The Space Telescope Science Institute is soliciting input from the community on two important potential new initiatives that can be addressed by the Hubble Space Telescope in future cycles, specifically “Deep Fields: Beyond the HUDF” (deadline for white papers: 31 August 2012, for notices of intent: 1 August 2012) and “Science Requiring Very Large Programs” (deadline for white papers: 31 August 2012).
1. Deep Fields: Beyond the HUDF
Deep imaging observations with Hubble Space Telescope have made seminal contributions to our understanding of galaxy assembly and evolution. The 2004 Hubble Ultra Deep Field with the Advanced Camera for Surveys enabled galaxy evolution studies out to redshift z~5, and the 2009 follow-up with the infrared channel of the Wide Field Camera 3 advanced this frontier to z~10. Programs such as GOODS, COSMOS, GEMS, and CANDELS have expanded Hubble's deep imaging coverage to broader regions, but there remains only one field with the depth and wavelength coverage of the Hubble Ultra Deep Field (HUDF). After consultation with the Space Telescope Users Committee and other members of the astronomical community, the Space Telescope Science Institute's Director, Dr. Matt Mountain, has decided to explore the possibility of devoting a substantial proportion of Director’s Discretionary time in Cycles 21-23 to a new HST Deep Fields Initiative. The overall goals are twofold: to extend our knowledge of the cosmic frontier at high redshifts through the collection of data that only HST is capable of obtaining, and to lay the groundwork for future observations of the early universe with the James Webb Space Telescope and other observatories.
A working group has been chartered to assess the urgency of pursuing this science with Hubble. The working group will define and optimize the science goals that should be addressed by any such program, and will identify appropriate strategies for reaching those goals. In the latter context, the working group will consider the number and locations of fields that should be observed to achieve these science goals, as well as an appropriate suite of filters and observing times for a core set of observations. Many strategies are possible, for example:
- Creating two or more multi-wavelength HUDF-like fields, well separated on the sky from the current HUDF;
- Targeting fields at ultraviolet-visible wavelengths with HST, with the expectation that the observing community will propose follow-up observations at longer wavelengths with HST and/or JWST;
- Choosing fields centered on strong-lensing clusters to probe the high redshift universe;
- Selecting fields adjacent to near-field targets (e.g., LMC, SMC, M31) that can also probe faint sources in the local universe.
The working group deliberations will occur in the July to September timeframe. Members of the working group include: James Bullock (UC-Irvine, Chair), Mark Dickinson (NOAO), Steven Finkelstein (UT Austin), Adriano Fontana (INAF, Rome), Ann Hornschemeier Cardiff (GSFC), Jennifer Lotz (STScI), Priya Natarajan (Yale), Alexandra Pope (U. Massachusetts), Brant Robertson (U. Arizona), Brian Siana (UC-Riverside), Jason Tumlinson (STScI), and Michael Wood-Vasey (U. Pittsburgh).
If implemented, the new deep field observations will be scheduled in Cycles 21-23 (October 2013 - September 2015), after the completion of the HST Multi-Cycle Treasury Programs in Cycle 20. All data will be non-proprietary. Opportunities to supplement these core observations and perform archival research will be available through the standard yearly HST Call for Proposals, with the Cycle 21 call to be released in December 2012. To the extent possible, the observations will be coordinated with other observatories (Chandra, Spitzer, JWST, Herschel, ALMA, etc).
We strongly encourage the community to provide the working group with input and suggestions, in the form of short (1-2 page) white papers, on the science that can be enabled by additional Hubble deep fields. Suggestions for near-field science opportunities within these deep fields, field locations, and observing strategies are encouraged. We also welcome comments, positive or negative, on the overall concept of Director's Discretionary Time support for further deep field science. Input should be sent in the form of plain text, Microsoft Word document, or PDF document to firstname.lastname@example.org by August 31, 2012. Unless you indicate that you prefer this input be confidential, all correspondence sent to this email address will be shared with the deep fields working group.
If you plan to submit a white paper, please send a notice of intent containing an author list, title, and brief subject description to the same address by August 1, 2012.
2. Science Requiring Very Large Programs with HST
HST observations, both imaging and spectroscopy, enable frontier science in many areas beyond galaxy formation and evolution. In 2009, we polled the community for white papers describing science topics that could profit from substantial (>350 orbit) allocations of time. Based on that process, we instituted the Multi-Cycle Treasury Call for Proposals in 2010, which resulted in the selection of the PHAT, CANDELS, and CLASH programs. Those programs were implemented starting in Cycle 18 and are expected to draw to a close in Cycle 20.
We are currently considering whether to enable submission of MCT-scale proposals in future cycles to tackle science priorities beyond those addressed through the deep field initiative and previous MCT programs. We are therefore requesting that interested members of the community submit short (1-2 page) white papers summarizing science programs that could be enabled by very large (350-500 orbit) HST programs. White papers describing why Hubble should not undertake such observations are also permitted. The white papers should be sent in the form of plain text, Microsoft Word document, or PDF document to VLGOHST@stsci.edu by August 31, 2012. These submissions will be held confidential, and reviewed by a small committee. That committee will not select specific science programs or themes; it will make a recommendation to the STScI Director on whether MCT-scale programs should be considered by future HST time allocation committees.