! NOTE: This version revised by Carla Cacciari - 1 May, 1997 ! ! Proposal 6804, submission 1 ! PI: Flavio Fusi Pecci ! Received Mon Feb 19 12:57:34 EST 1996 ! From: dorman@grendel.gsfc.nasa.gov ! +====================+ ! | PED OUTPUT PRODUCT | ! +====================+ ! ! /home/dorman/6804.prop ! Generated by PREPROCESSOR, version 6.0e ! Date: Thu Feb 15 16:40:48 EST 1996 Proposal_Information Title: Large Population Studies of Globular Clusters Proposal_Category: GO Scientific_Category: STELLAR POPULATIONS Cycle: 6 Investigators PI_Name: Flavio Fusi Pecci PI_Institution: Osservatorio Astronomico CoI_Name: Roberto Buonanno CoI_Institution: Osservatorio Astronomico di Roma Contact: N CoI_Name: Carlo Corsi CoI_Institution: Osservatorio Astronomico di Roma Contact: N CoI_Name: Gianni Marconi CoI_Institution: Osservatorio Astronomico di Roma Contact: N CoI_Name: Robert T. Rood CoI_Institution: University of Virginia Contact: N CoI_Name: Ben Dorman CoI_Institution: Goddard Space Flight Center Contact: N CoI_Name: Wayne Landsman CoI_Institution: Goddard Space Flight Center Contact: N CoI_Name: Francesco R. Ferraro CoI_Institution: Osservatorio Astronomico di Bologna Contact: N CoI_Name: Carla Cacciari CoI_Institution: Osservatorio Astronomico di Bologna Contact: N Abstract: We aim at obtaining very accurate photometric data on a complete sample of Post-Main Sequence (PMS) stars over the entire area of the cluster for a sample of ``prototype'' Galactic Globular Cluster (GGCs). During Cycles 4 & 5 we have been granted time to observe the intermediate metal-poor GGC M3 and the very low metallicity GGC M92. To complement these studies of metallicity effects in ``normal'' GGC's, we propose WFPC2 observations (in UV, U, V, I bands) of two ``second parameter'' GGC's, NGC 2808 & NGC 288. The acquisition of a complete sample of PMS stars will allow us to construct Luminosity Functions (LFs) of stars in any PMS phase. LFs are the most powerful observable tools for testing stellar evolutionary models (about the accuracy of the input physics, the reliability of canonical assumptions, etc.) and have a very wide applicability including: (1) the most accurate check of the ``stellar clock'' used in dating globular clusters; (2) a complete survey of very fast evolutionary and rare (trace) stellar types (e.g. UV-bright stars, blue stragglers, binaries) along with their radial distributions, which will provide fundamental information for internal cluster dynamics and for the origin of UV light from elliptical galaxies. Adding \2p\ clusters to our sample will allow us to study possible age variations in the halo and to put \2p\ studies on a more physical basis. NGC 2808 is particularly interesting in that it is probably the best candidate in which to observe a breakdown of the canonical assumptions. Questions Observing_Description: We plan to obtain WFPC2 observations of the Galactic globular clusters NGC 2808 & NGC 288 whose main parameters are listed in the table below. Observations will be taken on the cluster cores in the 3 filters (F336W, F555W, F814W). A far-UV exposure is proposed for NGC 2808 (F160BW). This cluster was observed at 1500 A by UIT on Astro-2 (UIT-2) in March 1995 and shows a dense clump of sources in the center (r < 30") that are too crowded to measure on the ~ 4" resolution UIT image. Neither the ground-based optical photometry nor the UIT photometry is complete at the faint blue end of the HB. Our far-UV image will complement both the UIT-2 image which gives FUV fluxes in the outer cluster, and the mid-UV (F218W) image to be obtained by Djorgovski et al (GO 6095) in Cycle 5. We propose a mid-UV (F255W) image for NGC 288, not previously observed in the ultraviolet, because its HB tail does not extend as blue as that of NGC 2808. Since the primary aim of this program is to obtain accurate photometric measurements for all the evolved stars, the observations have been planned to optimize both the degree of completeness (down to a fixed magnitude limit, even at the very center of the cluster) and the photometric quality of the individual measures. Hence, the adopted exposure times are adequate to reach S/N=30-50 in the V and I filters for a G0V star 2 mag below the turnoff; S/N=20-30 in the U filter for a F0V star at the same magnitude; S/N=20 or more in the mid-UV filter F255W for A0 stars at the TO level; and S/N=20 or more in the far-UV filter F160W for B0 stars at the TO level. The V and I exposures will be divided into sets of sub-exposures short enough to avoid severe blooming from the brightest (V ~ 13) M0 giants, which would introduce some degree of incompleteness and limit accuracy especially in the very crowded central regions. A few very short V and I exposures will also be taken for non-saturated photometry of the brighest part of the CM diagram. This observing sequence will be repeated at radial distance of 2.5 arcmin in NGC 2808. In addition, pairs of very deep V and I exposures will be taken at radial distance of 2.5 arcmin from the cluster center, in order to study the faintest part of