17717( 4) - 14-Jan-2025 15:28:05 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17717 Version: 4 Check-in Time: 14-Jan-2025 15:28:05 STScI Edit Number: 0 Title Resolving the Origins of Extraplanar Dust using UV Reflection Nebulae ------------------------------------------------------------------------------------ Type Cycle GO 32 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Erin Boettcher University of Maryland Y CoI: Dr. Edmund Hodges-Kluck NASA Goddard Space Flight Center N ------------------------------------------------------------------------------------ Abstract Dusty outflows from star-forming regions trace the circulation of mass and metals between galaxy disks and their gaseous environments. As much as half of the dust in the local universe may be found outside of galaxy disks, but we do not know what physical mechanisms dominate the dust transport. The morphology of the extraplanar dust is a key indicator of dust transport by ejective feedback through galactic chimneys (clumpy/filamentary) or by radiation pressure (smooth). However, the dust morphology is unknown at distances of more than a kiloparsec from the disks of normal, star-forming galaxies. At these distances, UV light scattered by dust grains provides a powerful tool for detecting the dust, but these reflection nebulae are unresolved by GALEX and Swift observations. We propose to resolve these nebulae using HST/WFC3 F225W imaging of six nearby, normal ~L* galaxies (five new observations, one archival). These observations will determine whether ejective feedback or radiation pressure dominates the dust transport out of galaxy disks with and without active chimney-mode feedback, as seen in H-alpha images. This pilot program will also enable efficient and precise measurements of the metal mass found in the expelled dust in a future program. These objectives are essential for understanding the physical processes that regulate star formation by coupling the mass and metal reservoirs of the interstellar and circumgalactic media. ------------------------------------------------------------------------------------ Observations Description ------------------------ Scientific goals: This program will study ejective and radiative stellar feedback in star-forming disk galaxies by measuring the morphology of extraplanar dust detected via scattered UV light. If ejective feedback dominates the dust transport out of galaxy disks, then the extraplanar dust morphology is expected to be clumpy. In contrast, if radiative feedback is important, then the morphology will be smoother. Our observing strategy is therefore designed to detect scattered light from dust on scales as small as l = 100 pc at the disk-halo interfaces of five nearby (D = 10 - 20 Mpc), edge-on disk galaxies. These obseravtions will also inform the best strategy for obtaining accurate measurements of the total extraplanar dust mass in future observing programs. Observing strategy: We use WFC3-UVIS and the F225W filter to image extraplanar dust via scattered near-UV light in high SNR images. Our exposure times are chosen to detect extraplanar dust in regions of size l = 100 pc (1" - 2", or 25 - 50 pixels) at z = 3 kpc with SNR = 3, if the dust is smooth. The choice of z 17717( 4) - 14-Jan-2025 15:28:05 - [ 2] = 3 kpc is based on the typical extent of extraplanar reflection nebulae, and we use GALEX/NUV images to determine the typical NUV surface brightnesses of the sample galaxies at these distances from the disk. If the dust is clumpy instead of smooth, we will achieve a higher SNR in the clumps, and we will enlarge the aperture as needed to achieve significant detections of any residual, diffuse emission. The exposure time requirements result in two orbits allocated to each of the five galaxies for a total of ten orbits. We center the WFC3-UVIS pointings on the galaxy centers, where the NUV halos tend to be brightest, to optimize the SNR. The WFC3-UVIS FOV spans 8 - 18 kpc at the distances of the sample galaxies, allowing the extraplanar NUV surface brightness profile to be measured within at least twice the characteristic scale height of the NUV nebulae (typically a few kiloparsecs). We use the two-point WFC3-UVIS-GAP-LINE pattern to fill in the chip gap and remove cosmic rays and detector artifacts. As the scales that we aim to resolve (~ 1") are larger than the PSF, we do not dither further to resample the PSF. We employ a post-flash of 9 or 10 e- to mitigate CTE effects in the faint regions of the images. We thus obtain two full-orbit exposures for each galaxy, which optimizes the SNR of faint extraplanar structures. ------------------------------------------------------------------------------------ 17717( 4) - 14-Jan-2025 15:28:05 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4517 GALAXY, SPIRAL RA=12H32M45.5904S, J2000 Z = V = 10.4 SURF-NUV-AB = 25.3 mag/sqarc DEC=+00D06'54.11" 0.003756 Reference Frame: Other: NED Comments: This object was generated by the targetselector and retrieved from the NED database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.0 0.0 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4565 GALAXY, SPIRAL RA=12H36M20.8040S, J2000 Z = V = 9.6 SURF-NUV-AB = 25.5 mag/sqarc DEC=+25D59'14.61" 0.004276 Reference Frame: Other: