14466( 3) - 14-Dec-2015 16:01:15 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14466 Version: 3 Check-in Time: 14-Dec-2015 16:01:15 STScI Edit Number: 1 Title Lyman Alpha halo in a confirmed Lyman Continuum leaker ------------------------------------------------------------------------------------ Type Cycle GO 23 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Ivana Orlitova Astronomical Institute, Academy of Y Sciences of CR CoI: Dr. Anne Verhamme Observatoire de Geneve N CoI: Dr. Matthew Hayes Stockholm University N CoI: Prof. Daniel Schaerer Observatoire de Geneve N CoI: Dr. Yuri I. Izotov Ukrainian National Academy of Sciences, N MAO CoI: Prof. Trinh X. Thuan The University of Virginia N CoI: Prof. Goeran Oestlin Stockholm University N CoI: Dr. Jens Melinder Stockholm University N CoI: Dr. Natalia G. Guseva Ukrainian National Academy of Sciences, N MAO CoI: Dr. Gabor Worseck Max-Planck-Institut fur Astronomie, N Heidelberg ------------------------------------------------------------------------------------ Abstract The Lyman-alpha (Lya) line is a tool of prime cosmological importance, bright enough to detect galaxies out to extreme redshifts. Spatially resolved studies both at low and high redshift have shown that much of the Lya emission often comes from a diffuse "halo" component extending beyond several galactic radii. The origin of the halos is currently being debated: scattering of Lya radiation produced in star-forming regions, or in situ production of Lya photons. We predict that if the Lya halos are due to scattering of Lya radiation from star-forming regions, then the halos should be missing or weak in galaxies which are transparent to their ionizing Lyman continuum. We have obtained HST time in Cycle 23 to test this hypothesis. At the time of proposal submission, no suitable targets with confirmed Lyman continuum escape were known, we therefore based our classification on their Lya properties. Since then, we have detected Lyman continuum escaping from a compact, star-forming, Green Pea galaxy J0925+1403. In the present proposal, we will image the galaxy in Lya, far-UV continuum, and optical filters in order to probe the extent and radial profile of the Lya halo emission as compared to the other filters. This study will provide a direct test to our predictions, and will complement results of our regular Cycle 23 program GO 14131. ------------------------------------------------------------------------------------ Observations Description ------------------------ This program will image the compact dwarf galaxies J0925+1403 with two ACS/SBC filters to synthesize a Lya bandpass (F150LP and F165LP - 3 orbits), two WFC3/UVIS filters (F475W and F547M - 1 orbit), ACS/WFC F850LP and ACS ramp filter FR853N (1 orbit). This amounts to 5 orbits, organized into 4 visits. 14466( 3) - 14-Dec-2015 16:01:15 - [ 2] The SBC visits should be scheduled so that the SBC HAS NOT BEEN IN USE FOR THE PAST 24 hours to minimize the dark current. We have split the SBC observations into 2 visits to prevent heatup of the detector. The WFC3/UVIS visit utilises a 3 point dither to step over droplets. ACS/WFC is used for ramp filter imaging and F850LP, utilising SMALL pos-targs. Health/safety flag has been raised by the Bright Object Tool (BOT) at ACS/SBC F150LP for a star present in the field of view. It is due to a star at RA=09 25 32.7, DEC=+14 02 40.7 of V=15mag and unknown FUV magnitude. However, its NUV = 20.5 mag, and no warning is issued by the GALEX catalogue. This is proven by the ETC calculation, even if we assume an O5V stellar type (ACS.im.756629). All the other targets present in the field are safe, including the observed galaxy. The same star issues a warning at WFC3 filters to possibly cause a degradation of the science. However, the angular distance between this source and our science target is large (>30"), and the target is compact (1"), therefore we expect no impact. The galaxy that we target is compact (1 arcsec). Our ETC calculations show that the observations are feasible in all the filters, and we attain limiting fluxes appropriate for our scientific goals (for ACS/SBC filters: ACS.im.756748, ACS.im.756749). Central parts of the galaxy are two magnitudes brighter, but will not result in detector saturation. Post-flash values for WFC3/UVIS and ACS/WFC were determined using ETC and were adjusted so as to avoid APT warnings. ------------------------------------------------------------------------------------ 14466( 3) - 14-Dec-2015 16:01:15 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 J0925+1403 GALAXY, DWARF COMPACT, RA=09H25M32.3700S, J2000 Z = V = 20.71 +/- 0.05 FUV=20.71+/-0.05, STARBURST DEC=+14D03'13.06" 0.3012 NUV=20.75+/-0.04 Reference Frame: ICRS Extended: YES ------------------------------------------------------------------------------------------------------------------------------------ 14466( 3) - 14-Dec-2015 16:01:15 - [ 4] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: We request that the SBC not be used 24 hours before this visit in order to mitigate the effects of dark current. The SBC observations are split in two visits to prevent heatup (and associated increase in dark current) of detector. 