17286( 4) - 03-Feb-2023 17:26:46 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17286 Version: 4 Check-in Time: 03-Feb-2023 17:26:46 STScI Edit Number: 1 Title Unveiling the origin and nature of the UV-brightest Lyman continuum emitting star-forming galaxy ------------------------------------------------------------------------------------ Type Cycle GO 30 ------------------------------------------------------------------------------------ Investigators Contact? PI: Rui Marques-Chaves University of Geneva, Department of Y Astronomy CoI: Prof. Daniel Schaerer University of Geneva, Department of N Astronomy CoI: Prof. John Chisholm University of Texas at Austin N CoI: Ankur Upadhyaya University of Geneva, Department of N Astronomy CoI: Dr. Floriane Leclercq University of Texas at Austin N ------------------------------------------------------------------------------------ Abstract J1316+2614 at z=3.613 was recently discovered as the UV-brightest star-forming galaxy and also the strongest Lyman continuum (LyC, with energies >13.6 eV) emitter ever detected. 1316+2614 also shows other outstanding properties, including possible "exotic" stellar populations and massive inflowing gas, hinting at a new, very efficient mode of star formation. These unexpected results challenge our understanding of the LyC escape in UV-bright galaxies, and of the potential role these sources may play in cosmic reionization. Furthermore, unsually bright galaxies are now being discovered at very high-redshifts with the James Webb, stressing the need to urgently understand the nature of such sources. The exceptional properties of J1316+2614 call for rapid follow-up observations. Here we request Hubble Space Telescope high-resolution imaging of J1316+2614 for the morphological characterization of the LyC emitting regions, ionizing source, inflowing gas, and the elusive old stellar population. The requested observations will uncover some of the most important, but still open questions raised by this exceptional source, including those related to its origin and nature. ------------------------------------------------------------------------------------ Observations Description ------------------------ This program uses four different filters to obtain rest-frame UV emission (ionizing and non-ionizing emission with the WFC3/UVIS F410M and F775W filters, respectively), map the LyA emission (with the ACS/WFC ramp filter FR551N), and rest-optical emission (WFC3/IR F160W) of a bright Lyman continuum emitter at z=3.613. F410M observations (2 orbits, 1 visit) use a dither-line pattern with 6 points for cosmic rays removal. A post-flash of 14e- is required to reach a sufficient background level. For F775W (1 orbit) we use the standard 4-point box pattern. F775W requires a post-flash of 6e- due to 4 exposures in the 1 orbit to obtain a very clean image. FR551N (1 orbit) uses a standard 4-point box pattern, but no post-flash is required in this case. The central wavelength of FR551N is set 17286( 4) - 03-Feb-2023 17:26:46 - [ 2] to 5604\AA (LyA emission at z=3.613). F160W (1 orbit) uses also the standard 4-point box pattern. For WFC3/UVIS F775W, the target is placed at Aperture='UVIS'. For WFC3/UVIS F410M the target is placed at Aperture='UVIS-C1K1C-CTE' with a specific orient range to avoid placing a bright star on the detector.For WFC3/IR F160W we use Aperture='IR' without any special requirement for orientation. ------------------------------------------------------------------------------------ 17286( 4) - 03-Feb-2023 17:26:46 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 J1316 GALAXY, HIGH REDSHIFT RA=13H16M29.6100S, J2000 Z = V = 21.2 +/- 0.10 R=21.2 GALAXY DEC=+26D14'7.05" 3.613 Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 17286( 4) - 03-Feb-2023 17:26:46 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 6 Point_Spacing 0.145 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 ACS-WFC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.2637 Line_Spacing 0.1856 Coordinate_Frame POS-TARG Pattern_Orient 20.7 Angle_Between_Sides 69.02 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 4 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 1.5 Line_Spacing 1.5 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 1.75 Line_Spacing 1.75 Coordinate_Frame POS-TARG Pattern_Orient 18.528 Angle_Between_Sides 74.653 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 17286( 4) - 03-Feb-2023 17:26:46 - [ 5] Visit: 01 (F410M) Visit Requirements: ORIENT 31D TO 320 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 J1316 WFC3/UVI ACCUM UVIS2-C1K F410M FLASH=14 1 834 S PATTERN 1 1 S 1C-CTE (5004 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1316 1 WFC3/UVI ACCUM UVIS2-C1 F410M 1 none none none 1 N/A S K1C-CTE J1316 1 WFC3/UVI ACCUM UVIS2-C1 F410M 2 none none none 1 N/A S K1C-CTE J1316 1 WFC3/UVI ACCUM UVIS2-C1 F410M 3 none none none 1 N/A S K1C-CTE J1316 1 WFC3/UVI ACCUM UVIS2-C1 F410M 4 none none none 2 N/A S K1C-CTE J1316 1 WFC3/UVI ACCUM UVIS2-C1 F410M 5 none none none 2 N/A S K1C-CTE J1316 1 WFC3/UVI ACCUM UVIS2-C1 F410M 6 none none none 2 N/A S K1C-CTE 17286( 4) - 03-Feb-2023 17:26:46 - [ 6] Visit: 03 (FR551N) 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 J1316 ACS/WFC ACCUM WFC1-IRAM FR551N 5604 1 522 S PATTERN 2 1 P (2088 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1316 1 ACS/WFC ACCUM WFC1-IRA FR551N 5604 1 none none none 1 N/A MP J1316 1 ACS/WFC ACCUM WFC1-IRA FR551N 5604 2 none none none 1 N/A MP J1316 1 ACS/WFC ACCUM WFC1-IRA FR551N 5604 3 none none none 1 N/A MP J1316 1 ACS/WFC ACCUM WFC1-IRA FR551N 5604 4 none none none 1 N/A MP 17286( 4) - 03-Feb-2023 17:26:46 - [ 7] Visit: 04 (F775W) 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 J1316 WFC3/UVI ACCUM UVIS F775W FLASH=6 1 593 S PATTERN 4 1 S (2372 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1316 1 WFC3/UVI ACCUM UVIS F775W 1 none none none 1 N/A S J1316 1 WFC3/UVI ACCUM UVIS F775W 2 none none none 1 N/A S J1316 1 WFC3/UVI ACCUM UVIS F775W 3 none none none 1 N/A S J1316 1 WFC3/UVI ACCUM UVIS F775W 4 none none none 1 N/A S 17286( 4) - 03-Feb-2023 17:26:46 - [ 8] Visit: 05 (F160W) 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 J1316 WFC3/IR MULTIAC IR F160W NSAMP=13, SAMP-SEQ=SPARS50 1 DEF PATTERN 3 1 CUM (2411.751 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1316 1 WFC3/IR MULTIAC IR F160W 1 none none none 1 N/A CUM J1316 1 WFC3/IR MULTIAC IR F160W 2 none none none 1 N/A CUM J1316 1 WFC3/IR MULTIAC IR F160W 3 none none none 1 N/A CUM J1316 1 WFC3/IR MULTIAC IR F160W 4 none none none 1 N/A CUM 17286( 4) - 03-Feb-2023 17:26:46 - [ 9] Summary Form for Proposal 17286 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR, UVIS, UVIS2-C1K1C-CTE, WFC1-IRAMP ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=14, FLASH=6, NSAMP=13, SAMP-SEQ=SPARS50 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 31D TO 320 D, PATTERN 1 1, PATTERN 2 1, PATTERN 3 1, PATTERN 4 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F160W, F410M, F775W, FR551N ------------------------------------------------------------------------------------------------------------------------------------ Target Names J1316 ------------------------------------------------------------------------------------------------------------------------------------