9222(  1) - 12/20/00 23:47  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      9222
                                                       Version: 1
                                                       Check-in Date: 20-Dec-2000
                                                                      23:40:28

1.Proposal Title:
The Fundamental Plane of  field early- type galaxies from z~ 0.7 to z=0
------------------------------------------------------------------------------------
2. Proposal For  3. Cycle
AR               10
------------------------------------------------------------------------------------
4. Investigators
                                                                                     Contact?
    PI: Tommaso Treu                      Space Telescope Science Institute
   CoI: Dr. Massimo Stiavelli             Space Telescope Science Institute             N
   CoI: Prof. Giuseppe Bertin             Scuola Normale Superiore                      N
   CoI: Prof. Marcella Carollo            Columbia University                           N
   CoI: Dr. Stefano Casertano             Space Telescope Science Institute             N
   CoI: Dr. Palle M\o ller                European Southern Observatories               N

------------------------------------------------------------------------------------
5. Abstract

The history of field early-type galaxies (E/S0) is a key ingredient to constrain
galaxy formation theories: in hierarchical clustering models they form at z<~1
through major mergers, while in monolithic collapse models they form earlier and
evolve passively thereafter. We are investigating the star formation history of
field E/S0 using the redshift evolution of the Fundamental Plane (FP) as
diagnostics. The first (z=0.1-0.4) part of the project-- based on HST images and ESO
3.6m spectra-- provided the following results: i) the FP exists and is tight out to
z=0.4; ii) under the assumption of passive evolution of single burst populations,
the z of formation is constrained to be z=0.8-1.6 (Omega=0.3, Omega_Lambda=0.7);
iii) field and cluster data are consistent within observational errors and cosmic
scatter. We are currently obtaining spectra at the VLT (30 hrs approved on FORS), in
order to extend the project to z~0.7, where the diagnostics becomes dramatically
more sensitive. By going to z~0.7, we will pinpoint the epoch of formation, and we
will be able to detect relatively small differences in star formation history
between field and cluster. In order to perform the highest redshift--and most
promising--part of the study, it is essential to analyze 107 HST-WFPC2 images,
already available in the archive. With this proposal we are seeking the necessary
funds.
------------------------------------------------------------------------------------
                                                9222(  1) - 12/20/00 23:47  - [  2]

            Summary Form for Proposal  9222

  Item                         Used in this proposal
------------------------------------------------------------------------------------------------------------------------------------
  Proposal Category            AR
------------------------------------------------------------------------------------------------------------------------------------