SIMBAD Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2015.5 0.0 0.0 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC3044 GALAXY, SPIRAL RA=09H53M40.8840S, J2000 Z = V = 11.9 mu_NUV_AB = 24.5 mag/sqarc DEC=+01D34'46.74" 0.0043 Reference Frame: Other: SIMBAD Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2015.5 0.0 0.0 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC4217 GALAXY, SPIRAL RA=12H15M50.9000S, J2000 Z = V = 11.2 mu_NUV_AB = 25.6 mag/sqarc DEC=+47D05'30.44" 0.003429 Reference Frame: Other: SIMBAD Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2015.5 0.0 0.0 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC2683 GALAXY, SPIRAL RA=08H52M41.3065S, J2000 Z = V = 9.79 mu_NUV_AB = 25.3 mag/sqarc DEC=+33D25'18.60" 0.001371 Reference Frame: Other: SIMBAD Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.0 0.0 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 17717( 4) - 14-Jan-2025 15:28:05 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-GAP-LINE Pattern_Purpose MOSAIC Number_Of_Points 2 Point_Spacing 2.414 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 85.759 Angle_Between_Sides Center_Pattern YES ------------------------------------------------------------------------------------------------------------------------------------ 17717( 4) - 14-Jan-2025 15:28:05 - [ 5] Visit: 01 (NGC4517 Visit) Visit Requirements: ORIENT 10D TO 275 D On Hold Comments: Additional Comments: A bright star within the FOV (RA = 188.20335d, dec = 0.12584d; V ~ 10.9 mag) may produce figure-8 ghosts in quadrant A if it falls on quadrant D. We restrict the ORIENT to ensure that the star does not fall on quadrant D. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4517 WFC3/UVI ACCUM UVIS-FIX F225W FLASH=10 1 2500 S PATTERN 1 1 S see below (5211 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NGC4517 1 WFC3/UVI ACCUM UVIS-FIX F225W 1 none none none 1 2617.0 S S NGC4517 1 WFC3/UVI ACCUM UVIS-FIX F225W 2 none none none 2 2594.0 S S 17717( 4) - 14-Jan-2025 15:28:05 - [ 6] Visit: 02 (NGC4565 Visit) Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4565 WFC3/UVI ACCUM UVIS-FIX F225W FLASH=9 1 2620 S PATTERN 1 1 S see below (5265 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NGC4565 1 WFC3/UVI ACCUM UVIS-FIX F225W 1 none none none 1 2644.0 S S NGC4565 1 WFC3/UVI ACCUM UVIS-FIX F225W 2 none none none 2 2621.0 S S 17717( 4) - 14-Jan-2025 15:28:05 - [ 7] Visit: 03 (NGC3044 Visit) Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC3044 WFC3/UVI ACCUM UVIS-FIX F225W FLASH=10 1 2590 S PATTERN 1 1 S see below (5211 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NGC3044 1 WFC3/UVI ACCUM UVIS-FIX F225W 1 none none none 1 2617.0 S S NGC3044 1 WFC3/UVI ACCUM UVIS-FIX F225W 2 none none none 2 2594.0 S S 17717( 4) - 14-Jan-2025 15:28:05 - [ 8] Visit: 04 (NGC4217 Visit) Visit Requirements: ORIENT 30D TO 275 D; ORIENT 310D TO 350 D On Hold Comments: Additional Comments: A very bright star just outside of the FOV (RA = 183.97958d, dec = 47.12711d; V ~ 9 mag) may cause a dragon's breath artifact for certain ORIENTs. Based on the examples of this artifact provided in the WFC3-UVIS handbook for 9th magnitude stars, we exclude ORIENTs where the bright star falls < 30" from the edge of the FOV. Please include two ranges of ORIENTs as permissible: MinORIENT = 30 degrees, MaxORIENT = 275 degrees and MinORIENT = 310 degrees, MaxORIENT = 350 degrees. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4217 WFC3/UVI ACCUM UVIS-FIX F225W FLASH=9 1 2650 S PATTERN 1 1 S see below (5325 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NGC4217 1 WFC3/UVI ACCUM UVIS-FIX F225W 1 none none none 1 2674.0 S S NGC4217 1 WFC3/UVI ACCUM UVIS-FIX F225W 2 none none none 2 2651.0 S S 17717( 4) - 14-Jan-2025 15:28:05 - [ 9] Visit: 05 (NGC2683 Visit) Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC2683 WFC3/UVI ACCUM UVIS-FIX F225W FLASH=9 1 2600 S PATTERN 1 1 S see below (5269 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NGC2683 1 WFC3/UVI ACCUM UVIS-FIX F225W 1 none none none 1 2646.0 S S NGC2683 1 WFC3/UVI ACCUM UVIS-FIX F225W 2 none none none 2 2623.0 S S 17717( 4) - 14-Jan-2025 15:28:05 - [ 10] Visit: 06 (Repeat of NGC4565, Orbit 2) Visit Requirements: On Hold Comments: Additional Comments: This is a repeat of the second orbit of Visit 02, which had degraded data quality due to a guide star reacquisition failure. We do not attempt to reproduce the orient angle from Visit 02 in order to maximize the schedulability. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4565 WFC3/UVI ACCUM UVIS-FIX F225W FLASH=9.0 1 2620 S S see below (2644 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NGC4565 1 WFC3/UVI ACCUM UVIS-FIX F225W none none none none 1 2644.0 S S 17717( 4) - 14-Jan-2025 15:28:05 - [ 11] Summary Form for Proposal 17717 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=10, FLASH=9, FLASH=9.0 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 10D TO 275 D, ORIENT 30D TO 275 D, ORIENT 310D TO 350 D, PATTERN 1 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F225W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC2683, NGC3044, NGC4217, NGC4517, NGC4565 ------------------------------------------------------------------------------------------------------------------------------------