! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template ! ID: 6438 ! ! Refer to the HST Phase II Proposal Instructions to fill this out ! Anything after a "!" is ignored, and may be deleted ! All keywords with multiple entries are comma delimited except the ! Visit_Requirements and Special_Requirements keywords which can be ! delimited with carriage returns or semi-colons, but not commas ! ! For help call your Program Coordinator: Mutchler ! Phone: 410-338-1321 , E-mail: mutchler@stsci.edu ! Proposal_Information ! Section 4 Title: DUST STRUCTURE IN BACKLIT GALAXIES Proposal_Category: GO Scientific_Category: GALAXIES & CLUSTERS Cycle: 6 Investigators PI_name: William Keel PI_Institution: University of Alabama CoI_Name: Raymond White,III CoI_Institution: University of Alabama Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) Pairs of overlapping galaxies offer an unusually direct way to measure the extinction within the disk of spiral galaxies, which has implications for M/L ratios, star-formation histories, and the role of galaxy obscuration in statistics of high-redshift objects. Ground-based data have allowed us to measure the extinction in several backlit spirals, as averaged over regions of hundreds of parsecs. WFPC2 imaging of three of our best candidates in B and I bands will allow us to measure the dust clumping on finer scales than possible from the ground, and to establish whether the relatively flat reddening curves we have found are indeed the product of clumping. Together with scheduled ISO observations, we should be able to establish the clumping spectrum of dust over a very wide range of scales, which is crucial to modelling the effects of dust on the emergent radiation from spiral galaxies. Questions ! Free format text (please update) Observing_Description: Each pair fits comfortably within the WFPC2 field, and the overlap region always fits on a single chip. We place these regions on WF3 to keep the surface-brightness sensitivity of larger pixels than in PC1, and to include as much of the surrounding galaxy pair as possible. We select passbands which give a long wavelength baseline and avoid strong emission lines, as was done with B and I bands for the ground -based observations. For the WFPC2, F450W and F814W were chosen for their appropriate locations and wide bandwidths (in the interest of throughput). Exposure-time estimates use the mean measured surface brightness in B and I in the overlap regions, known from ground-based observations. All the regions are well within the B=25 per square arcsecond isophote, with B surface brightness typically 23.5-24 per square arcsecond (1-1.5 scale lengths inside the reference isophote). We expect S/N ratio of ~ 7 (or better) per pixel so we can be sure of detecting even marginally resolved clouds of high optical depth (i.e. optically thick covering only a fraction of a single pixel). CR splits are especially important to avoid losing dust features under a cosmic ray. Using the WFPC2 sensitivity and filter curves from the instrument manual, we need typically 45 minutes total in F450W and 25 minutes in F814W (in practice two orbits per target). AM1316-241 and AM0500-620 have reasonably symmetric spirals in front of well-behaved elliptical galaxies, and are both in our ISO target lists. NGC 3314 is an almost perfect superposition of an Sc galaxy in front of an Sb, giving a unique chance to trace dust in the inner parts of a spiral now that we can interplate its structure guided by a K ground -based image. We note that one of our best target pairs, AM0500-620, spends substantial time in the continuous-viewing zone, so that opportunities for improved efficiency may exist (though we do not require CVZ time for scientific reasons). Real_Time_Justification: Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: NGC3314 Alternate_Names: Description: GALAXY, CLUSTER OF GALAXIES, GALAXY PAIR Position: RA=10H 37M 13.14S +/-0.04S, DEC=-27D 41' 05.9" +/-0.5", PLATE-ID=00GU Equinox: 2000 RV_or_Z: V=2763 RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: V=13.5 +/- 0.5 SURF(B)=24.0 +/- 0.5 ! Include at least V and B-V Comments: Overlapping (noninteracting) galaxy pair in Abell 1060; orientation restrictions are to keep a 13.5-mag GSC star off WF3 and on WF2 or WF4 for scattered-light control. Target_Number: 2 Target_Name: AM1316-241 Alternate_Names: Description: GALAXY, INTERACTING GALAXY, SPIRAL, ELLIPTICAL Position: RA=13H 19M 32.31S +/- 0.16S, DEC=-24D 29' 10.2" +/- 2.0", PLATE-ID=02J5 Equinox: 2000 RV_or_Z: V=9700 RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: V=15.0 +/- 0.5 SURF(B)=24.0 +/- 0.5 ! Include at least V and B-V Comments: Overlapping spiral/elliptical galaxy pair; orientation restrictions are to avoid the outer end of the spiral falling on PC1 and losing surface-brightness sensitivity (the outer edge of the elliptical would be acceptable on PC1). Target_Number: 3 Target_Name: AM0500-620 Alternate_Names: Description: GALAXY, INTERACTING GALAXY, SPIRAL, ELLIPTICAL Position: RA=05H 00M 34.11S +/-0.28S, DEC=-62D 04' 08.0" +/- 2.0", PLATE-ID=00MU Equinox: 2000 