About This Article
STScI is pleased to announce the second opportunity to propose target lists for the “Schedule Gap” program. Starting in Cycle 24, STScI has been scheduling ACS observations to make use of those orbits in which normal GO or SNAP observations cannot be scheduled. Targets are selected late in the construction of the weekly HST schedule after all other opportunities are exhausted. Initially, Program 14840 obtained observations of 151 galaxies – approximately 10 observations per month as a pilot project using a catalog of 500 NGC galaxies. Following the recommendation of the 2016 meeting of the Space Telescope Users Committee (STUC), STScI solicited proposals from the community from which three were selected in late 2017 in consultation with the STUC.
These programs were GO 15444 “An ACS Schedule Gap Imaging Survey of Nearby Active Galaxies” (PI: Aaron Barth, UC Irvine) for 543 targets, GO 15445 “Gems of Galaxy Zoos” (PI: William Keel, U. Alabama) for 300 targets, and GO 15446 “HST’s Low Redshift Archive of Interacting Systems” (PI: Julianne Dalcanton, U. Washington). As of November 2022, HST has observed 205, 174, and 211 targets from these programs (for a total of 741 targets including pilot program 14840) – observations which would not otherwise have been obtained. As their target distributions on the sky have become less effective in filling gaps, and as it has been five years since the last opportunity to propose such observations, we are terminating the current programs and soliciting another round of gap filer proposals.
At this time we are soliciting proposals for additional source catalogs and/or creative advice in using this scheduling opportunity. Proposers should be aware that this lowest priority scheduling has multiple restrictions. These include: (1) limiting the visit duration to ~25 minutes or less, (2) being broadly distributed on the sky, (3) use of ACS/WFC only, (4) no opportunity for changes in the proposal after the start of execution, and (5) no observatory-level special requirements (e.g., ORIENT). STScI will make these data non-proprietary and funding will not be provided. It is not possible to predict in advance what fraction of the catalog will be observed, when the observations will occur, or which objects will be selected for observation.
To propose, a two-page PDF file should be sent to hubblereview@stsci.edu no later than December 22, 2022. The proposal should briefly explain the scientific motivation for the observations, their value within the larger context of the HST archive, the basic parameters of the proposed source catalog (e.g., number of objects, types of objects, range of apparent magnitudes, sizes, distribution on the sky, etc. – a complete and final list is not required at this time). The proposal should follow the guidelines for anonymous proposal review associated with the Hubble annual call for proposals. Basic observing parameters should also be specified (filters, exposure time, number of exposures, etc.) The proposals will be evaluated by a panel and the STUC, with recommendations to the STScI Director. The successful proposer(s) will be expected to submit an APT file in consultation with STScI staff.
Questions may be directed to hubblereview@stsci.edu for policy or technical issues.
Note: Additional information on several of these programs may be found at:
https://www.zooniverse.org/projects/ngc3314/zoogems/talk/1396.
There are summary papers describing programs 14840 (Bellini et al.2017 STScI ISR ACS 2017-12), 15444 (Kim et al., 2021 ApJ Suppl. 256, 40) and 15445 (Keel et al. 2022 AJ163, 150).