! +====================+ ! | PED OUTPUT PRODUCT | ! +====================+ ! ! /clotho/data1/pi54/6646.prop ! Generated by PREPROCESSOR, version 6.0e ! Date: Wed Feb 14 09:49:24 EST 1996 Proposal_Information Title: WFPC2 Imaging of Dwarf Spirals Proposal_Category: GO Scientific_Category: STELLAR POPULATIONS Cycle: 6 Investigators PI_Name: James Schombert PI_Institution: NASA Headquarters CoI_Name: Rachel Pildis CoI_Institution: Harvard-Smithsonian Center for Astrophysics Contact: CoI_Name: Jo Ann Eder CoI_Institution: Arecibo Observatory Contact: CoI_Name: Augustus Oemler CoI_Institution: Observatories of the Carnegie Inst of Washingtion Contact: Abstract: This project proposes to obtain UV and blue WFPC2 images of a new class of galaxies: dwarf spirals. As with most low surface brightness (LSB) galaxies, dwarf spirals have the conflicting properties of very blue mean colors with little evidence of current or past star formation. We propose to resolve, or at least better define, this dilemma with WFPC2 imaging to investigate the nature and extent of the hot component of the stellar population in dwarf spirals. As a newly discovered class of galaxies, very little is known of their origin or evolution. Nothing is known of their UV properties. Their low contrast to the night sky makes them excellent candidates for space imaging. Questions Observing_Description: We propose three filter imaging of 5 targets. The filters we have selected are F255W, F336W (Johnson U) and F439W (Johnson B). To achieve our science goals we require the maximum S/N in the B filter for structure analysis (surface brightness profiles) and sufficient, but lesser S/N in filters F225W and F336W for areal (box) photometry. To achieve a depth of 23 B mag arcsec^-2 (the typical central surface brightness of our dwarfs) with a S/N of 2 per pixel will require approximately 2000 secs. The outer regions of these dwarfs will drop to 30 B mags arcsec^-2; however, there will be thousands of pixels to integrate over for surface photometric information. Although the throughput on the WFPC2 drops for the F225W and F336W regions, the night sky becomes even darker and we anticipate similar exposure times for those filters to achieve reasonable S/N for 2D color analysis. Our observing plan is to break the each orbit up into 4 exposures of 9 mins. Four exposures of 9 mins with 3 mins of overhead and 7 mins of guide star acquisition implies 52 mins of observation (last overhead is during Earth occultation). At the latitudes of these galaxies (all in the Arecibo declination range of 10 to 25), a HST orbit has 53 mins of useful observing. Each filter requires one orbit, thus, 5 objects through 3 filters requires 15 orbits. Our objects were selected for the highest elevation above the ecliptic plane; however, we have selected targets based primarily on their astrophysical interest, and only secondarily on their elevation angle. We request NO CR-SPLIT mode to reduce the overhead since the multiple frames per orbit will suffice for cosmic ray elimination. Real_Time_Justification: None. Calibration_Justification: Additional_Comments: Fixed_Targets Target_Number: 1 Target_Name: D564-15 Alternate_Names: Description: GALAXY,LOW SURFACE BRIGHTNESS,SPIRAL, Position: RA=9H 11M 17.99S +/- 1.0", DEC=17D 10' 6.1" +/- 1.0", ! PLATE-ID=01G6 Equinox: J2000. RV_or_Z: V = 3265 RA_PM: 0.0 Dec_PM: 0.0 Epoch: J2000. Annual_Parallax: 0.0 Flux: V = 