 85% of cosmic history, over the time when most of the galaxy mass was assembled and galaxies formed their disks. The new DEEP3 survey concentrates on the extended Groth strip, an area on the sky that has been observed with many of NASA's great observatories. The team will use these and other archives to compile a panchromatic catalog describing their survey galaxies over a wide wavelength range from radio to X-rays. DEEP3 will push the limit of observations 2.5 times fainter than DEEP2, tripling the number of measured galaxies.
The team will estimate the rate at which their survey galaxies are forming their stars, by measuring their brightness in the ultraviolet, infrared and radio, and by using diagnostics based on the optical emission lines measured in the DEEP2 and DEEP3 surveys. They will investigate a tight relation found in DEEP2 between the rate of star formation in a galaxy and the mass in stars already present, and examine how galaxy environment and morphology affect that relation. Team members will use observations from the DEEP2 and DEEP3 surveys to study how scaling laws such as the Tully-Fisher relation (between a galaxy's luminosity and its circular rotation speed) change over time as disk galaxies are assembled. They will investigate the role of active galactic nuclei in star formation, and use X-ray observations to search for signs of faint hidden active nuclei.
Graduate students and postdoctoral scholars will be trained as they participate in the research. As has been done for the earlier DEEP2 survey, data including redshifts, photometry, and spectra would be released to the astronomical community. Multiwavelength images from DEEP2, along with an interactive redshift catalog, are already available on google sky; more data will be added as the new survey proceeds.
For the last year of this collaborative research proposal, I returned to an old but unfinished project that had NSF support. From the CMB dipole anisotropy, we know that the Milky Way and neighborhood are moving at 640 km/s in a direction 40° off from the Virgo cluster, which one would think should be our center. The question is why? Why is the Milky Way moving at such a high velocity relative to the CMB frame, which defines the rest frame? By using a new catalog of peculiar velocities as well as a new catalog that covers almost 4Π steradians, I have redone the analysis we first published in 1995. This time the chi-squared per degree of freedom is one, whereas the old value was two, indicating the data finally fits the model. This work is now published, and I am giving talks at international conferences. The major result is that the peculiar motion of the Milky Way can be explained by the gravity field to a distance of 100 Mpc. This is an important result as it precludes nonstandard explanations for the peculiar motion. A figure showing the results is below. The left-hand column is the peculiar velocity field as defined from a smoothed version of the catalog of peculiar velocities, while the central column is the expected gravity field. The rightmost column is the difference. The four rows of data are for galaxies in selected distances from us. the important point is the incredible match of the first and second rows of plots, As they were derived completely independently. The fact that they agree so well is a remarkable statement that our understanding of cosmological theory works very well. Prior to last year, I was heavily involved in the collaborative research project. We now have excellent spectroscopic coverage of a very deep field that has outstanding HST imaging. This database is now useful for many different research questions. The typical object that we target is at a light distance of 8-12 billion years. Remember the universe is 13.8 billion years old. Thus we can see galaxies as they were in the past, and compare it to nearby galaxies. From this we have learned about the stellar evolution and merging history of typical galaxies.
