0 Assigned ID: 2351 ----- Attempting Submission 1 (Fri Apr 09 22:18:57 GMT 2021) ----- HST Phase I Proposal 2351 successfully submitted. Receipt: # 2351-1 ----- Attempting Submission 2 (Fri Apr 09 23:52:59 GMT 2021) ----- FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser 0 ----- Attempting Submission 1 (Thu Jul 29 12:46:33 GMT 2021) ----- The background level has been increased to 20 e/pix as suggested by the Instrument Scientist. Measuring ionizing photon escape from an exceptionally bright gravitationally lensed arc at z=1.43 We propose WFC3 UVIS/G280 grism observations to measure escaping ionizing photons (LyC) from a galaxy at z=1.43 having nebular conditions similar to reionization era systems. The galaxy is a uniquely bright (r~20) gravitationally lensed system with an extended arc (9" long) allowing ionizing photon escape at a sub-kpc level. Based on a newly developed indirect measure of LyC escape fraction using Mg II emission lines, the galaxy is inferred to be a strong LyC leaker with ionizing photons escape fraction (dust corrected) of 27+/-4%. The proposed observations will (i) directly test the utility of Mg II based measure of LyC escape fraction for a high redshift galaxy, (ii) provide a sub-kpc map of ionizing photon escape allowing detailed probe of LyC escape. To date, only one source exists at any redshift where a spatially resolved study of LyC photons is possible. However, it is not clear whether the source is representative of reionization era galaxies. Our observations will exploit the ultraviolet capability of HST allowing the study of production and escape of ionizing photons from an exceptionally bright z=1.43 galaxy that is representative of reionization epoch. We will use WFC3 UVIS G280 grism to obtain Lyman continuum and Lyman-alpha in a bright gravitationally lensed arc (r=20.5) at z=1.425. We select the coordinates of the brightest star forming region as the RA/DEC and place it at the center of chip2 in order to boost the QE and flux calibration at shorter wavelengths. We split total 10 orbits into 3 visits (4 orbits, 3 orbits and 3 orbits) to improve schedulability. Prior to each visit, we will obtain two direct imaging using F300X with integration time of 200s each. For undispersed imaging, we will use G280-REF as an aperture. Following suggestion from the Instrument Scientist, we will use post-flash for the F300X images to achieve a background of ~20 electron/pix. In order to avoid contamination from a bright source, we request an ORIENT angle of 113 degree. This will ensure non contamination of spectra by nearby bright sources around the wavelength of interests. Our team comprises experts in the spectroscopy of reionization epoch galaxies and their analogs at lower redshifts. PI Mainali is an expert on spectroscopic studies of galaxies in the epoch of reionization (Mainali et al. 2018), and on the hardness of their ionizing populations (Mainali et al. 2017). PI Mainali has extensive experience in spectroscopic data analysis and photoionization modeling tools (Mainali et al. 2020). Co-I Rigby is a leader of a large spectroscopic survey of bright lensed galaxies (Megasaura; Rigby et al. 2018a,b). Co-I Stark is a leading expert in the field of high-redshift spectroscopy and reionization (Stark et al. 2010, Stark et al. 2015a,b, Stark et al. 2017). Co-I Chisholm is an expert on galaxy outflows and massive stellar populations in galaxies, and has pioneered several of the techniques to fit massive stellar populations which he also used to characterise the age and metallicity of the Lyman-continuum emitting region in the Sunburst Arc (Chisholm et al. 2019). Co-I Jones is an expert in spatially resolved study of lensed galaxies as well as analysis of HST/grism data (Jones et al. 2013, Jones et al. 2018) Galaxies Intergalactic Medium and the Circumgalactic Medium 6 false false false false false false false false SUPPORTED GALAXY GRAVITATIONAL LENS HIGH REDSHIFT GALAXY STARBURST J2000 J2000 WFC3/UVIS Spectroscopic No No G280 /private/var/folders/55/q93fxyjn3yj1vx9z3tktlbyh2dqhgd/T/OPVisit2166075911830534631.xml The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16710 :visit-id "01" :proposal-version -1 :trans-version "20210514" :date "28-Jul-2021 08:05:10.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1732464 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16710 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16710 :visit-id "01" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2759 :al-overhead-at-end 116 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3142 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16710 :visit-id "01" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2750 :al-overhead-at-end 116 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3142 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16710 :visit-id "01" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2750 :al-overhead-at-end 116 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3142 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16710 :visit-id "01" :orbit-number 4 :pcs-time 392 :si-vis-utilization 2750 :al-overhead-at-end 116 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3142 :pcs-gap 0 ) true 4 0 /private/var/folders/55/q93fxyjn3yj1vx9z3tktlbyh2dqhgd/T/OPVisit13146305612719239253.xml The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16710 :visit-id "02" :proposal-version -1 :trans-version "20210514" :date "28-Jul-2021 08:05:50.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1443728 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16710 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16710 :visit-id "02" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2759 :al-overhead-at-end 116 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3142 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16710 :visit-id "02" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2750 :al-overhead-at-end 116 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3142 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16710 :visit-id "02" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2750 :al-overhead-at-end 116 :internal-dur-at-end 352 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3142 :pcs-gap 0 ) true 3 0 /private/var/folders/55/q93fxyjn3yj1vx9z3tktlbyh2dqhgd/T/OPVisit3384181752522467894.xml The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16710 :visit-id "03" :proposal-version -1 :trans-version "20210514" :date "28-Jul-2021 08:06:12.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1443728 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16710 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16710 :visit-id "03" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2759 :al-overhead-at-end 116 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3142 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16710 :visit-id "03" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2750 :al-overhead-at-end 116 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3142 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16710 :visit-id "03" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2750 :al-overhead-at-end 116 :internal-dur-at-end 352 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3142 :pcs-gap 0 ) true 3 0