16.5+/-0.5 SURF(V) = 25.2+/-0.5 Comments: Target_Number: 2 Target_Name: D721-5 Alternate_Names: Description: GALAXY,LOW SURFACE BRIGHTNESS,SPIRAL, Position: RA=14H 2M 43.7S +/- 1.0", DEC=9D 59' 28.8" +/- 1.0", ! PLATE-ID=01US Equinox: J2000. RV_or_Z: V = 5795 RA_PM: 0.0 Dec_PM: 0.0 Epoch: J2000. Annual_Parallax: 0.0 Flux: V = 17.3+/-.5 SURF(V) = 24.8+/-.5 Comments: Target_Number: 3 Target_Name: D774-1 Alternate_Names: Description: GALAXY,LOW SURFACE BRIGHTNESS,SPIRAL, Position: RA=7H 49M 40.8S +/- 1.0", DEC=6D 36' 36.3" +/- 1.0", ! PLATE-ID=02V4 Equinox: J2000. RV_or_Z: V = 4793 RA_PM: 0.0 Dec_PM: 0.0 Epoch: J2000. Annual_Parallax: 0.0 Flux: V = 14.79+/-0.5 SURF(V) = 24.1+/-0.5 Comments: Solar_System_Targets Generic_Targets Scan_Data Visits Visit_Number: 01 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 1 Target_Name: D774-1 Config: WFPC2 Opmode: IMAGE Aperture: WF3 Sp_Element: F255W Wavelength: Optional_Parameters: CR-SPLIT=0.,DITHER-TYPE=LINE,DITHER-LINE-STEPS=3 Number_of_Iterations: 1 Time_Per_Exposure: 600S Special_Requirements: SEQ 1 NON-INT; LOW-SKY Comments: Exposure_Number: 2 Target_Name: D774-1 Config: WFPC2 Opmode: IMAGE Aperture: WF3 Sp_Element: F336W Wavelength: Optional_Parameters: CR-SPLIT=0.,DITHER-TYPE=LINE,DITHER-LINE-STEPS=3 Number_of_Iterations: 1 Time_Per_Exposure: 600S Special_Requirements: LOW-SKY Comments: Exposure_Number: 3 Target_Name: D774-1 Config: WFPC2 Opmode: IMAGE Aperture: WF3 Sp_Element: F439W Wavelength: Optional_Parameters: CR-SPLIT=0.,DITHER-TYPE=LINE,DITHER-LINE-STEPS=3 Number_of_Iterations: 1 Time_Per_Exposure: 600S Special_Requirements: LOW-SKY Comments: Visit_Number: 02 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 1 Target_Name: D564-15 Config: WFPC2 Opmode: IMAGE Aperture: WF3 Sp_Element: F255W Wavelength: Optional_Parameters: CR-SPLIT=0.,DITHER-TYPE=LINE,DITHER-LINE-STEPS=3 Number_of_Iterations: 1 Time_Per_Exposure: 600S Special_Requirements: LOW-SKY Comments: Exposure_Number: 2 Target_Name: D564-15 Config: WFPC2 Opmode: IMAGE Aperture: WF3 Sp_Element: F336W Wavelength: Optional_Parameters: CR-SPLIT=0.,DITHER-TYPE=LINE,DITHER-LINE-STEPS=3 Number_of_Iterations: 1 Time_Per_Exposure: 600S Special_Requirements: LOW-SKY Comments: Exposure_Number: 3 Target_Name: D564-15 Config: WFPC2 Opmode: IMAGE Aperture: WF3 Sp_Element: F439W Wavelength: Optional_Parameters: CR-SPLIT=0.,DITHER-TYPE=LINE,DITHER-LINE-STEPS=3 Number_of_Iterations: 1 Time_Per_Exposure: 600S Special_Requirements: LOW-SKY Comments: Visit_Number: 03 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 1 Target_Name: D721-5 Config: WFPC2 Opmode: IMAGE Aperture: WF3 Sp_Element: F255W Wavelength: Optional_Parameters: CR-SPLIT=0.,DITHER-TYPE=LINE,DITHER-LINE-STEPS=3 Number_of_Iterations: 1 Time_Per_Exposure: 600S Special_Requirements: SEQ 1 NON-INT; LOW-SKY Comments: Exposure_Number: 2 Target_Name: D721-5 Config: WFPC2 Opmode: IMAGE Aperture: WF3 Sp_Element: F336W Wavelength: Optional_Parameters: CR-SPLIT=0.,DITHER-TYPE=LINE,DITHER-LINE-STEPS=3 Number_of_Iterations: 1 Time_Per_Exposure: 600S Special_Requirements: LOW-SKY Comments: Exposure_Number: 3 Target_Name: D721-5 Config: WFPC2 Opmode: IMAGE Aperture: WF3 Sp_Element: F439W Wavelength: Optional_Parameters: CR-SPLIT=0.,DITHER-TYPE=LINE,DITHER-LINE-STEPS=3 Number_of_Iterations: 1 Time_Per_Exposure: 600S Special_Requirements: LOW-SKY Comments: Data_Distribution ! 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