ACS Backup Proposals

The Advanced Camera for Surveys (ACS) is the workhorse instrument on the Hubble Space Telescope, accounting for over 70% of the scheduled programs. ACS suffered two anomalies during 2006, leading to a switch to operations on side 2 electronics and a reconfiguration of the use of the three ACS cameras (WFC, SBC and HRC). On the morning of January 27 2007, HST entered inertial safe mode, apparently as a result of a serious failure of the side 2 electronics.

In the absence of ACS, HST would quickly exhaust the available Cycle 15 NICMOS, WFPC2 and FGS observations. To mitigate the science impact of this eventuality, STScI issued a call for additional large backup programs using those three instruments. The programs were to be held in reserve, and inserted into the observing schedule only in the event of a serious ACS anomaly.

A total of 35 proposals were submitted by the deadline of November 3 2006, including 9 with ESA scientists as PI. The proposals were reviewed and graded by members of the Cycle 15 Time Assignment Committee. Highly ranked proposals were assessed for technical feasibility by members of the appropriate instrument teams at STScI. Based on the TAC rankings and the feasibility analysis, the Director selected the following six proposals for further development:

GO 11079      L. Bianchi, Johns Hopkins University:
         Imaging of star forming regions throughout the Local Group

GO 11080     D. Calzetti, University of Massachusetts:
         Exploring the scaling laws of star formation

GO 11081     G. Clementini, University of Bologna:
             RR Lyrae stars in M31 globular clusters

GO 11082     C. Conselice, Univ. of Nottingham:
                NICMOS imaging of GOODS

GO 11083      P. Cote, Herzberg Institute, Canada:
    The structure, formation and evolution of galactic cores and nuclei

GO 11084      D. Zucker, Institute of Astronomy, Cambridge:
    Probing the least luminous galaxies in the local universe

Together, these programs provide 300-400 orbits of science observations at any time of the year. The proposals are considered as Normal GO programs and have 0 proprietary time.