15467( 2) - 07-Dec-2018 13:02:59 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15467 Version: 2 Check-in Time: 07-Dec-2018 13:02:59 STScI Edit Number: 0 Title The Brightest Lens in the Sky: Stellar Populations on ~50 pc Scales at the Peak Epoch of Star Formation ------------------------------------------------------------------------------------ Type Cycle GO 25 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Dawn K. Erb University of Wisconsin - Milwaukee Y CoI: Dr. Matthew Auger University of Cambridge N CoI: Dr. Bethan Lesley James Space Telescope Science Institute - ESA N CoI: Lindsay Oldham Harvard University N CoI: Prof. Max Pettini University of Cambridge N CoI: Mr. Cameron Lemon University of Cambridge N ------------------------------------------------------------------------------------ Abstract While thousands of galaxies have now been observed at the peak epoch of star formation, only the rare and highly magnified gravitationally lensed sources in conjunction with high resolution HST imaging enable the study of star formation at sub-kpc scales. We propose multiwavelength WFC3 imaging of J1059+4251 at z=2.79, the brightest galaxy-scale gravitational lens discovered to date. With F606W imaging obtained only a month ago, we have discovered that the source is magnified by an extraordinary factor of ~130, with multiple knots of star formation on scales of ~50 pc in the source plane. We therefore now request imaging in three additional filters in order to constrain the stellar populations across the source. These data will enable measurements of the stellar mass surface density, the star formation rate and specific star formation rate, the surface density of star formation, and the age and reddening of the stellar populations, all on ~50 pc spatial scales. With these results we will test models of star formation at high redshift by determining the fraction of the total star formation arising in clumps with sizes << 1 kpc, and relate the properties of the star-forming regions to spectroscopic measurements of galactic outflows in order to determine whether the outflows are locally or globally sourced. The unprecedented brightness of J1059+4251 will make it one of the preeminent laboratories for the study of star formation in the high redshift universe, and high resolution, multiwavelength HST imaging will be an essential component of that work. The scientific returns of these observations will be maximized if they are taken during Cycle 25 via the mid-cycle program. ------------------------------------------------------------------------------------ Observations Description ------------------------ The goal of this program is to obtain multi-band imaging of the bright, gravitationally lensed arc SDSSJ1059+4251. Our primary concern is to optimize the spatial sampling, and we will therefore use a 4-point box dither for the UVIS observations. For the IR observations with larger pixels, we will use a 4-point box dither followed by a 3-point line for a total of 7 exposures at 6 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 15467( 2) - 07-Dec-2018 13:02:59 - [ 2] use the STEP100 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. ------------------------------------------------------------------------------------ 15467( 2) - 07-Dec-2018 13:02:59 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SDSSJ1059+42 GALAXY, GRAVITATIONAL RA=10H59M55.1592S, J2000 V = 19 51 LENS, HIGH REDSHIFT DEC=+42D51'34.16" GALAXY Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 15467( 2) - 07-Dec-2018 13:02:59 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 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: 2 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: 3 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 ------------------------------------------------------------------------------------------------------------------------------------ 15467( 2) - 07-Dec-2018 13:02:59 - [ 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 SDSSJ1059+4 WFC3/UVI ACCUM UVIS1 F814W 1 643 S PATTERN 1 1 251 S (2572 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ1059+4251 1 WFC3/UVI ACCUM UVIS1 F814W 1 none none none 1 N/A S SDSSJ1059+4251 1 WFC3/UVI ACCUM UVIS1 F814W 2 none none none 1 N/A S SDSSJ1059+4251 1 WFC3/UVI ACCUM UVIS1 F814W 3 none none none 1 N/A S SDSSJ1059+4251 1 WFC3/UVI ACCUM UVIS1 F814W 4 none none none 1 N/A S 15467( 2) - 07-Dec-2018 13:02:59 - [ 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 SDSSJ1059+4 WFC3/IR MULTIAC IR F125W NSAMP=10, SAMP-SEQ=STEP100 1 DEF PATTERN 2 1 251 CUM (1596.927 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ1059+4 WFC3/IR MULTIAC IR F125W NSAMP=9, SAMP-SEQ=STEP100 1 DEF PATTERN 3 2 251 CUM (897.694 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ1059+4251 1 WFC3/IR MULTIAC IR F125W 1 none none none 1 N/A CUM SDSSJ1059+4251 1 WFC3/IR MULTIAC IR F125W 2 none none none 1 N/A CUM SDSSJ1059+4251 1 WFC3/IR MULTIAC IR F125W 3 none none none 1 N/A CUM SDSSJ1059+4251 1 WFC3/IR MULTIAC IR F125W 4 none none none 1 N/A CUM SDSSJ1059+4251 2 WFC3/IR MULTIAC IR F125W 1 none none none 1 N/A CUM SDSSJ1059+4251 2 WFC3/IR MULTIAC IR F125W 2 none none none 1 N/A CUM SDSSJ1059+4251 2 WFC3/IR MULTIAC IR F125W 3 none none none 1 N/A CUM 15467( 2) - 07-Dec-2018 13:02:59 - [ 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 SDSSJ1059+4 WFC3/IR MULTIAC IR F160W NSAMP=10, SAMP-SEQ=STEP100 1 DEF PATTERN 2 1 251 CUM (1596.927 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SDSSJ1059+4 WFC3/IR MULTIAC IR F160W NSAMP=9, SAMP-SEQ=STEP100 1 DEF PATTERN 3 2 251 CUM (897.694 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 | ------------------------------------------------------------------------------------------------------------------------------------ SDSSJ1059+4251 1 WFC3/IR MULTIAC IR F160W 1 none none none 1 N/A CUM SDSSJ1059+4251 1 WFC3/IR MULTIAC IR F160W 2 none none none 1 N/A CUM SDSSJ1059+4251 1 WFC3/IR MULTIAC IR F160W 3 none none none 1 N/A CUM SDSSJ1059+4251 1 WFC3/IR MULTIAC IR F160W 4 none none none 1 N/A CUM SDSSJ1059+4251 2 WFC3/IR MULTIAC IR F160W 1 none none none 1 N/A CUM SDSSJ1059+4251 2 WFC3/IR MULTIAC IR F160W 2 none none none 1 N/A CUM SDSSJ1059+4251 2 WFC3/IR MULTIAC IR F160W 3 none none none 1 N/A CUM 15467( 2) - 07-Dec-2018 13:02:59 - [ 8] Summary Form for Proposal 15467 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR, UVIS1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=10, NSAMP=9, SAMP-SEQ=STEP100 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 1, PATTERN 2 1, PATTERN 3 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F125W, F160W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SDSSJ1059+4251 ------------------------------------------------------------------------------------------------------------------------------------