0 Assigned ID: 691 ----- Attempting Submission 1 (Fri Apr 10 19:08:59 GMT 2015) ----- HST Phase I Proposal 691 (IC_63_cycle23_v3.apt) successfully submitted. Receipt: # 691-1 ----- Attempting Submission 2 (Fri Apr 10 22:31:00 GMT 2015) ----- HST Phase I Proposal 691 (IC_63_cycle23_v3.apt) successfully submitted. Receipt: # 691-2 ----- Attempting Submission 3 (Fri Apr 10 23:16:55 GMT 2015) ----- HST Phase I Proposal 691 (IC_63_cycle23_v3.apt) successfully submitted. Receipt: # 691-3 ----- Attempting Submission 4 (Fri Apr 10 23:53:20 GMT 2015) ----- HST Phase I Proposal 691 (IC_63_cycle23_v3.apt) successfully submitted. Receipt: # 691-4 ----- Attempting Submission 5 (Sat Apr 11 00:04:42 GMT 2015) ----- HST Phase I Proposal 691 (IC_63_cycle23_v3.apt) successfully submitted. Receipt: # 691-5 ----- Attempting Submission 6 (Sat Apr 11 00:11:11 GMT 2015) ----- 0 ----- Attempting Submission 1 (Wed Jul 22 17:22:08 GMT 2015) ----- HST Phase II Proposal 14186 (IC63_proposal_21july15bis.apt) successfully submitted. Receipt: # 14186-1 ----- Attempting Submission 2 (Thu Jul 23 17:31:12 GMT 2015) ----- Mapping dust extinction properties across the IC 63 photodissociation region 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. 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. 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. ISM AND CIRCUMSTELLAR MATTER 12 false false false false SUPPORTED ISM HII REGION PDR REFLECTION NEBULA This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 WFC3/UVIS Imaging No No F275W WFC3/UVIS Imaging No No F336W WFC3/UVIS Imaging No No F475W WFC3/UVIS Imaging No No F814W WFC3/IR Imaging No No F110W WFC3/IR Imaging No No F160W POS-TARG MOSAIC DITHER 4 2.414 WFC3-UVIS-DITHER-BOX false 81.785 false 0.112 0.173 2 85.759 POS-TARG WFC3-UVIS-GAP-LINE 23.884 1 false POS-TARG DITHER 0.636 LINE false false 2 41.788 WFC3-IR-DITHER-LINE 2 false /private/var/folders/qt/k8t4lmz52m59xhyh3vxl4m5400052h/T/OPVisit6185810591021221682.xml Timing link suitability includes constraints ([02 After 01 by 2.0 to 50.0 days]) The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. 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