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 J0925+1403 ACS/SBC ACCUM SBC F150LP 1 742 S (742 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J0925+1403 ACS/SBC ACCUM SBC F165LP 1 2000 S SAME POS AS 1 (2000 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J0925+1403 ACS/SBC ACCUM SBC F165LP 1 2133 S POS TARG (2133 S) -0.5205196687938966, -0.9500606943305857 ------------------------------------------------------------------------------------------------------------------------------------ 4 J0925+1403 ACS/SBC ACCUM SBC F150LP 1 760 S (760 SAME POS AS 3 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0925+1403 1 ACS/SBC ACCUM SBC F150LP none none none none 1 N/A J0925+1403 2 ACS/SBC ACCUM SBC F165LP none none none none 1 N/A J0925+1403 3 ACS/SBC ACCUM SBC F165LP none none none none 2 N/A J0925+1403 4 ACS/SBC ACCUM SBC F150LP none none none none 2 N/A 14466( 3) - 14-Dec-2015 16:01:15 - [ 5] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: We request that the SBC not be used 24 hours before this visit in order to mitigate the effects of dark current. The SBC observations are split in two visits to prevent heatup (and associated increase in dark current) of detector. 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 J0925+1403 ACS/SBC ACCUM SBC F150LP 1 742 S (742 POS TARG S) 0.5842473570133007, 0.9493177058268445 ------------------------------------------------------------------------------------------------------------------------------------ 2 J0925+1403 ACS/SBC ACCUM SBC F165LP 1 2000 S SAME POS AS 1 (2000 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0925+1403 1 ACS/SBC ACCUM SBC F150LP none none none none 1 N/A J0925+1403 2 ACS/SBC ACCUM SBC F165LP none none none none 1 N/A 14466( 3) - 14-Dec-2015 16:01:15 - [ 6] 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 J0925+1403 WFC3/UVI ACCUM UVIS2-C1K F438W FLASH=10 1 300 S (300 GS ACQ SCENARIO BASE1B3 S 1C-SUB S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J0925+1403 WFC3/UVI ACCUM UVIS2-C1K F438W FLASH=10 1 300 S (300 POS TARG 2.9568, 2.9568 S 1C-SUB S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J0925+1403 WFC3/UVI ACCUM UVIS2-C1K F438W FLASH=10 1 300 S (300 POS TARG 5.9136, 5.9136 S 1C-SUB S) ------------------------------------------------------------------------------------------------------------------------------------ 4 J0925+1403 WFC3/UVI ACCUM UVIS2-C1K F547M FLASH=6 1 500 S (500 SAME POS AS 3 S 1C-SUB S) ------------------------------------------------------------------------------------------------------------------------------------ 5 J0925+1403 WFC3/UVI ACCUM UVIS2-C1K F547M FLASH=6 1 500 S (500 SAME POS AS 2 S 1C-SUB S) ------------------------------------------------------------------------------------------------------------------------------------ 6 J0925+1403 WFC3/UVI ACCUM UVIS2-C1K F547M FLASH=6 1 499 S (499 SAME POS AS 1 S 1C-SUB 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0925+1403 1 WFC3/UVI ACCUM UVIS2-C1 F438W none none none none 1 N/A S K1C-SUB J0925+1403 2 WFC3/UVI ACCUM UVIS2-C1 F438W none none none none 1 N/A S K1C-SUB J0925+1403 3 WFC3/UVI ACCUM UVIS2-C1 F438W none none none none 1 N/A S K1C-SUB J0925+1403 4 WFC3/UVI ACCUM UVIS2-C1 F547M none none none none 1 N/A S K1C-SUB J0925+1403 5 WFC3/UVI ACCUM UVIS2-C1 F547M none none none none 1 N/A S K1C-SUB J0925+1403 6 WFC3/UVI ACCUM UVIS2-C1 F547M none none none none 1 N/A S K1C-SUB 14466( 3) - 14-Dec-2015 16:01:15 - [ 7] 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 J0925+1403 ACS/WFC ACCUM WFC1-IRAM FR853N 8542 FLASH=16 1 400 S (400 P S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J0925+1403 ACS/WFC ACCUM WFC1-IRAM FR853N 8542 FLASH=16 1 400 S (400 POS TARG 0.115, 0.125 P S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J0925+1403 ACS/WFC ACCUM WFC1-IRAM FR853N 8542 FLASH=16 1 400 S (400 POS TARG 0.231, 0.259 P S) ------------------------------------------------------------------------------------------------------------------------------------ 4 J0925+1403 ACS/WFC ACCUM WFC F850LP 1 388 S (388 SAME POS AS 3 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 J0925+1403 ACS/WFC ACCUM WFC F850LP 1 388 S (388 SAME POS AS 1 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 | ------------------------------------------------------------------------------------------------------------------------------------ J0925+1403 1 ACS/WFC ACCUM WFC1-IRA FR853N 8542 none none none none 1 N/A MP J0925+1403 2 ACS/WFC ACCUM WFC1-IRA FR853N 8542 none none none none 1 N/A MP J0925+1403 3 ACS/WFC ACCUM WFC1-IRA FR853N 8542 none none none none 1 N/A MP J0925+1403 4 ACS/WFC ACCUM WFC F850LP none none none none 1 N/A J0925+1403 5 ACS/WFC ACCUM WFC F850LP none none none none 1 N/A 14466( 3) - 14-Dec-2015 16:01:15 - [ 8] Summary Form for Proposal 14466 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures SBC, UVIS2-C1K1C-SUB, WFC, WFC1-IRAMP ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/SBC, ACS/WFC, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=10, FLASH=16, FLASH=6 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GS ACQ SCENARIO BASE1B3, POS TARG -0.5205196687938966, -0.9500606943305857, POS TARG 0.115, 0.125, POS TARG 0.231, 0.259, POS TARG 0.5842473570133007, 0.9493177058268445, POS TARG 2.9568, 2.9568, POS TARG 5.9136, 5.9136, SAME POS AS 1, SAME POS AS 2, SAME POS AS 3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F150LP, F165LP, F438W, F547M, F850LP, FR853N ------------------------------------------------------------------------------------------------------------------------------------ Target Names J0925+1403 ------------------------------------------------------------------------------------------------------------------------------------