14186( 3) - 23-Jul-2015 17:36:05 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14186 Version: 3 Check-in Time: 23-Jul-2015 17:36:05 STScI Edit Number: 0 Title Mapping dust extinction properties across the IC 63 photodissociation region ------------------------------------------------------------------------------------ Type Cycle GO 23 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Heddy Arab Space Telescope Science Institute Y CoI: Dr. Karl D. Gordon Space Telescope Science Institute N CoI: Dr. Julia Christine Roman-Duval Space Telescope Science Institute - ESA N CoI: Dr. Brandon Lawton Space Telescope Science Institute N CoI: Kirill Tchernyshyov The Johns Hopkins University N ------------------------------------------------------------------------------------ Abstract Dust plays a crucial role in the chemical and dynamical evolution of the ISM. Its physical and chemical properties are however not well constrained. Photo-dissociation regions (PDRs), located at the interface between H II regions and molecular clouds, are ideal objects to study the properties and evolution of dust grains, because physical conditions within them change on very short length scales. In order to determine how the dust extinction parameters vary across a PDR, we propose to map the IC 63 PDR from the UV to the near infrared at high resolution with HST WFC3, similarly to the approach taken in the Panchromatic Hubble Andromeda Treasury (PHAT). These observations will allow us to derive simultaneously stellar (spectral type, effective temperature and luminosity) and extinction parameters (Av, Rv) for many background stars behind IC 63. The spectral type will identify prime candidates for followup HST UV/spectroscopy, whereas extinction parameter maps will reveal for the first time the extinction variations across a PDR. We will gain valuable information on how the grain size distribution and optical properties of dust are affected by the strong density gradient and the sharp changes in the physical conditions, such as radiation field, typical of PDRs. The results of this study will bring new constraints on the modeling of dust formation and processing in the ISM. Moreover, this analysis combined with ancillary data from Spitzer and Herschel will give for the first time a complete view of dust within a PDR. ------------------------------------------------------------------------------------ Observations Description ------------------------ Our observations cover a WFC3 field centered on the IC 63 reflection nebula. The coverage of the observations is 162x162 arcsec and 123x136 arcsec for the UVIS and IR channel respectively. The set of 7 filters used in this program (F275W, F336W, F475W, F625W, F814W for the UVIS channel and F110W and F160W for the IR channel) has been defined to optimally extract dust extinction parameters by fitting stellar spectral energy distributions. To maximize the observed area of the PDR, an orientation angle of 216 degrees is required. This extinction mapping technique needs numerous and spatially well-sampled sightlines on IC 63, putting a strong constraint on the depth of the observations: the final extinction map pixel (~10 arcsec) has to contain at least a dozen of individual sources. 14186( 3) - 23-Jul-2015 17:36:05 - [ 2] The program consists in two visits, each of two orbits. The first orbit includes most of our UV exposures (2x600s in F275W and 2x650s in F336W). That first orbit ends with a 5s guard exposure in F475W to retrieve information about the brightest sources. The second orbit contains 4x449s exposures in F814W and our observations in F160W. We use MULTIACCUM STEP50 sequences with NSAMP = 13 (for a total of 2x400s) to observe the infrared sources on a wide magnitude range. The second visit starts with 4x420s exposures in F625W and 2x350s in F110W (STEP50 NSAMP=12). Those infrared exposures are separated from the F160W observations to avoid persistence. That is also why we impose the second visit to happen at least 2 days after the first visit. A 5s guard exposure is also taken in F814W. The last orbit includes 4x450s exposures in F475W and two additional 349s exposures in F275W. To step over macroscopic features of the detector (such as the UVIS chip gap) and to aid in cosmic ray removal, we adopt a gap line dither pattern for most of the UVIS exposures (no dithering is used for the guard exposures). However to keep the effects of IR persistence localized, we use a small line pattern in the IR. ------------------------------------------------------------------------------------ 14186( 3) - 23-Jul-2015 17:36:05 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 IC-63 ISM, HII REGION, PDR, RA=00H59M4.8572S, J2000 V = 15.26 REFLECTION NEBULA DEC=+60D53'55.42" Reference Frame: Other: SIMBAD Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 14186( 3) - 23-Jul-2015 17:36:05 - [ 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 NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.636 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 41.788 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 14186( 3) - 23-Jul-2015 17:36:05 - [ 5] Visit: 01 Visit Requirements: ORIENT 216D TO 216 D 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 IC-63 WFC3/UVI ACCUM UVIS-FIX F275W CR-SPLIT=NO, FLASH=10 