15418( 2) - 13-Dec-2017 14:15:21 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15418 Version: 2 Check-in Time: 13-Dec-2017 14:15:21 STScI Edit Number: 0 Title Probing spatially variable Lyman-continuum escape from the brightest lensed galaxy in the universe ------------------------------------------------------------------------------------ Type Cycle GO 25 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Haakon Dahle University of Oslo Y CoI: Dr. Matthew Bayliss Massachusetts Institute of Technology N CoI: Dr. Jane R. Rigby NASA Goddard Space Flight Center N CoI: Prof. Michael D. Gladders University of Chicago N CoI: Prof. Keren Sharon University of Michigan N CoI: Dr. T. Emil Rivera-Thorsen University of Oslo N CoI: Ms. Traci Lin Johnson University of Michigan N CoI: Max Gronke University of Oslo N ------------------------------------------------------------------------------------ Abstract Recent Magellan spectra of a strongly gravitationally lensed starburst galaxy at z=2.4 show clear evidence of direct escape of Lyman-alpha photons through a riddled neutral medium. The observed Lyman-alpha line profile has been theoretically predicted, but never unambiguously seen so far, and it is considered to be a smoking gun for the escape of Lyman-continuum photons from star-forming galaxies. The unique Lyman-alpha line profile, in addition to the unique brightness and apparent angular size of the strongly lensed galaxy, makes it an instantly compelling target for direct detection of LyC photons, utilizing the UV capabilities of HST while they are still available. We propose WFC3/UVIS F275W-band imaging to directly reveal the spatial distribution of the escape of ionizing photons. Coupled with scheduled Cycle 25 HST imaging and grism spectroscopy at longer wavelengths, this will reveal the physical conditions for Lyman continuum leakage, across ~4000 resolution elements at <100pc resolution. ------------------------------------------------------------------------------------ Observations Description ------------------------ We have been allocated 3 orbits for WFC3/UVIS imaging in the F275W filter. We split the allocation into two visits, of two and one orbits, respectively, to improve schedulability. No a priori restriction is given on roll angle, but the roll angle should be the same for both visits. Two exposures are made during each orbit, with dither offsets to ensure that the gap between the chips in a given exposure is always covered by the five other exposures. Postflash of 8 electrons is applied to ensure a background level of 12 electrons to mitigate CTE losses. ------------------------------------------------------------------------------------ 15418( 2) - 13-Dec-2017 14:15:21 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PSZ1G311.65- GALAXY, GRAVITATIONAL RA=15H50M7.0000S, J2000 V = 17.8 +/- 0.1 R=17.82, z=17.38, 18.48 LENS, HIGH REDSHIFT DEC=-78D11'32.00" J=16.75, Ks=15.43 (Vega) GALAXY, STARBURST Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 15418( 2) - 13-Dec-2017 14:15:21 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 2.5 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 2.5 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 15418( 2) - 13-Dec-2017 14:15:21 - [ 4] Visit: 01 Visit Requirements: 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 PSZ1G311.65 WFC3/UVI ACCUM UVIS-FIX F275W FLASH=8 1 1564 S POS TARG 0.0, 0.0; -18.48 S see below PATTERN 1 1 (6318 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 | ------------------------------------------------------------------------------------------------------------------------------------ PSZ1G311.65-18.48 1 WFC3/UVI ACCUM UVIS-FIX F275W 1 none none none 1 1552.0 S S PSZ1G311.65-18.48 1 WFC3/UVI ACCUM UVIS-FIX F275W 2 none none none 1 1552.0 S S PSZ1G311.65-18.48 1 WFC3/UVI ACCUM UVIS-FIX F275W 3 none none none 2 1607.0 S S PSZ1G311.65-18.48 1 WFC3/UVI ACCUM UVIS-FIX F275W 4 none none none 2 1607.0 S S 15418( 2) - 13-Dec-2017 14:15:21 - [ 5] Visit: 02 Visit Requirements: SAME ORIENT AS 01 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 PSZ1G311.65 WFC3/UVI ACCUM UVIS-FIX F275W FLASH=8 1 1564 S POS TARG 0.4, 8; PATTERN -18.48 S see below 2 1 (3104 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 | ------------------------------------------------------------------------------------------------------------------------------------ PSZ1G311.65-18.48 1 WFC3/UVI ACCUM UVIS-FIX F275W 1 none none none 1 1552.0 S S PSZ1G311.65-18.48 1 WFC3/UVI ACCUM UVIS-FIX F275W 2 none none none 1 1552.0 S S 15418( 2) - 13-Dec-2017 14:15:21 - [ 6] Summary Form for Proposal 15418 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=8 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 1, PATTERN 2 1, POS TARG 0.0, 0.0, POS TARG 0.4, 8, SAME ORIENT AS 01 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F275W ------------------------------------------------------------------------------------------------------------------------------------ Target Names PSZ1G311.65-18.48 ------------------------------------------------------------------------------------------------------------------------------------