0 Assigned ID: 703 ----- Attempting Submission 1 (Fri Apr 11 19:19:18 GMT 2014) ----- HST Phase I Proposal 703 (n253_pb_v2.apt) successfully submitted. ----- Attempting Submission 2 (Fri Apr 11 21:02:21 GMT 2014) ----- HST Phase I Proposal 703 (n253_pb_v2.apt) successfully submitted. ----- Attempting Submission 3 (Fri Apr 11 21:13:34 GMT 2014) ----- This is my first time preparing a phase II proposal, so any feedback or suggestions most appreciated. I have chosen the drizzle pattern and readout properties to match archival observations of the same object (also narrow filter WFC3) while matching the exposure that we estimated was necessary via the ETC. Again, suggestions welcome. 473822122 ----- Attempting Submission 1 (Thu Jul 24 16:09:07 GMT 2014) ----- We propose narrow band WFC3 infrared imaging of the central part of NGC 253, the nearest nuclear starburst, with the goal of imaging the location of recent star formation traced by the Paschen $\beta$ line. We will compare the distribution of Pa$\beta$ emission to our understanding of the molecular ISM, built on a series of successful ALMA programs. These have revealed the location of star-forming clouds, shells carved by feedback, molecular outflows emerging from the disk, and a rich suite of interstellar molecules. Knowing exactly where (and how many) stars are forming is key to make the best use of these data. From the comparison of ALMA and HST Pa$\beta$ data, we will be able to assess the efficiencies of feedback, test models of star formation, and help establish the interpretation of new molecular tracers. Our proposed observations target the off-line filter (F130N) and will be combined with archival on-line imaging (F128N). Right now, those on-line data are not useful for science because the broad band data are inadequate for a quality continuum subtraction. This program aims to combine with the archive to produce relatively deep matched narrow band on and off line observations of Paschen Beta in the central part of the nearby starburst galaxy NGC 253. This will yield maps of ionizing photon production that are comparatively robust to extinction, which we aim to compare with existing and awarded ALMA observations of the dense, star-forming molecular gas (also at comparatively high resolution) in the same region. Variable, heavy extinction hampered the attempt in the archive to use broad band measurements for continuum subtraction so we pursue this simpler and more robust, though somewhat more costly approach. ISM IN EXTERNAL GALAXIES Default false false false false false SUPPORTED GALAXY STARBURST This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 WFC3/IR Imaging No No F130N WFC3/IR Imaging No No F128N POS-TARG DITHER 0.605 LINE false false 3 41.788 WFC3-IR-DITHER-LINE-3PT 1 false 1406217611870 The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. 1413595552000 15.026261750596603 (Tic-Visit :proposal-id 13730 :visit-id "01" :proposal-version -1 :trans-version "20140605" :date "24-Jul-2014 12:00:11.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1148976 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13730 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13730 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2896 :al-overhead-at-end 0 :internal-dur-at-end 557 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3241 :pcs-gap 0 ) true 1 0