the luminosity and mass functions (around absolute luminosity M(V)=+11 and mass M=0.10 Mo), as a function of radial distance. This will provide important information on the structure and dynamics of the cluster. The long exposures will be ``dithered'' on 2-3 positions in order to identify and remove hot pixels and cosmic rays, recover spatial resolution and improve the photometric sampling and accuracy. A very similar observing strategy was applied to the programs GO 5496 (cycle 4) on M3 and 5969 (cycle 5) on M92, of which the present proposal is a natural continuation. The exposure times have been estimated using our own exposure time calculator based on the WFPC2 1995 Handbook, since the ETC provided by the STScI on WWW gave systematically underestimated exposure times. Some basic parameters for the program clusters are listed in Table 1. Table 1. Globular Cluster Parameters. Object Vo(TO) Fe/H E(B-V) log(Rho) NGC2808 19.0 -1.37 0.24 4.6 NGC 288 18.6 -1.40 0.03 1.8 Real_Time_Justification: None. Calibration_Justification: Additional_Comments: Fixed_Targets Target_Number: 1 Target_Name: NGC2808 Alternate_Names: Description: STELLAR CLUSTER,GLOBULAR CLUSTER, Position: RA=09H 12M 02.6S +/- 0.1S,DEC=-64D 51' 47.0" +/- 1" Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: SURF(V) = 15.17+/-0.1 B-V = 0.90 E(B-V) = 0.24 Comments: Above flux values refer to the integrated cluster, for ACQ purposes only. For individual stars see Observing Description Target_Number: 2 Target_Name: NGC288 Alternate_Names: Description: STELLAR CLUSTER,GLOBULAR CLUSTER, Position: RA=00H 52M 47.5S +/- 0.1S,DEC=-26D 35' 24.0" +/- 1" Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: SURF(V) = 20.00+/-0.1 B-V = 0.66 E(B-V) = 0.03 Comments: Above flux values refer to the integrated cluster, for ACQ purposes only. For individual stars see Observing Description Solar_System_Targets Generic_Targets Scan_Data Visits Visit_Number: 01 Visit_Requirements: CVZ On_Hold_Comments: Visit_Comments: no unused visibility should be left at the end of this visit; visit 2 should be scheduled immediately after visit 1 and use the leftover time, so that visit 1 and 2 fit into a total of 6 CVZ orbits. These are all CVZ orbits and parts of the same set of observations, pointing on two positions of the cluster offset by 150'' Exposure_Number: 1 Target_Name: NGC2808 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F336W Wavelength: Optional_Parameters: CR-SPLIT=NO,ATD-GAIN=15,DITHER-TYPE=BOX Number_of_Iterations: 1 Time_Per_Exposure: 1600S Special_Requirements: Comments: Exposure_Number: 3 Target_Name: NGC2808 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: ATD-GAIN=15,DITHER-TYPE=LINE,DITHER-LINE-STEPS=3 Number_of_Iterations: 1 Time_Per_Exposure: 100S Special_Requirements: Comments: Exposure_Number: 5 Target_Name: NGC2808 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: ATD-GAIN=15,DITHER-TYPE=LINE,DITHER-LINE-STEPS=3 Number_of_Iterations: 1 Time_Per_Exposure: 120S Special_Requirements: Comments: Exposure_Number: 7 Target_Name: NGC2808 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: ATD-GAIN=15,CR-SPLIT=0.50 Number_of_Iterations: 1 Time_Per_Exposure: 6S Special_Requirements: MAX DUR Comments: Exposure_Number: 8 Target_Name: NGC2808 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: ATD-GAIN=15,CR-SPLIT=0.50 Number_of_Iterations: 1 Time_Per_Exposure: 14S Special_Requirements: MAX DUR Comments: Exposure_Number: 9 Target_Name: NGC2808 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F160BW Wavelength: Optional_Parameters: CR-SPLIT=NO,DITHER-TYPE=LINE,DITHER-LINE-STEPS=3 Number_of_Iterations: 1 Time_Per_Exposure: 1200S Special_Requirements: Comments: Visit_Number: 02 Visit_Requirements: CVZ;SAME ORIENT AS 1;SEQ 1-2 WITHIN 100M On_Hold_Comments: Visit_Comments: This visit should be scheduled contiguously and immediately after visit 1, without leaving any unused visibility at the end of visit 1. Visit 1 and 2 should fit into a total of 6 CVZ orbits. These are all part of the same set of observations, on two different pointings of the cluster offset by 150"; visit 2 was introduced to allow for GS ACQ, because of the large offset in the POS TARG Special Requirement Exposure_Number: 11 Target_Name: NGC2808 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F336W Wavelength: Optional_Parameters: CR-SPLIT=NO,ATD-GAIN=15,DITHER-TYPE=BOX Number_of_Iterations: 1 Time_Per_Exposure: 1600S Special_Requirements: POS TARG 150.00,150.00 Comments: Exposure_Number: 13 Target_Name: NGC2808 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: ATD-GAIN=15,DITHER-TYPE=LINE,DITHER-LINE-STEPS=3 Number_of_Iterations: 1 Time_Per_Exposure: 100S Special_Requirements: POS TARG 150.00,150.00 Comments: Exposure_Number: 15 Target_Name: NGC2808 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: ATD-GAIN=15,DITHER-TYPE=LINE,DITHER-LINE-STEPS=3 Number_of_Iterations: 1 Time_Per_Exposure: 120S Special_Requirements: POS TARG 150.00,150.00 Comments: Exposure_Number: 17 Target_Name: NGC2808 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: ATD-GAIN=15,CR-SPLIT=0.50 Number_of_Iterations: 1 Time_Per_Exposure: 6S Special_Requirements: SAME POS AS 15 MAX DUR Comments: Exposure_Number: 18 Target_Name: NGC2808 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: ATD-GAIN=15,CR-SPLIT=0.50 Number_of_Iterations: 1 Time_Per_Exposure: 14S Special_Requirements: SAME POS AS 15 MAX DUR Comments: Exposure_Number: 21 Target_Name: NGC2808 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: CR-SPLIT=NO,DITHER-TYPE=BOX Number_of_Iterations: 1 Time_Per_Exposure: 700S Special_Requirements: POS TARG 150.00,150.00 Comments: Exposure_Number: 23 Target_Name: NGC2808 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: CR-SPLIT=NO,DITHER-TYPE=BOX Number_of_Iterations: 1 Time_Per_Exposure: 900S Special_Requirements: POS TARG 150.00,150.00 Comments: Visit_Number: 03 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 04 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F336W Wavelength: Optional_Parameters: ATD-GAIN=15,CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 60S Special_Requirements: Comments: Exposure_Number: 06 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F336W Wavelength: Optional_Parameters: ATD-GAIN=15,CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1000S Special_Requirements: Comments: Exposure_Number: 08 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 2.3S Special_Requirements: MAX DUR Comments: Exposure_Number: 10 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 100S Special_Requirements: Comments: Exposure_Number: 12 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: ATD-GAIN=15, CR-SPLIT=0.5 Number_of_Iterations: 1 Time_Per_Exposure: 28S Special_Requirements: Comments: Exposure_Number: 13 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 1.2S Special_Requirements: MAX DUR 100% Comments: Exposure_Number: 14 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: ATD-GAIN=15, CR-SPLIT=0.5 Number_of_Iterations: 1 Time_Per_Exposure: 24S Special_Requirements: Comments: Exposure_Number: 16 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 140S Special_Requirements: Comments: Exposure_Number: 19 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 140S Special_Requirements: POS TARG 0.3535,0.3535 Comments: Exposure_Number: 24 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 100S Special_Requirements: SAME POS AS 19 Comments: Exposure_Number: 27 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F336W Wavelength: Optional_Parameters: ATD-GAIN=15,CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1000S Special_Requirements: SAME POS AS 19 Comments: Exposure_Number: 29 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F255W Wavelength: Optional_Parameters: ATD-GAIN=7,CR-SPLIT=0.5,CR-TOLERANCE=0.0 Number_of_Iterations: 1 Time_Per_Exposure: 700S Special_Requirements: SAME POS AS 19 Comments: Exposure_Number: 30 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 2 Time_Per_Exposure: 100S Special_Requirements: POS TARG 0.707,0.707 Comments: Exposure_Number: 31 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F336W Wavelength: Optional_Parameters: ATD-GAIN=15,CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1700S Special_Requirements: SAME POS AS 30 Comments: Exposure_Number: 38 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 2 Time_Per_Exposure: 140S Special_Requirements: SAME POS AS 30 Comments: ! !=========================================================================== !======================= SECOND POINTING ============================== !=========================================================================== ! Visit_Number: 04 Visit_Requirements: SAME ORIENT AS 3; GROUP 3-4 WITHIN 1D On_Hold_Comments: Visit_Comments: Repointing at exposure 100 designed to avoid guide star reacquisition during orbit 3. Please inform investigators if GSREACQ is in fact necessary. This has been now superseded by breaking with a new visit for exposures 100 and following. Exposure_Number: 100 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 230S Special_Requirements: POS TARG 110,0 Comments: Exposure_Number: 101 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 40S Special_Requirements: SAME POS AS 100 Comments: Exposure_Number: 102 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 40S Special_Requirements: SAME POS AS 100 Comments: Exposure_Number: 103 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 160S Special_Requirements: SAME POS AS 100 Comments: Exposure_Number: 104 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 160S Special_Requirements: POS TARG 110.3535,0.3535 Comments: Exposure_Number: 106 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 230S Special_Requirements: SAME POS AS 104 Comments: Exposure_Number: 108 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 200S Special_Requirements: POS TARG 110.7070,0.7070 Comments: Exposure_Number: 110 Target_Name: NGC288 Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 160S Special_Requirements: SAME POS AS 108 Comments: Data_Distribution ! 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