! +====================+ ! | PED OUTPUT PRODUCT | ! +====================+ ! ! /data/frodo1/aroman/work/6859.prop ! Generated by PREPROCESSOR, version 7.1.1c ! Date: Mon Jul 14 15:40:54 EDT 1997 Proposal_Information Title: STELLAR POPULATIONS IN THE M31 DISK Proposal_Category: GTO/WF2 Scientific_Category: STELLAR POPULATIONS Cycle: 6 Investigators PI_Name: TRAUGER, JOHN PI_Institution: JET PROPULSION LABORATORY CoI_Name: Jon Holtzman CoI_Institution: Lowell Observatory Contact: CoI_Name: Jay Gallagher CoI_Institution: University of Wisconsin Contact: Abstract: We will study the stellar populations in two fields in the disk of M31 using WFPC2. The fields lie at galactocentric radii of ~ 6 and 25 kpc, and were selected to avoid spiral arms and have low, uniform extinction. We will construct color-magnitude diagrams from photometry of individual stars down to V~27, corresponding to M(V)~2.5. The location of the giant branches will be used to infer metallicity gradients in the disk of M31. We will also measure the dispersion in metallicity and look for evidence of bi- or multi- modality. The ability to observe faint will allow us to disentangle the effects of age and metallicity on the location and spread of the giant branch because if younger stars are present, we will see the upper main sequence. In addition, high spatial resolution is required to get sufficiently accurate photometry in the crowded inner disk fields to study giant brach morphology. If an upper main sequence is seen, we will use the observed width of the main sequence to constrain star formation histories over the past ~ 2 Gyr. By comparing the number of main sequence stars to giants, we will estimate the relative fraction of stars formed before and after ~ 2 Gyr ago. We will try to measure the IMF (over a limited mass range) from the observed main sequence luminosity function. These data will put significantly new constraints on theories of spiral galaxy formation, since M31 is the only large spiral galaxy apart from the Milky Way in which we can study individual stars. Questions Observing_Description: We will observe two fields in the disk of M31, located at galactocentric radii of ~ 6 and 25 kpc. The regions were chosen to lie in areas of uniform (and low) obscuration judging from high quality plate material. An orbit of observations in each of F555W and F814W will be made in each field. NICMOS parallels will be obtained. Real_Time_Justification: Calibration_Justification: Additional_Comments: Fixed_Targets Target_Number: 1 Target_Name: M31-INNER Alternate_Names: Description: GALAXY Position: RA=0H 44M 21.82S +/- 0.010S,DEC=41D 44' 54.5" +/- 0.10",PLATE-ID=0738 Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 25 Comments: Target_Number: 2 Target_Name: M31-OUTER Alternate_Names: Description: GALAXY Position: RA=0H 36M 57.30S +/- 0.010S,DEC=39D 51' 59.8" +/- 0.10",PLATE-ID=0738 Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 25 Comments: Solar_System_Targets Generic_Targets Scan_Data Visits Visit_Number: 01 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 10 Target_Name: M31-INNER Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: CR-SPLIT=NO,ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 300 S Special_Requirements: NO SPLIT PAR 22 WITH 10-21 Comments: Exposure_Number: 20 Target_Name: M31-INNER Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1000 S Special_Requirements: SAME POS AS 10 NO SPLIT Comments: Exposure_Number: 21 Target_Name: M31-INNER Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1100 S Special_Requirements: SAME POS AS 10 NO SPLIT Comments: Exposure_Number: 22 Target_Name: M31-INNER Config: NIC2 Opmode: MULTIACCUM Aperture: NIC2-FIX Sp_Element: F110W Wavelength: Optional_Parameters: SAMP-SEQ=SPARS256,NSAMP=12 Number_of_Iterations: 1 Time_Per_Exposure: DEF Special_Requirements: Comments: Exposure_Number: 30 Target_Name: M31-INNER Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: CR-SPLIT=NO,ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 200 S Special_Requirements: SAME POS AS 10 NO SPLIT PAR 42 WITH 30-41 Comments: Exposure_Number: 40 Target_Name: M31-INNER Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1000 S Special_Requirements: SAME POS AS 10 NO SPLIT Comments: Exposure_Number: 41 Target_Name: M31-INNER Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1300 S Special_Requirements: SAME POS AS 10 NO SPLIT Comments: Exposure_Number: 42 Target_Name: M31-INNER Config: NIC2 Opmode: MULTIACCUM Aperture: NIC2-FIX Sp_Element: F160W Wavelength: Optional_Parameters: SAMP-SEQ=SPARS256,NSAMP=12 Number_of_Iterations: 1 Time_Per_Exposure: DEF Special_Requirements: Comments: Visit_Number: 02 Visit_Requirements: ORIENT 0D TO 359D On_Hold_Comments: Visit_Comments: Exposure_Number: 10 Target_Name: M31-OUTER Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: CR-SPLIT=NO,ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 300 S Special_Requirements: NO SPLIT PAR 22 WITH 10-21 Comments: Exposure_Number: 20 Target_Name: M31-OUTER Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1000 S Special_Requirements: SAME POS AS 10 NO SPLIT Comments: Exposure_Number: 21 Target_Name: M31-OUTER Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F555W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1100 S Special_Requirements: SAME POS AS 10 NO SPLIT Comments: Exposure_Number: 22 Target_Name: M31-OUTER Config: NIC2 Opmode: MULTIACCUM Aperture: NIC2-FIX Sp_Element: F110W Wavelength: Optional_Parameters: SAMP-SEQ=SPARS256,NSAMP=12 Number_of_Iterations: 1 Time_Per_Exposure: DEF Special_Requirements: Comments: Exposure_Number: 30 Target_Name: M31-OUTER Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: CR-SPLIT=NO,ATD-GAIN=15 Number_of_Iterations: 1 Time_Per_Exposure: 200 S Special_Requirements: SAME POS AS 10 NO SPLIT PAR 42 WITH 30-41 Comments: Exposure_Number: 40 Target_Name: M31-OUTER Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1000 S Special_Requirements: SAME POS AS 10 NO SPLIT Comments: Exposure_Number: 41 Target_Name: M31-OUTER Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F814W Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1300 S Special_Requirements: SAME POS AS 10 NO SPLIT Comments: Exposure_Number: 42 Target_Name: M31-OUTER Config: NIC2 Opmode: MULTIACCUM Aperture: NIC2-FIX Sp_Element: F160W Wavelength: Optional_Parameters: SAMP-SEQ=SPARS256,NSAMP=12 Number_of_Iterations: 1 Time_Per_Exposure: DEF 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