14632( 5) - 21-Nov-2016 11:55:04 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14632 Version: 5 Check-in Time: 21-Nov-2016 11:55:04 STScI Edit Number: 3 Title Lyman-alpha Imaging at ~20 pc Resolution in a Low Mass Lensed Galaxy at z=1.85 ------------------------------------------------------------------------------------ Type Cycle GO 24 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Dawn K. Erb University of Wisconsin - Milwaukee Y CoI: Dr. Danielle Berg University of Wisconsin - Milwaukee N CoI: Dr. Gabriel Brammer Space Telescope Science Institute - ESA N CoI: Prof. Max Pettini University of Cambridge N ------------------------------------------------------------------------------------ Abstract Because Lyman-alpha photons are resonantly scattered by neutral hydrogen, the strength and spatial extent of Lya emission in galaxies depend on the HI column density and covering fraction, properties that are of primary interest to the escape of ionizing radiation. Lya emission is particularly important to the study of low mass, low metallicity galaxies: such objects are likely to be responsible for the reionization of the universe, and Lya emission is more common in these galaxies. With this proposal, we request 7 orbits of WFC3/UVIS imaging to obtain a high resolution map of Lya emission in the low mass, low metallicity z=1.85 gravitationally lensed galaxy SL2SJ021737-051329. With oxygen abundance <10% of solar, stellar mass <10^8 Msun, and extremely strong Lya emission with rest-frame equivalent width ~120 A, this object is a prime example of a low mass Lya-emitter, and its gravitational magnification by a factor of ~35 results in remarkably high WFC3/UVIS spatial resolution of ~20 pc. Existing HST broadband and IR grism observations will allow us to compare the spatial extent of the Lya emission with both the rest-frame UV continuum and the rest-frame optical nebular line emission, in order to map the resonant scattering of Lya photons from their origin in star-forming regions, obtain constraints on the location of the scattering gas, and relate this information to the kinematics and geometry of the galaxy. The proposed observations, in combination with the spectroscopic information we have already obtained, will provide the most comprehensive and highest resolution picture of Lya emission at z > 1 to date. ------------------------------------------------------------------------------------ Observations Description ------------------------ The goal of this proposal is to obtain a narrow-band Lya image of a gravitationally lensed galaxy at z=1.85 using the WFC3 UVIS F343N filter. We will observe the galaxy in the F343N filter for 6 orbits, and in the F390M filter for 1 orbit in order to obtain an off-line continuum image. For all observations we use the UVIS-C1K1C-CTE aperture in order to place the target near one of the amplifiers in order to minimize CTE effects. Observations are divided into 4 visits. Visits 1-3 are identical and contain the F343N observations, with 2 orbits per visit. We use the WFC3-UVIS-DITHER-LINE pattern for two exposures per orbit, and include 10 e- FLASH based on the expectation of ~2 e- from sky+dark in ~1400 sec. 14632( 5) - 21-Nov-2016 11:55:04 - [ 2] Visit 4 contains the F390M observations. We again use the WFC3-UVIS-DITHER-LINE pattern for two exposures per orbit. We include 9 e- FLASH based on the expectation of ~3 e- from sky+dark in ~1400 sec. All visits are constrained to have the same ORIENT (SAME ORIENT AS Visit 01) in order to maximize image alignment and overlap between exposures for image registration. ------------------------------------------------------------------------------------ 14632( 5) - 21-Nov-2016 11:55:04 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SL2SJ021737- GALAXY, ELLIPTICAL, RA=02H17M37.2370S, J2000 V = 22.07 051329 GRAVITATIONAL LENS, DEC=-05D13'29.78" HIGH REDSHIFT GALAXY Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 14632( 5) - 21-Nov-2016 11:55:04 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.145 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 14632( 5) - 21-Nov-2016 11:55:04 - [ 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 SL2SJ021737 WFC3/UVI ACCUM UVIS2-C1K F343N FLASH=10 2 1360 S GS ACQ SCENARIO BASE1B3; -051329 S 1C-CTE see below PATTERN 1 1 (5586 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 | ------------------------------------------------------------------------------------------------------------------------------------ SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F343N 1 none 1 none 1 1369.0 S S K1C-CTE SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F343N 1 none 2 none 1 1369.0 S S K1C-CTE SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F343N 2 none 1 none 2 1424.0 S S K1C-CTE SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F343N 2 none 2 none 2 1424.0 S S K1C-CTE 14632( 5) - 21-Nov-2016 11:55:04 - [ 6] 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 SL2SJ021737 WFC3/UVI ACCUM UVIS2-C1K F343N FLASH=10 2 1360 S GS ACQ SCENARIO BASE1B3; -051329 S 1C-CTE see below PATTERN 1 1 (5586 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 | ------------------------------------------------------------------------------------------------------------------------------------ SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F343N 1 none 1 none 1 1369.0 S S K1C-CTE SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F343N 1 none 2 none 1 1369.0 S S K1C-CTE SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F343N 2 none 1 none 2 1424.0 S S K1C-CTE SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F343N 2 none 2 none 2 1424.0 S S K1C-CTE 14632( 5) - 21-Nov-2016 11:55:04 - [ 7] Visit: 03 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 SL2SJ021737 WFC3/UVI ACCUM UVIS2-C1K F343N FLASH=10 2 1360 S GS ACQ SCENARIO BASE1B3; -051329 S 1C-CTE see below PATTERN 1 1 (5586 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 | ------------------------------------------------------------------------------------------------------------------------------------ SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F343N 1 none 1 none 1 1369.0 S S K1C-CTE SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F343N 1 none 2 none 1 1369.0 S S K1C-CTE SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F343N 2 none 1 none 2 1424.0 S S K1C-CTE SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F343N 2 none 2 none 2 1424.0 S S K1C-CTE 14632( 5) - 21-Nov-2016 11:55:04 - [ 8] Visit: 04 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 SL2SJ021737 WFC3/UVI ACCUM UVIS2-C1K F390M FLASH=9 1 1360 S GS ACQ SCENARIO BASE1B3; -051329 S 1C-CTE see below PATTERN 1 1 (2738 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 | ------------------------------------------------------------------------------------------------------------------------------------ SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F390M 1 none none none 1 1369.0 S S K1C-CTE SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F390M 2 none none none 1 1369.0 S S K1C-CTE 14632( 5) - 21-Nov-2016 11:55:04 - [ 9] Visit: 52 Visit Requirements: ORIENT 355D TO 35 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 SL2SJ021737 WFC3/UVI ACCUM UVIS2-C1K F343N FLASH=10 2 1360 S POS TARG 0.099, 0.106; -051329 S 1C-CTE see below GS ACQ SCENARIO BASE1B3 (2738 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 | ------------------------------------------------------------------------------------------------------------------------------------ SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F343N none none 1 none 1 1369.0 S S K1C-CTE SL2SJ021737-051329 1 WFC3/UVI ACCUM UVIS2-C1 F343N none none 2 none 1 1369.0 S S K1C-CTE 14632( 5) - 21-Nov-2016 11:55:04 - [ 10] Summary Form for Proposal 14632 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS2-C1K1C-CTE ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=10, FLASH=9 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GS ACQ SCENARIO BASE1B3, ORIENT 355D TO 35 D, PATTERN 1 1, POS TARG 0.099, 0.106, SAME ORIENT AS 01 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F343N, F390M ------------------------------------------------------------------------------------------------------------------------------------ Target Names SL2SJ021737-051329 ------------------------------------------------------------------------------------------------------------------------------------