6788( 4) - 09/12/97 16:27 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6788 Version: 4 Check-in Date: 12-Sep-1997 16:26:55 1.Proposal Title: The Main Sequence Luminosity Function of Palomar 5 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle STELLAR POPULATIONS GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: GRAEME SMITH UNIVERSITY OF CALIFORNIA CoI: Carl Grillmair Caltech/Jet Propulsion Laboratory N ------------------------------------------------------------------------------------ 6. Abstract Palomar 5 appears to represent an extreme in the dynamical evolution of globular clusters. A low mass, large core radius, and a low central concentration suggest that Pal 5 has lost a large fraction of it's initial mass and has expanded as a consequence. If the dynamical evolution of Pal 5 has been dominated by the effects of star loss, then theoretical arguments suggest that the stellar mass function should be deficient in low-mass stars. From a dynamical study of NGC 5466 Pryor et al. concluded that the best fitting King-Michie models for that cluster are those which have a cutoff in the stellar mass function at about 0.4 solar masses. A similar or even more extreme truncation in the Pal 5 mass function is possible. We propose to directly test this conclusion by determining the stellar luminosity function of Pal 5 down to V = 27.0 from WFPC2 F555W and F814W frames. Two fields within Pal 5 will be observed, one located near the cluster center and the other just within the half-light radius. A magnitude of V = 27.0 in Pal 5 corresponds to a stellar mass of about 0.3 solar masses, which is fainter than the predicted truncation mass. ------------------------------------------------------------------------------------ Observations Description ------------------------ Images through the F555W and F814W filters are to be obtained of two fields in Pal 5. Exposures will be accumulated over a period of two orbits through each filter per field. One field will be centered on the center of the cluster, and the other centered just within the half-light radius. Real Time Justification ----------------------- None. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6788( 4) - 09/12/97 16:27 - [ 2] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: ------------------------------------------------------------------------------------ 6788( 4) - 09/12/97 16:27 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PALOMAR5 STELLAR CLUSTER, RA=15H 16M 03.7S, DEC=-0D 06' J2000 V = - SURF(V) = 24.58 GLOBULAR CLUSTER 41", REGION, R=5" 55.0 V = 11.75 E(B-V) = 0.03 Comments: Surf(V) flux corresponds to the central surface brightness in V mag per sq arcsec. V is the integrated apparent V magnitude. 2 PALOMAR5- STELLAR CLUSTER, RA=15H 16M 03.7S, DEC=-0D 09' J2000 V = - SURF(V) = 24.90 OFFCENTER GLOBULAR CLUSTER 1", REGION, R=5" 55.0 Comments: Region near half-light radius. Flux corresponds to V mag per sq arcsec at half-light radius. 6788( 4) - 09/12/97 16:27 - [ 4] Visit: 01 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 PALOMAR5 WFPC2 IMAGE WFALL-F F814W CR-SPLIT=DEF 1 2400.00 END ORBIT IX ------------------------------------------------------------------------------------------------------------------------------------ 2 PALOMAR5 WFPC2 IMAGE WFALL-F F814W CR-SPLIT=DEF 1 2600.00 POSition TARGet +0.500, IX +0.500 END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 3 PALOMAR5 WFPC2 IMAGE WFALL-F F555W CR-SPLIT=DEF 1 2600.00 SAME POSition AS 1 END IX ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 4 PALOMAR5 WFPC2 IMAGE WFALL-F F555W CR-SPLIT=DEF 1 2600.00 POSition TARGet +0.500, IX +0.500 END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 5 PALOMAR5-OF WFPC2 IMAGE WFALL-F F814W CR-SPLIT=DEF 1 2400.00 END ORBIT FCENTER IX ------------------------------------------------------------------------------------------------------------------------------------ 6 PALOMAR5-OF WFPC2 IMAGE WFALL-F F814W CR-SPLIT=DEF 1 2600.00 POSition TARGet +0.500, FCENTER IX +0.500 END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 7 PALOMAR5-OF WFPC2 IMAGE WFALL-F F555W CR-SPLIT=DEF 1 2600.00 SAME POSition AS 5 END FCENTER IX ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 8 PALOMAR5-OF WFPC2 IMAGE WFALL-F F555W CR-SPLIT=DEF 1 2600.00 POSition TARGet +0.500, FCENTER IX +0.500 END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 6788( 4) - 09/12/97 16:27 - [ 5] Summary Form for Proposal 6788 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category STELLAR POPULATIONS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements END ORBIT POSition TARGet +0.500,+0.500 END ORBIT SAME POSition AS 1 END ORBIT SAME POSition AS 5 END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names PALOMAR5 PALOMAR5-OFFCENTER ------------------------------------------------------------------------------------------------------------------------------------