1 600 S POS TARG S (1200 S) 0.23497375345510974, -35.823189160689175; PATTERN 1 1-2 ------------------------------------------------------------------------------------------------------------------------------------ 2 IC-63 WFC3/UVI ACCUM UVIS-FIX F336W CR-SPLIT=NO, FLASH=10 1 650 S POS TARG S (1300 S) 0.23497375345510974, -35.823189160689175 ------------------------------------------------------------------------------------------------------------------------------------ 3 IC-63 WFC3/UVI ACCUM UVIS-FIX F475W CR-SPLIT=NO, FLASH=11 1 5 S (5 S) POS TARG S 0.23497375345510974, -35.823189160689175 ------------------------------------------------------------------------------------------------------------------------------------ 4 IC-63 WFC3/UVI ACCUM UVIS-FIX F814W CR-SPLIT=NO, FLASH=2 2 449 S POS TARG S (1796 S) 0.23497375345510974, -35.823189160689175; PATTERN 1 4 ------------------------------------------------------------------------------------------------------------------------------------ 5 IC-63 WFC3/IR MULTIAC IR-UVIS F160W NSAMP=13, SAMP-SEQ=STEP50 1 DEF POS TARG CUM (798.467 12.99485326496644, S) -6.268690824596547; PATTERN 2 5 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ IC-63 1 WFC3/UVI ACCUM UVIS-FIX F275W 1 none none none 1 N/A S IC-63 1 WFC3/UVI ACCUM UVIS-FIX F275W 2 none none none 1 N/A S IC-63 2 WFC3/UVI ACCUM UVIS-FIX F336W 1 none none none 1 N/A S IC-63 2 WFC3/UVI ACCUM UVIS-FIX F336W 2 none none none 1 N/A S IC-63 3 WFC3/UVI ACCUM UVIS-FIX F475W none none none none 1 N/A S IC-63 4 WFC3/UVI ACCUM UVIS-FIX F814W 1 none 1 none 2 N/A S 14186( 3) - 23-Jul-2015 17:36:05 - [ 6] 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 | ------------------------------------------------------------------------------------------------------------------------------------ IC-63 4 WFC3/UVI ACCUM UVIS-FIX F814W 1 none 2 none 2 N/A S IC-63 4 WFC3/UVI ACCUM UVIS-FIX F814W 2 none 1 none 2 N/A S IC-63 4 WFC3/UVI ACCUM UVIS-FIX F814W 2 none 2 none 2 N/A S IC-63 5 WFC3/IR MULTIAC IR-UVIS F160W 1 none none none 2 N/A CUM IC-63 5 WFC3/IR MULTIAC IR-UVIS F160W 2 none none none 2 N/A CUM 14186( 3) - 23-Jul-2015 17:36:05 - [ 7] Visit: 02 Visit Requirements: ORIENT 216D TO 216 D; AFTER 01 BY 2 D TO 50 D 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 IC-63 WFC3/UVI ACCUM UVIS-FIX F625W CR-SPLIT=NO 2 420 S POS TARG S (1680 S) 0.23497375345510974, -35.823189160689175; PATTERN 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 IC-63 WFC3/IR MULTIAC IR-UVIS F110W NSAMP=12, SAMP-SEQ=STEP50 1 DEF POS TARG CUM (698.466 12.99485326496644, S) -6.268690824596547; PATTERN 2 2 ------------------------------------------------------------------------------------------------------------------------------------ 3 IC-63 WFC3/UVI ACCUM UVIS F814W CR-SPLIT=NO, FLASH=11 1 5 S (5 S) POS TARG S 0.23497375345510974, -35.823189160689175 ------------------------------------------------------------------------------------------------------------------------------------ 4 IC-63 WFC3/UVI ACCUM UVIS-FIX F475W CR-SPLIT=NO, FLASH=3 2 450 S POS TARG S (1800 S) 0.23497375345510974, -35.823189160689175; PATTERN 1 4-5 ------------------------------------------------------------------------------------------------------------------------------------ 5 IC-63 WFC3/UVI ACCUM UVIS-FIX F275W CR-SPLIT=NO, FLASH=11 1 349 S (698 POS TARG S S) 0.23497375345510974, -35.823189160689175 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ IC-63 1 WFC3/UVI ACCUM UVIS-FIX F625W 1 none 1 none 1 N/A S IC-63 1 WFC3/UVI ACCUM UVIS-FIX F625W 1 none 2 none 1 N/A S IC-63 1 WFC3/UVI ACCUM UVIS-FIX F625W 2 none 1 none 1 N/A S IC-63 1 WFC3/UVI ACCUM UVIS-FIX F625W 2 none 2 none 1 N/A S IC-63 2 WFC3/IR MULTIAC IR-UVIS F110W 1 none none none 1 N/A CUM IC-63 2 WFC3/IR MULTIAC IR-UVIS F110W 2 none none none 1 N/A CUM 14186( 3) - 23-Jul-2015 17:36:05 - [ 8] 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 | ------------------------------------------------------------------------------------------------------------------------------------ IC-63 3 WFC3/UVI ACCUM UVIS F814W none none none none 1 N/A S IC-63 4 WFC3/UVI ACCUM UVIS-FIX F475W 1 none 1 none 2 N/A S IC-63 4 WFC3/UVI ACCUM UVIS-FIX F475W 1 none 2 none 2 N/A S IC-63 4 WFC3/UVI ACCUM UVIS-FIX F475W 2 none 1 none 2 N/A S IC-63 4 WFC3/UVI ACCUM UVIS-FIX F475W 2 none 2 none 2 N/A S IC-63 5 WFC3/UVI ACCUM UVIS-FIX F275W 1 none none none 2 N/A S IC-63 5 WFC3/UVI ACCUM UVIS-FIX F275W 2 none none none 2 N/A S 14186( 3) - 23-Jul-2015 17:36:05 - [ 9] Summary Form for Proposal 14186 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR-UVIS, UVIS, UVIS-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO, FLASH=10, FLASH=11, FLASH=2, FLASH=3, NSAMP=12, NSAMP=13, SAMP-SEQ=STEP50 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01 BY 2 D TO 50 D, ORIENT 216D TO 216 D, PATTERN 1 1, PATTERN 1 1-2, PATTERN 1 4, PATTERN 1 4-5, PATTERN 2 2, PATTERN 2 5, POS TARG 0.23497375345510974, -35.823189160689175, POS TARG 12.99485326496644, -6.268690824596547 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F110W, F160W, F275W, F336W, F475W, F625W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names IC-63 ------------------------------------------------------------------------------------------------------------------------------------