RV_or_Z: RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: V=15.5+/- 0.5 SURF(B)=24.5+/-0.5 ! Include at least V and B-V Comments: Overlapping spiral/elliptical galaxy pair ! This is a template for a single visit containing a single exposure ! Repeat exposure and visit blocks as needed Visits ! Section 6 ! Visit_Number: 1 ! Visit_Requirements: ORIENTation 350D TO 40D ! Visit_Comments: Schedule either visit 1 or 2 (multiple orient ranges acceptable) ! ! Exposure_Number: 1 ! Section 6.5 ! Target_Name: NGC3314 ! Config: WFPC2 ! Opmode: IMAGE ! Aperture: WF3-FIX ! Sp_Element: F450W ! Wavelength: ! Optional_Parameters: !Number_of_Iterations: 1 ! Time_Per_Exposure: 120S !Special_Requirements: ! Section 7.2 ! ! Exposure_Number: 2 ! Section 6.5 ! Target_Name: NGC3314 ! Config: WFPC2 ! Opmode: IMAGE ! Aperture: WF3-FIX ! Sp_Element: F814W ! Wavelength: ! Optional_Parameters: !Number_of_Iterations: 1 ! Time_Per_Exposure: 60S !Special_Requirements: ! Section 7.2 ! ! Exposure_Number: 3 ! Section 6.5 ! Target_Name: NGC3314 ! Config: WFPC2 ! Opmode: IMAGE ! Aperture: WF3-FIX ! Sp_Element: F814W ! Wavelength: ! Optional_Parameters: !Number_of_Iterations: 1 ! Time_Per_Exposure: 2000S ! !Special_Requirements: ! Section 7.2 ! Exposure_Number: 4 ! Section 6.5 ! Target_Name: NGC3314 ! Config: WFPC2 ! Opmode: IMAGE ! Aperture: WF3-FIX ! Sp_Element: F450W ! Wavelength: ! Optional_Parameters: !Number_of_Iterations: 1 ! Time_Per_Exposure: 2600S !Special_Requirements: END ORBIT Visit_Number: 2 Visit_Requirements: ORIENTation 260D TO 310D Visit_Comments: If visit 2 becomes difficult to schedule, then uncomment visit 1 in RPS2 file and use it instead (two orient ranges acceptable) Exposure_Number: 1 ! Section 6.5 Target_Name: NGC3314 Config: WFPC2 Opmode: IMAGE Aperture: WF3-FIX Sp_Element: F450W Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 120S Special_Requirements: ! Section 7.2 Exposure_Number: 2 ! Section 6.5 Target_Name: NGC3314 Config: WFPC2 Opmode: IMAGE Aperture: WF3-FIX Sp_Element: F814W Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 60S Special_Requirements: ! Section 7.2 Exposure_Number: 3 ! Section 6.5 Target_Name: NGC3314 Config: WFPC2 Opmode: IMAGE Aperture: WF3-FIX Sp_Element: F814W Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2000S Special_Requirements: ! Section 7.2 Exposure_Number: 4 ! Section 6.5 Target_Name: NGC3314 Config: WFPC2 Opmode: IMAGE Aperture: WF3-FIX Sp_Element: F450W Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2600S Special_Requirements: ! Section 7.2 END ORBIT Visit_Number: 3 Visit_Requirements: ! Section 7.1 Orientation 193D to 103D Exposure_Number: 1 ! Section 6.5 Target_Name: AM1316-241 Config: WFPC2 Opmode: IMAGE Aperture: WF3-FIX Sp_Element: F450W Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 120S Special_Requirements: ! Section 7.2 POS TARG +10.0,+10.0 Exposure_Number: 2 ! Section 6.5 Target_Name: AM1316-241 Config: WFPC2 Opmode: IMAGE Aperture: WF3-FIX Sp_Element: F814W Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 60S Special_Requirements: ! Section 7.2 SAME POS AS 1 Exposure_Number: 3 ! Section 6.5 Target_Name: AM1316-241 Config: WFPC2 Opmode: IMAGE Aperture: WF3-FIX Sp_Element: F814W Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2000S Special_Requirements: ! Section 7.2 SAME POS AS 1 Exposure_Number: 4 ! Section 6.5 Target_Name: AM1316-241 Config: WFPC2 Opmode: IMAGE Aperture: WF3-FIX Sp_Element: F450W Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2600S Special_Requirements: ! Section 7.2 SAME POS AS 1 END ORBIT Visit_Number: 4 Visit_Requirements: ! Section 7.1 Exposure_Number: 1 ! Section 6.5 Target_Name: AM0500-620 Config: WFPC2 Opmode: IMAGE Aperture: WF3-FIX Sp_Element: F450W Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 120S Special_Requirements: ! Section 7.2 Exposure_Number: 2 ! Section 6.5 Target_Name: AM0500-620 Config: WFPC2 Opmode: IMAGE Aperture: WF3-FIX Sp_Element: F814W Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 60S Special_Requirements: ! Section 7.2 Exposure_Number: 3 ! Section 6.5 Target_Name: AM0500-620 Config: WFPC2 Opmode: IMAGE Aperture: WF3-FIX Sp_Element: F814W Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2000S Special_Requirements: ! Section 7.2 Exposure_Number: 4 ! Section 6.5 Target_Name: AM0500-620 Config: WFPC2 Opmode: IMAGE Aperture: WF3-FIX Sp_Element: F450W Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2600S Special_Requirements: ! Section 7.2 END ORBIT Data_Distribution ! Defaults indicated; change if desired Medium: 8MM ! 8MM or 6250BPI or 1600BPI Blocking_Factor: 10 ! 10 or 1 ! Only astronomers with very old 9- ! track tape drives should consider ! a blocking factor of 1 Ship_To: PI_Address ! STSCI or PI_Address or ! PI Address from Phase I is: ! ! Department of Physics and Astro ! nomy ! Box 870324 ! Tuscaloosa ! 35487 ! ! Ship_Via: UPS ! UPS (2-day) or OVERNIGHT ! Overnight shipping done at PI expense Recipient_Email: ! Needed if Ship_To: is not PI_Address ! ! Let us know what you think of this template and software! ! Please send a list of your likes and dislikes to your Program Coordinator