8742( 1) - 12/30/99 13:01 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8742 Version: 1 Check-in Date: 30-Dec-1999 12:31:18 1.Proposal Title: The Millisecond Pulsars of 47 Tucanae: Mining the Unique Stellar Equivalent of the Hubble Deep Field ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle AR 9 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Bruce Margon University of Washington CoI: Dr. Eric Deutsch University of Washington N CoI: Dr. Scott Anderson University of Washington N CoI: Dr. Richard Manchester Australia Telescope Nat'l Facility, CSIRO N CoI: Dr. Andrew Lyne University of Manchester, Jodrell Bank N CoI: Dr. Fernando Camilo University of Manchester, Jodrell Bank N CoI: Mr. Paulo Freire University of Manchester, Jodrell Bank N ------------------------------------------------------------------------------------ 5. Abstract Millisecond pulsars (MSPs) in binary systems hold the key to a number of important problems in astronomy, involving fields as disparate as stellar evolution, neutron star structure, relativity, and, for those located in globular clusters, stellar dynamics and cluster structure. Although about a dozen binary MSPs in the galactic disk now have optical counterparts, and are thus amenable to detailed study, there are no firm identifications in globular star clusters, where distances and reddening are accurately known, and the most interesting dynamical interactions can occur. The optimal cluster to amend this situation is 47 Tucanae, the cluster with the largest number of known MSPs, located nearby, and with minimal reddening. By good fortune, in Cycle 8 an extraordinarily long WFPC2 exposure -- 8 days -- was obtained for this cluster. Although the motivation for that work was very different than that discussed here, namely a search for planetary transits, this unique field is fully the stellar equivalent of the Hubble Deep Field. We propose here to use newly derived, highly precise radio positions for a large number of MSPs in 47 Tuc, together with precision astrometric and photometric tools we have developed in previous HST programs, to greatly increase the number of optically identified MSPs, and provide the first such identifications in globular clusters. ------------------------------------------------------------------------------------ 8742( 1) - 12/30/99 13:01 - [ 2] Summary Form for Proposal 8742 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category AR ------------------------------------------------------------------------------------------------------------------------------------