17138( 3) - 14-Jun-2023 17:20:14 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17138 Version: 3 Check-in Time: 14-Jun-2023 17:20:14 STScI Edit Number: 1 Title Studying ionizing photon escape from a bright gravitationally lensed reionization era analog at z=1.43 ------------------------------------------------------------------------------------ Type Cycle GO 30 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Ramesh Mainali NASA Goddard Space Flight Center Y CoI: Dr. Jane R. Rigby NASA Goddard Space Flight Center N CoI: Prof. Daniel P. Stark University of Arizona N CoI: Prof. John Chisholm University of Texas at Austin N CoI: Dr. Bethan Lesley James Space Telescope Science Institute - ESA - N JWST CoI: Dr. Michelle Berg University of Texas at Austin N ------------------------------------------------------------------------------------ Abstract 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. ------------------------------------------------------------------------------------ Observations Description ------------------------ 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 17138( 3) - 14-Jun-2023 17:20:14 - [ 2] nearby bright sources around the wavelength of interests. ------------------------------------------------------------------------------------ 17138( 3) - 14-Jun-2023 17:20:14 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 CSWA-20 GALAXY, GRAVITATIONAL RA=14H41M49.1500S +/- 0.5", J2000 Z = 1.43 V = 20.7 +/- 0.1 LENS, HIGH REDSHIFT DEC=+14D41'20.60" +/- 0.5" GALAXY Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 17138( 3) - 14-Jun-2023 17:20:14 - [ 4] Visit: 01 Visit Requirements: ORIENT 150D TO 156 D; ORIENT 330D TO 336 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 CSWA-20 WFC3/UVI ACCUM G280-REF F300X CR-SPLIT=2, FLASH=19 1 400 S (400 POS TARG null, -50 S S) ------------------------------------------------------------------------------------------------------------------------------------ 2 CSWA-20 WFC3/UVI ACCUM UVIS G280 1 2074 S POS TARG null, -50 S (2074 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 CSWA-20 WFC3/UVI ACCUM UVIS G280 1 2740 S POS TARG null, -50 S see below (2749 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 CSWA-20 WFC3/UVI ACCUM UVIS G280 1 2700 S POS TARG null, -50 S see below (2749 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 CSWA-20 WFC3/UVI ACCUM UVIS G280 1 2700 S POS TARG null, -50 S see below (2749 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ CSWA-20 1 WFC3/UVI ACCUM G280-REF F300X none none none 1 1 N/A S CSWA-20 1 WFC3/UVI ACCUM G280-REF F300X none none none 2 1 N/A S CSWA-20 2 WFC3/UVI ACCUM UVIS G280 none none none none 1 N/A S CSWA-20 3 WFC3/UVI ACCUM UVIS G280 none none none none 2 2749.0 S S CSWA-20 4 WFC3/UVI ACCUM UVIS G280 none none none none 3 2749.0 S S CSWA-20 5 WFC3/UVI ACCUM UVIS G280 none none none none 4 2749.0 S S 17138( 3) - 14-Jun-2023 17:20:14 - [ 5] Visit: 02 Visit Requirements: ORIENT 145D TO 145 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 CSWA-20 WFC3/UVI ACCUM G280-REF F300X CR-SPLIT=2, FLASH=19 1 400 S POS TARG -0.092, -50.098 S see below (448 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 CSWA-20 WFC3/UVI ACCUM UVIS G280 1 2000 S POS TARG -0.092, -50.098 S see below (2024 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 CSWA-20 WFC3/UVI ACCUM UVIS G280 1 2700 S POS TARG -0.092, -50.098 S see below (2749 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 CSWA-20 WFC3/UVI ACCUM UVIS G280 1 2700 S POS TARG -0.092, -50.098 S see below (2749 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ CSWA-20 1 WFC3/UVI ACCUM G280-REF F300X none none none 1 1 224.0 S S CSWA-20 1 WFC3/UVI ACCUM G280-REF F300X none none none 2 1 224.0 S S CSWA-20 2 WFC3/UVI ACCUM UVIS G280 none none none none 1 2024.0 S S CSWA-20 3 WFC3/UVI ACCUM UVIS G280 none none none none 2 2749.0 S S CSWA-20 4 WFC3/UVI ACCUM UVIS G280 none none none none 3 2749.0 S S 17138( 3) - 14-Jun-2023 17:20:14 - [ 6] Visit: 03 Visit Requirements: ORIENT 145D TO 145 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 CSWA-20 WFC3/UVI ACCUM G280-REF F300X CR-SPLIT=2, FLASH=19 1 400 S POS TARG -0.185, -50.197 S see below (448 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 CSWA-20 WFC3/UVI ACCUM UVIS G280 1 2000 S POS TARG -0.185, -50.197 S see below (2024 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 CSWA-20 WFC3/UVI ACCUM UVIS G280 1 2700 S POS TARG -0.185, -50.197 S see below (2749 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 CSWA-20 WFC3/UVI ACCUM UVIS G280 1 2700 S POS TARG -0.185, -50.197 S see below (2749 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ CSWA-20 1 WFC3/UVI ACCUM G280-REF F300X none none none 1 1 224.0 S S CSWA-20 1 WFC3/UVI ACCUM G280-REF F300X none none none 2 1 224.0 S S CSWA-20 2 WFC3/UVI ACCUM UVIS G280 none none none none 1 2024.0 S S CSWA-20 3 WFC3/UVI ACCUM UVIS G280 none none none none 2 2749.0 S S CSWA-20 4 WFC3/UVI ACCUM UVIS G280 none none none none 3 2749.0 S S 17138( 3) - 14-Jun-2023 17:20:14 - [ 7] Summary Form for Proposal 17138 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures G280-REF, UVIS ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=2, FLASH=19 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 145D TO 145 D, ORIENT 150D TO 156 D, ORIENT 330D TO 336 D, POS TARG -0.092, -50.098, POS TARG -0.185, -50.197, POS TARG null, -50 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F300X, G280 ------------------------------------------------------------------------------------------------------------------------------------ Target Names CSWA-20 ------------------------------------------------------------------------------------------------------------------------------------