8242( 5) - 02/28/00 11:41 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8242 Version: 5 Check-in Date: 28-Feb-2000 11:40:18 1.Proposal Title: WFPC2 Imaging of Dust Structures and Star Formation in the Disk-Halo Interface of Spiral Galaxies ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Blair Savage University of Wisconsin - Madison CoI: Mr. J. Christopher Howk Univ. of Wisconsin/Johns Hopkins Univ. Y ------------------------------------------------------------------------------------ 5. Abstract WFPC2 images of five edge-on spirals to study star formation and dusty interstellar clouds in the disk-halo interface of these galaxies. Ground-based and HST images of the nearby (9 Mpc) edge-on spiral NGC 891 show an unexpected web of hundreds of dust structures at heights 0.4 <= z <= 1.7 kpc (Howk & Savage 1997). With masses >10^5- 10^6 M(sun), the more prominent extraplanar dust complexes may be sites of star formation at high-z, and there is evidence for H II regions associated with unresolved continuum sources far above the plane of NGC 891. We have established that such high-z dust features and H II regions are not unique to NGC 891. We propose to image five edge-on spiral galaxies (D ~ 17 - 70 Mpc) with the WFPC2. The proposed BVI images will be used to identify sites of on- going star formation in the thick disks of these galaxies, all of which show evidence for high-z dust complexes, and with ground-based H Alpha images will be used to study the stellar content o f any such regions. The resolution and point-source sensitivity of the WFPC2 are crucial for studying these star-forming regions. We will also use these images to study interstellar matter in the thick disks of these galaxies with unprecedented detail and derive the fundamental properties of high-z dusty clouds-- including sizes, extinctions, column densities, masses, and gravitational potential energies. ------------------------------------------------------------------------------------ 8242( 5) - 02/28/00 11:41 - [ 2] Observations Description ------------------------ We will obtain broadband images in the F450W, F555W, and F814W filters (equivalent to BVI) of five edge-on galaxies. The properties of these galaxies are summarized in Table 1. These galaxies were chosen because they are known to have inclinations from the plane of the sky i>~88degrees from test images taken with the WIYN 3.5-m telescope (or quality published images in the case of NGC 5777), and the WIYN 0.7arcsec images for these galaxies all show evidence for absorbing dust structures at large distances from the midplane. The linear resolution of the WFPC2 at the distances of each of these galaxies is given in the last column of Table 1. Images in three filters are needed to allow us to solve for the absorbing properties of these clouds (e.g., HS). Three filters are also needed to account for the reddening of any high-z OB associations, a necessary step for deriving accurate absolute magnitudes and colors. The F450W filter has been chosen for the ``B-band'' instead of the narrower F439W filter because of the higher throughput. We note that the transformation between the F450W filter and the B-band of the standard system is quite well behaved (Holtzman Etal 1995). Visibility times for our targets range from 52 to 56 minutes per orbit, with guide star acquisitions requiring 6 minutes. Additional WFPC2 overhead times are ~5 minutes with 2-exposure CR-SPLITS. The exposure times requested should allow us to observe objects to m_V > 26.0 (S/N>=10) in all filters (which applies for spectral types O5-A0). This allows us to study objects like the high-z regions in NGC 891, which have M_V~-7, to distances <=40 and <=80 Mpc with S/N>=10 and >= 5, respectively. At z -heights of ~1.5 kpc, typical surface brightnesses of edge-on galaxies are of order Sigma_R ~ 21 mag/arcsec^2 at one radial scale-length, with this value falling to Sigma_R ~ 22 mag/arcsec^2 by z ~ 3.5 kpc (e.g., van der Kruit & Searle 1982 for NGC 4013 and NGC 4217 and others). Usi ng these rough values, exposure times were estimated using the on-line exposure time calculations for a spectrum characteristic of Sb galaxies. For total exposure times of >~ 4800 sec (2 orbits) with the F450W filter, and >~ 2400 sec (1 orbit) in each of the F555W and F814W filters, we will obtain S/N~ 14 and 7 per pixel at heights z~ 1.5 and 3 kpc, respectively, from the midplanes of these galaxies. These signal-to- noise ratios should be sufficient for studying high-z dust structures in these galaxies. Table 1: Target Edge-On Galaxies: Object & Hubble & B_T & 10^40 L_FIR/D_25^2 & v_r & Dist. & Res. & V_M_V=-7 & Type & (mag) & (ergs s^-1 kpc^-2 ) & (kms) & (Mpc) & (pc) & (mag) , NGC 4013 & Sb & 12.2 & 2.6 & 835 & 17 & 8 & 24.2 , NGC 4217 & Sb & 12.0 & <0.12 & 1026 & 17 & 8 & 24.2 , NGC 4302 & Sc & 12.5 & <=2.3 & 1149 & 17 & 8 & 24.2 , UGC 4277 & Sbc &14.9 & ... & 5500 & 73: & 35 & 27.3 , NGC 5777 & Sb & 14.2 & ... & 2142 & 29: & 14 & 25.3 , Real Time Justification ----------------------- We will obtain deep H Alpha emission line images of all of the galaxies in our sample with the WIYN 3.5-m telescope on Kitt Peak. WIYN provides excellent image quality. In our experience WIYN is able to consistently yield images with 0.6 to 0.8 arcsec (FWHM) seeing over long integrations. While these data will not be able to match the WFPC2 images in resolution, they will be important for identifying areas of active star formation through the associated extraplanar H Alpha emission, and for finding high-z H II regions. Calibration Justification ------------------------- Real_Time_Justification Additional Comments ------------------- ------------------------------------------------------------------------------------ 