11279( 1) - 03/30/07 11:25 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11279 Version: 1 Check-in Time: 30-Mar-2007 15:25:41 STScI Edit Number: 0 Title A Legacy Archive PSF Library And Circumstellar Environments (LAPLACE) Investigation ------------------------------------------------------------------------------------ Type Cycle Parallel Pointing Tolerance AR 16 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Glenn Schneider University of Arizona CoI: Dr. Murray Silverstone University of Arizona N CoI: Dr. Dean C. Hines Space Science Institute N CoI: Dr. Joseph Rhee University of California - Los Angeles N 11279( 1) - 03/30/07 11:25 - [ 2] ------------------------------------------------------------------------------------ Abstract NICMOS coronagraphy, with well-matched template Point Spread Function (PSF) subtraction, probes the closest environments of occulted targets with the highest imaging sensitivity in intrinsically high contrast fields at the smallest radial distances afforded, uniquely, by HST. NICMOS PSF-subtracted coronagraphy has been invoked in a wide variety of HST programs with science themes as divergent as detecting and characterizing disks of circumstellar material in neo-natal stellar environments, to studying faint nebulosity associated with luminous active galaxies, to searching for planetary-mass companions in extrasolar planetary systems recently born and in the "stellar graveyard." The investment in HST time in the execution of these and other programs, which has resulted in more than 8450 NICMOS coronagraphic images to date, has met with mixed returns. Stunning (but infrequent) successes, importantly advancing their fields highlight much more frequent, unfortunately common, failures arising from highly compromised technically-achievable performance due to the lack of suitable template PSFs required to produce high-fidelity, photometrically robust, high contrast coronagraphic images. We propose to remedy this situation by undertaking a rigorous, homogeneous, and complete recalibration and analysis of the full archival set of raw NICMOS coronagraphic images previously obtained and residing in the MAST to create a Legacy library of template PSFs enabling the recovery of the large body of science otherwise lost. This PSF library, along with generically applicable analysis software that we will deliver to STScI, will: (1) critically augment the needs of future observational programs reliant on high-fidelity PSF subtractions, (2) increase their yields and photometric efficacy, (3) reduce the observing time (HST orbit allocations) otherwise required for near- contemporaneous reference PSF observations, and (4) greatly enrich the yet- unrealized potential of the many NICMOS coronagraphic observations already acquired from the broad spectrum of science programs previously executed. We will then use the enabling power of the PSF library to re-reduce and re-analyze all archival NICMOS coronagraphic observations of circumstellar disk and VLM stellar, brown dwarf, and EJP companion candidate stars (~ 400 targets) to probe for previously undetected circumstellar disks. Through image analysis and modeling we will ascertain the physical properties of newly-discovered disks and their constituent grains. With a very large and homogeneously contrast-limited sample of optimally PSF-subtracted images, we will also set spatially resolved dust-scattered light flux density limits from non-detections to constrain the properties of the many IR-excess (and other) sources in this sample. ------------------------------------------------------------------------------------