Keeping Hubble Productive

Brad Whitmore,, & Karen Levay,

One of the primary goals of the Space Telescope Science Institute is to help the astronomical community to maximize the science output from the Hubble Space Telescope. While science return is not always easy to define or measure, the number of papers published per year based on Hubble results is at least a quantifiable metric. Paper rates are the primary subject of this article.

Figure 1 shows Hubble papers per year since the telescope was launched in 1990. Apai et al., 2010 (PASP, 122, 808) describe the methodology behind these data.

Figure 1A major reason for Hubble’s increasingly high scientific productivity over the last decade is research using the Hubble archive. The number of papers based on the archive has risen from about 200 papers per year in 1998 to well over 400 in 2011, while the number of papers from general observer (GO) observing teams—and not using the archive—has remained roughly constant over the same period.  Because the pool of Hubble archival users is an order of magnitude larger than the number of GOs each year, we must strive to make the archive as useful as possible.

Apai et al. raise the question of whether the number of Hubble papers per year would increase or decrease if the mix of large and small programs were changed. They also comment that “only large programs have the potential to lead to high-impact articles and data sets with lasting legacy value.” Indeed, the high impact of large programs is part of the rationale for the Multi-Cycle Treasury Program (MCTP).

Figure 2 shows a comparison of the cumulative number of papers per orbit for Treasury programs, large (but not Treasury) programs, and normal GO programs. As a reminder, “large” programs are allocated more than 100 orbits, and are usually focused scientific projects with standard data proprietary periods. Treasury programs are generally on the same scale as large programs, but have broader scientific application, the data are released immediately, and the proposal team makes a commitment to produce high-level science products (HLSPs). We find that the cumulative paper counts per orbit for large programs are lower than for regular proposals. The Treasury programs, however, are the highest of the lot, which is a good sign for the future, since we are currently investing a relatively large fraction of observing time in this type of program.