16876( 2) - 14-Dec-2021 19:43:05 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16876 Version: 2 Check-in Time: 14-Dec-2021 19:43:05 STScI Edit Number: 0 Title Unveiling the Source of Extreme Ionization in a Lensed Galaxy at z=2.6 ------------------------------------------------------------------------------------ Type Cycle GO 29 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Dawn K. Erb University of Wisconsin - Milwaukee Y CoI: Dr. Matthew Auger University of Cambridge N CoI: Dr. Danielle Berg University of Texas at Austin N CoI: Dr. Annalisa Citro University of Wisconsin - Milwaukee N CoI: Dr. Bethan Lesley James Space Telescope Science Institute - ESA - N JWST CoI: Prof. Max Pettini University of Cambridge N ------------------------------------------------------------------------------------ Abstract Studies of the most highly ionized galaxies in the universe offer insights into the complex interplay between feedback, shocks, and radiative cooling, driven by extreme star formation or accreting supermassive black holes. We here propose eight orbits of broad and narrowband imaging of J1356-2313, a puzzling, newly discovered gravitationally lensed source at z=2.6 with the highly unusual combination of extreme high ionization UV line emission from O VI, N V, He II and C IV coupled with damped Lya absorption. Integral field spectroscopy of the kinematically narrow O VI emission reveals that it is gravitationally lensed into an arc, indicating a spatially extended source larger than an AGN narrow-line region; further, the line is kinematically inconsistent with a quasar outflow. The very high ionization emission lines may instead be a signature of catastrophic radiative cooling, which may suppress feedback in the most extreme starbursts. With the proposed broadband imaging, we will construct a lensing model and determine the intrinsic luminosity of the source and the structure of the emitting region(s). Modeling of the spectral energy distribution will offer further constraints on the nature of the ionizing source. We also propose narrowband imaging of the extremely strong and spatially extended O VI emission, which is fortuitously redshifted into the F373N filter. The spatial resolution of HST in combination with the magnification of gravitational lensing will provide an unprecedented map of extremely high ionization line emission in the distant universe, allowing tests of the emission mechanisms discussed above. ------------------------------------------------------------------------------------ Observations Description ------------------------ The goal of this proposal is to use WFC3-UVIS/IR to obtain both broad (F606W, F814W, F125W, F160W) and narrow/medium-band (F373N and F390M) imaging of the gravitationally lensed galaxy J1356-2313. The program consists of 8 orbits, two in each of the narrow/medium filters and one in each of the broadband filters. Observations with each filter are configured as separate visits, so we have a total of six visits: two 2-orbit visits and four visits with one orbit each. 16876( 2) - 14-Dec-2021 19:43:05 - [ 2] For the F373N and F390M imaging we divide each orbit into three exposures using the UVIS-DITHER-LINE-3PT pattern, balancing considerations of cosmic ray rejection with the changes in efficiency, background and S/N from increasing the number of exposures. We mitigate CTE effects by using the UVIS-C1K1C-CTE aperture in order to place the target near one of the amplifiers, and further specify FLASH=16 in order to reach the recommended background level of 20 e-, based on calculations with the ETC. We also use the UVIS-C1K1C-CTE aperture for the broadband F606W and F814W observations. With one orbit and visit per filter, we divide these observations into four exposures per orbit with the UVIS-DITHER-BOX pattern in order to enable rejection of