0 Assigned ID: 3277 ----- Attempting Submission 1 (Fri Mar 25 15:35:44 GMT 2022) ----- HST Phase I Proposal 3277 successfully submitted. Receipt: # 3277-1 ----- Attempting Submission 2 (Fri Mar 25 22:06:53 GMT 2022) ----- HST Phase I Proposal 3277 successfully submitted. Receipt: # 3277-2 ----- Attempting Submission 3 (Fri Mar 25 23:38:19 GMT 2022) ----- 0 ----- Attempting Submission 1 (Thu Jul 14 18:17:49 GMT 2022) ----- Studying ionizing photon escape from a bright gravitationally lensed reionization era analog at z=1.43 We propose WFC3 UVIS/G280 grism observations of a bright lensed galaxy at z=1.43 to measure ionizing (LyC) photons escaping from the system. The combination of unique brightness (g=20.7) and lensing magnification allows measurement of ionizing photon escape at sub-kpc level. The existing ground-based spectroscopy shows spectral features similar to a reionization-era galaxies. Furthermore, the galaxy shows tell-tale signs of ionizing photon production and escape. Based on the newly developed indirect measure of LyC photons using Mg II emission lines, we estimate ionizing photons escape fraction (dust corrected) of 36+/-11%. Our proposed observations will help understand (i) the connection between Mg II emission and LyC photons, (ii) the effects of stellar feedback on LyC photon escape, and (iii) allow spatially resolved Lyman-alpha map in a reionization era analog. This source is one of three at any redshift where a spatially resolved study of LyC photons is possible. This study will add to the extremely rare class of bright lensed systems showing LyC leakage, which will provide further insight to the LyC escape. 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=20.7) at z=1.43. 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 36 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 James is an expert in the spectroscopy of bright lensed galaxies (James et a. 2014, 2018). Co-I Berg is an expert in reduction and analysis of HST UVIS grism data. Galaxies Intergalactic Medium and the Circumgalactic Medium 6 false false false false false false false false SUPPORTED GALAXY GRAVITATIONAL LENS HIGH REDSHIFT GALAXY J2000 J2000 WFC3/UVIS Spectroscopic No No G280 The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. 1685352980000 156.0 (Tic-Visit :proposal-id 17138 :visit-id "01" :proposal-version -1 :trans-version "20220516" :date "14-Jul-2022 14:15:52.0" :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 17138 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17138 :visit-id "01" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2766 :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 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17138 :visit-id "01" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2757 :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 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17138 :visit-id "01" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2757 :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 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17138 :visit-id "01" :orbit-number 4 :pcs-time 392 :si-vis-utilization 2757 :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 3149 :pcs-gap 0 ) true 4 0 The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. (Tic-Visit :proposal-id 17138 :visit-id "02" :proposal-version -1 :trans-version "20220516" :date "14-Jul-2022 14:17:20.0" :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 17138 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17138 :visit-id "02" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2764 :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 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17138 :visit-id "02" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2757 :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 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17138 :visit-id "02" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2757 :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 3149 :pcs-gap 0 ) false 3 0 The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. (Tic-Visit :proposal-id 17138 :visit-id "03" :proposal-version -1 :trans-version "20220516" :date "14-Jul-2022 14:17:20.0" :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 17138 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17138 :visit-id "03" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2764 :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 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17138 :visit-id "03" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2757 :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 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17138 :visit-id "03" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2757 :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 3149 :pcs-gap 0 ) false 3 0