8242( 5) - 02/28/00 11:41 - [ 3] Data Distribution Paper Products: YES Media: ELECTRONIC Blocking Factor: 10 Ship To: J. Christopher Howk, Dept. of Phys. & Ast., Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218 Ship Via: Email: howk@pha.jhu.edu----------------------------------------- ------------------------------------------------------------------------------------ 8242( 5) - 02/28/00 11:41 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 UGC4277 GALAXY RA=8H 13M 57.3S +/- 2", DEC=52D J2000 V = 5500 B = 14.9+/-0.1 38' 52.2" +/- 2" A(B) = 0.11+/-0.03 2 NGC4217 GALAXY RA=12H 15M 48.4S +/- 2", DEC=47D J2000 V = 1028 B = 12.0+/-0.1 4' 51.2" +/- 2" A(B) = 0.0+/-0.03 3 NGC4302 GALAXY RA=12H 21M 43.2S +/- 2", DEC=14D J2000 V = 1149 B = 12.5+/-0.1 36' 2.5" +/- 2" A(B) = 0.07+/-0.03 4 NGC4013 GALAXY RA=11H 58M 31.3S +/- 2", DEC=43D J2000 V = 834 B = 12.2+/-0.1 56' 50.5" +/- 2" A(B) = 0.00+/-0.03 8242( 5) - 02/28/00 11:41 - [ 5] Visit: 01 Visit Priority: Visit Requirements: ORIENT 0D TO 90D ORIENT 140D TO 270D ORIENT 320D TO 360D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 UGC4277 WFPC2 IMAGE WFALL-F F555W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S IX ------------------------------------------------------------------------------------------------------------------------------------ 20 UGC4277 WFPC2 IMAGE WFALL-F F450W DITHER-TYPE=LINE,CR-SPLIT=DEF 2 1000 S IX ------------------------------------------------------------------------------------------------------------------------------------ 30 UGC4277 WFPC2 IMAGE WFALL-F F814W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S IX ------------------------------------------------------------------------------------------------------------------------------------ 8242( 5) - 02/28/00 11:41 - [ 6] Visit: 02 Visit Priority: Visit Requirements: ORIENT 50D TO 270D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC4302 WFPC2 IMAGE WFALL-F F555W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S IX ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC4302 WFPC2 IMAGE WFALL-F F450W DITHER-TYPE=LINE,CR-SPLIT=DEF 2 1000 S IX ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC4302 WFPC2 IMAGE WFALL-F F814W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S IX ------------------------------------------------------------------------------------------------------------------------------------ 8242( 5) - 02/28/00 11:41 - [ 7] Visit: 03 Visit Priority: Visit Requirements: ORIENT 127D TO 180D ORIENT 195D TO 220D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC4217 WFPC2 IMAGE WFALL-F F555W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S IX ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC4217 WFPC2 IMAGE WFALL-F F814W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S IX ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC4217 WFPC2 IMAGE WFALL-F F450W DITHER-TYPE=LINE,CR-SPLIT=DEF 2 1000 S IX ------------------------------------------------------------------------------------------------------------------------------------ 8242( 5) - 02/28/00 11:41 - [ 8] Visit: 04 Visit Priority: Visit Requirements: ORIENT 0D TO 170D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC4013 WFPC2 IMAGE PC1-FIX F450W CR-SPLIT=DEF,ATD-GAIN=15 2 1000 S ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC4013 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=DEF,ATD-GAIN=15 1 1000 S ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC4013 WFPC2 IMAGE PC1-FIX F814W CR-SPLIT=DEF,ATD-GAIN=15 1 1000 S ------------------------------------------------------------------------------------------------------------------------------------ 8242( 5) - 02/28/00 11:41 - [ 9] Visit: 05 Visit Priority: Visit Requirements: ORIENT 185D TO 315D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC4013 WFPC2 IMAGE PC1-FIX F555W DITHER-TYPE=LINE,CR-SPLIT=DEF, 1 1000 S ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC4013 WFPC2 IMAGE PC1-FIX F450W DITHER-TYPE=LINE,CR-SPLIT=DEF, 2 1000 S ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC4013 WFPC2 IMAGE PC1-FIX F814W DITHER-TYPE=LINE,CR-SPLIT=DEF, 1 1000 S ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 8242( 5) - 02/28/00 11:41 - [ 10] Visit: 11 Visit Priority: Visit Requirements: ORIENT 0D TO 90D ORIENT 140D TO 270D ORIENT 320D TO 360D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 UGC4277 WFPC2 IMAGE WFALL-F F555W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S IX ------------------------------------------------------------------------------------------------------------------------------------ 20 UGC4277 WFPC2 IMAGE WFALL-F F450W DITHER-TYPE=LINE,CR-SPLIT=DEF 2 1000 S IX ------------------------------------------------------------------------------------------------------------------------------------ 30 UGC4277 WFPC2 IMAGE WFALL-F F814W DITHER-TYPE=LINE,CR-SPLIT=DEF 1 1000 S IX ------------------------------------------------------------------------------------------------------------------------------------ 8242( 5) - 02/28/00 11:41 - [ 11] Summary Form for Proposal 8242 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFALL-FIX PC1-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters DITHER-TYPE=LINE CR-SPLIT=DEF ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 0D TO 90D ORIENT 140D TO 270D ORIENT 320D TO 360D ORIENT 50D TO 270D ORIENT 127D TO 180D ORIENT 195D TO 220D ORIENT 0D TO 170D ORIENT 185D TO 315D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W F450W F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names UGC4277 NGC4302 NGC4217 NGC4013 ------------------------------------------------------------------------------------------------------------------------------------