GEMS Collaboration Meeting Baltimore, Jan 20-21, 2003 What do we want to accomplish? Get to know each other Take stock of our status quo Data, software (tools),goals,... Better define data products Prioritize science goals Define approach Clarify team responsibilities (Re-)define schedule GEMS vs. Other current activities 2 Galaxy Population over the last 10 Gyrs How many stars have formed since z~1.2 ? In which Galaxies? Mostly during in star-bursts, or quiescently? Which galaxies are old already? How did the clustering of galaxies evolve ? Mass clustering vs. galaxy bias. Always a morphology-density relation? When and how did bulges and disks form ? How did the merger rate evolve? Is there an angular momentum problem Do disks grow inside out? What makes AGNs light up? Dramatic drop in AGN lum. density since z~1 3 What Data do we Need ? (to tackle this via look-back observations) Galaxy properties as a function of: Redshift/Epoch with t/t H ~1 Note: z=1.2 t look-back = 10 Gyrs Luminosity Spectral Energy Distribution (SED) Internal structure (size, bulge-to-disk, etc.) Environment a multi-dimensional parameter space + account for large-scale fluctuation in the galaxy and mass distribution. + include typical galaxies at all epochs i.e. reach below L * at all redshifts 4 Survey Requirements Several 10,000 galaxies with Redshifts to z>1 (good to a few percent) Faint flux limit m r ~24 SEDs, including (rest-) UV and optical Several large fields Co-moving size > 5 Mpc High-resolution (0.1) imaging typical scale lengths are 0.3 asec two-color rest-frame B at all z 5 Existing Faint Surveys CFRS Lilly, LeFevre, et al. I