cosmic rays and detector artifacts. For the F814W observations the ETC predicts 19 background e-, and we therefore add FLASH=1 to reach the recommended level of 20. Note that this differs from the APT background prediction, which is lower and therefore recommends more FLASH. As advised by the APT warning, we use the ETC predictions. For the IR observations in F125W and F160W with larger pixels, we use a 4-point box dither followed by a 3-point line for a total of seven exposures at six different positions. The repeated position, corresponding to the first exposure in each dither pattern, will enable a consistency check of the slightly different exposure times of the two patterns, and the combination of the two patterns will improve the sub-pixel sampling over either pattern alone. We will use the STEP50 sampling sequence in order to obtain good sampling on both the lensed arc and on PSF stars to be used for the de-lensing model. The dither sequences will also enable rejection of detector artifacts and cosmic rays, and the seven exposures with two different exposure times enable the most efficient use of the full orbit. This program has no constraints on the roll angle or on the time of observations, so there are no specific impacts of reduced gyro operations. ------------------------------------------------------------------------------------ 16876( 2) - 14-Dec-2021 19:43:05 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 J1356-2313 GALAXY, EINSTEIN RING, RA=13H56M51.8760S, J2000 V = 20.5 GRAVITATIONAL LENS, DEC=-23D13'18.54" HIGH REDSHIFT GALAXY Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 16876( 2) - 14-Dec-2021 19:43:05 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 5 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE-3PT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.135 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-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.173 Line_Spacing 0.112 Coordinate_Frame POS-TARG Pattern_Orient 23.884 Angle_Between_Sides 81.785 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-BOX-MIN Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.572 Line_Spacing 0.365 Coordinate_Frame POS-TARG Pattern_Orient 18.528 Angle_Between_Sides 74.653 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 4 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-LINE-3PT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.605 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 41.788 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 16876( 2) - 14-Dec-2021 19:43:05 - [ 5] 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 J1356-2313 WFC3/UVI ACCUM UVIS2-C1K F373N FLASH=16 1 800 S PATTERN 5 1-2 S 1C-CTE see below (2487 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1356-2313 WFC3/UVI ACCUM UVIS2-C1K F373N FLASH=16 1 800 S S 1C-CTE see below (2484 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1356-2313 1 WFC3/UVI ACCUM UVIS2-C1 F373N 1 none none none 1 830.0 S S K1C-CTE J1356-2313 1 WFC3/UVI ACCUM UVIS2-C1 F373N 2 none none none 1 830.0 S S K1C-CTE J1356-2313 1 WFC3/UVI ACCUM UVIS2-C1 F373N 3 none none none 2 827.0 S S K1C-CTE J1356-2313 2 WFC3/UVI ACCUM UVIS2-C1 F373N 1 none none none 1 830.0 S S K1C-CTE J1356-2313 2 WFC3/UVI ACCUM UVIS2-C1 F373N 2 none none none 2 827.0 S S K1C-CTE J1356-2313 2 WFC3/UVI ACCUM UVIS2-C1 F373N 3 none none none 2 827.0 S S K1C-CTE 16876( 2) - 14-Dec-2021 19:43:05 - [ 6] Visit: 02 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 J1356-2313 WFC3/UVI ACCUM UVIS2-C1K F390M FLASH=16 1 800 S PATTERN 5 1-2 S 1C-CTE see below (2487 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1356-2313 WFC3/UVI ACCUM UVIS2-C1K F390M FLASH=16 1 800 S S 1C-CTE see below (2484 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1356-2313 1 WFC3/UVI ACCUM UVIS2-C1 F390M 1 none none none 1 830.0 S S K1C-CTE J1356-2313 1 WFC3/UVI ACCUM UVIS2-C1 F390M 2 none none none 1 830.0 S S K1C-CTE J1356-2313 1 WFC3/UVI ACCUM UVIS2-C1 F390M 3 none none none 2 827.0 S S K1C-CTE J1356-2313 2 WFC3/UVI ACCUM UVIS2-C1 F390M 1 none none none 1 830.0 S S K1C-CTE J1356-2313 2 WFC3/UVI ACCUM UVIS2-C1 F390M 2 none none none 2 827.0 S S K1C-CTE J1356-2313 2 WFC3/UVI ACCUM UVIS2-C1 F390M 3 none none none 2 827.0 S S K1C-CTE 16876( 2) - 14-Dec-2021 19:43:05 - [ 7] Visit: 03 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 J1356-2313 WFC3/UVI ACCUM UVIS2-C1K F606W 1 500 S PATTERN 2 1 S 1C-CTE see below (2380 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1356-2313 1 WFC3/UVI ACCUM UVIS2-C1 F606W 1 none none none 1 595.0 S S K1C-CTE J1356-2313 1 WFC3/UVI ACCUM UVIS2-C1 F606W 2 none none none 1 595.0 S S K1C-CTE J1356-2313 1 WFC3/UVI ACCUM UVIS2-C1 F606W 3 none none none 1 595.0 S S K1C-CTE J1356-2313 1 WFC3/UVI ACCUM UVIS2-C1 F606W 4 none none none 1 595.0 S S K1C-CTE 16876( 2) - 14-Dec-2021 19:43:05 - [ 8] Visit: 04 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 J1356-2313 WFC3/UVI ACCUM UVIS2-C1K F814W FLASH=1 1 592 S PATTERN 2 1 S 1C-CTE (2368 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1356-2313 1 WFC3/UVI ACCUM UVIS2-C1 F814W 1 none none none 1 N/A S K1C-CTE J1356-2313 1 WFC3/UVI ACCUM UVIS2-C1 F814W 2 none none none 1 N/A S K1C-CTE J1356-2313 1 WFC3/UVI ACCUM UVIS2-C1 F814W 3 none none none 1 N/A S K1C-CTE J1356-2313 1 WFC3/UVI ACCUM UVIS2-C1 F814W 4 none none none 1 N/A S K1C-CTE 16876( 2) - 14-Dec-2021 19:43:05 - [ 9] Visit: 05 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 J1356-2313 WFC3/IR MULTIAC IR F125W NSAMP=10, SAMP-SEQ=STEP50 1 DEF PATTERN 3 1 CUM (996.928 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1356-2313 WFC3/IR MULTIAC IR F125W NSAMP=14, SAMP-SEQ=STEP50 1 DEF PATTERN 4 2 CUM (1347.702 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1356-2313 1 WFC3/IR MULTIAC IR F125W 1 none none none 1 N/A CUM J1356-2313 1 WFC3/IR MULTIAC IR F125W 2 none none none 1 N/A CUM J1356-2313 1 WFC3/IR MULTIAC IR F125W 3 none none none 1 N/A CUM J1356-2313 1 WFC3/IR MULTIAC IR F125W 4 none none none 1 N/A CUM J1356-2313 2 WFC3/IR MULTIAC IR F125W 1 none none none 1 N/A CUM J1356-2313 2 WFC3/IR MULTIAC IR F125W 2 none none none 1 N/A CUM J1356-2313 2 WFC3/IR MULTIAC IR F125W 3 none none none 1 N/A CUM 16876( 2) - 14-Dec-2021 19:43:05 - [ 10] Visit: 06 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 J1356-2313 WFC3/IR MULTIAC IR F160W NSAMP=10, SAMP-SEQ=STEP50 1 DEF PATTERN 3 1 CUM (996.928 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1356-2313 WFC3/IR MULTIAC IR F160W NSAMP=14, SAMP-SEQ=STEP50 1 DEF PATTERN 4 2 CUM (1347.702 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1356-2313 1 WFC3/IR MULTIAC IR F160W 1 none none none 1 N/A CUM J1356-2313 1 WFC3/IR MULTIAC IR F160W 2 none none none 1 N/A CUM J1356-2313 1 WFC3/IR MULTIAC IR F160W 3 none none none 1 N/A CUM J1356-2313 1 WFC3/IR MULTIAC IR F160W 4 none none none 1 N/A CUM J1356-2313 2 WFC3/IR MULTIAC IR F160W 1 none none none 1 N/A CUM J1356-2313 2 WFC3/IR MULTIAC IR F160W 2 none none none 1 N/A CUM J1356-2313 2 WFC3/IR MULTIAC IR F160W 3 none none none 1 N/A CUM 16876( 2) - 14-Dec-2021 19:43:05 - [ 11] Summary Form for Proposal 16876 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR, UVIS2-C1K1C-CTE ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=1, FLASH=16, NSAMP=10, NSAMP=14, SAMP-SEQ=STEP50 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 2 1, PATTERN 3 1, PATTERN 4 2, PATTERN 5 1-2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F125W, F160W, F373N, F390M, F606W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names J1356-2313 ------------------------------------------------------------------------------------------------------------------------------------