14200( 5) - 11-Jan-2016 17:51:30 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14200 Version: 5 Check-in Time: 11-Jan-2016 17:51:30 STScI Edit Number: 0 Title Revealing the host galaxy of a strong Milky Way-type 2175 Angstrom absorber at z = 2.12 ------------------------------------------------------------------------------------ Type Cycle GO 23 ------------------------------------------------------------------------------------ Investigators Contact? PI: Ms. Jingzhe Ma University of Florida Y CoI: Prof. Jian Ge University of Florida N CoI: Dr. Britt Lundgren University of Wisconsin - Madison N CoI: Dr. Jason X. Prochaska University of California - Santa Cruz N ------------------------------------------------------------------------------------ Abstract We propose WFC3/IR G141 grism and F140W direct imaging observations (3 orbits) of a strong Milky Way-type 2175 Angstrom absorbing galaxy at z = 2.12 in the quasar spectrum towards QSO J1211+0833 from the Sloan Digital Sky Survey (SDSS). We conducted follow up observations with the Echelle Spectrograph and Imager (ESI) onboard the Keck-II telescope and the Ultraviolet and Visual Echelle Spectrograph (UVES) on the VLT. Given the simultaneous presence of C I, CO, and the 2175 Angstrom bump, combined with the high metallicity, high dust depletion level and overall low ionization state of the gas, J1211+0833 supports the scenario that the presence of the bump requires an evolved stellar population. We speculate that the host of the J1211+0833 2175 Angstrom bump is likely to be an evolved and chemically-enriched disk galaxy. The proposed observations will enable us to, for the first time, study the properties (morphology, impact parameter, star formation rate, stellar mass) of the host galaxy of a 2175 Angstrom absorber beyond the local Universe, which our existing observational data cannot provide. This population may be used as unique tracers of chemical enrichment and star-forming galaxies at high-redshift. ------------------------------------------------------------------------------------ Observations Description ------------------------ We aim to obtain two-dimensional grism spectra with the WFC3/G141 grism and direct imaging at F140W for wavelength calibration. We will be able to confirm the host galaxy of the absorber using the H-beta and O[III] emission lines. We schedule 3 visits, one visit per orbit. In each orbit/visit, 2 dithered exposures in WFC3/G141 and corresponding direct images at the same position will be taken in the order of direct imaging-> grism->offset->direct imaging->grism. We use POS-TARG offsets to enable rejection of hot/bad pixels and to improve sampling of the PSF. The pattern is: POS-TARG: (0, 0) (1.355, 0.424) pixels: (0, 0) (10.0, 3.5) This is a larger version of the standard WFC3-IR-DITHER-BOX-MIN pattern, which has only 1-2 pixel offsets between pointings. As some bad pixels come in clumps we prefer a slightly larger pattern. No attempt is made to dither over the "dead spot", as large dithers introduce large differential distortion 14200( 5) - 11-Jan-2016 17:51:30 - [ 2] We place no orientation requirements on the first visit to the field. We require the roll angle (i.e. ORIENT) for the second and third visits differ from that of the previous visit by 20 and 160 degrees. The purpose of using different roll angles is to improve our ability to account for contamination by overlapping spectra. ------------------------------------------------------------------------------------ 14200( 5) - 11-Jan-2016 17:51:30 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 J1211+0833 GALAXY, QUASAR RA=12H11M43.4200S, J2000 Z = V = 19.5 +/- 0.1 DEC=+08D33'49.71" 2.1166 Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 14200( 5) - 11-Jan-2016 17:51:30 - [ 4] Visit: 01 Visit Requirements: ORIENT 248D TO 251 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 J1211+0833 WFC3/IR MULTIAC GRISM1024 F140W SAMP-SEQ=SPARS50, NSAMP=5 1 DEF POS TARG 0.0, 0.0 CUM (202.934 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1211+0833 WFC3/IR MULTIAC GRISM1024 G141 SAMP-SEQ=SPARS100, NSAMP=12 1 DEF SAME POS AS 1 CUM (1102.936 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1211+0833 WFC3/IR MULTIAC GRISM1024 F140W SAMP-SEQ=SPARS50, NSAMP=6 1 DEF POS TARG 1.355, 0.424 CUM (252.935 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 J1211+0833 WFC3/IR MULTIAC GRISM1024 G141 SAMP-SEQ=SPARS100, NSAMP=12 1 DEF SAME POS AS 3 CUM (1102.936 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1211+0833 1 WFC3/IR MULTIAC GRISM102 F140W none none none none 1 N/A CUM 4 J1211+0833 2 WFC3/IR MULTIAC GRISM102 G141 none none none none 1 N/A CUM 4 J1211+0833 3 WFC3/IR MULTIAC GRISM102 F140W none none none none 1 N/A CUM 4 J1211+0833 4 WFC3/IR MULTIAC GRISM102 G141 none none none none 1 N/A CUM 4 14200( 5) - 11-Jan-2016 17:51:30 - [ 5] 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 J1211+0833 WFC3/IR MULTIAC GRISM1024 F140W SAMP-SEQ=SPARS50, NSAMP=5 1 DEF POS TARG 0.0, 0.0 CUM (202.934 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1211+0833 WFC3/IR MULTIAC GRISM1024 G141 SAMP-SEQ=SPARS100, NSAMP=12 1 DEF SAME POS AS 1 CUM (1102.936 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1211+0833 WFC3/IR MULTIAC GRISM1024 F140W SAMP-SEQ=SPARS50, NSAMP=6 1 DEF POS TARG 1.355, 0.424 CUM (252.935 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 J1211+0833 WFC3/IR MULTIAC GRISM1024 G141 SAMP-SEQ=SPARS100, NSAMP=12 1 DEF SAME POS AS 3 CUM (1102.936 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1211+0833 1 WFC3/IR MULTIAC GRISM102 F140W none none none none 1 N/A CUM 4 J1211+0833 2 WFC3/IR MULTIAC GRISM102 G141 none none none none 1 N/A CUM 4 J1211+0833 3 WFC3/IR MULTIAC GRISM102 F140W none none none none 1 N/A CUM 4 J1211+0833 4 WFC3/IR MULTIAC GRISM102 G141 none none none none 1 N/A CUM 4 14200( 5) - 11-Jan-2016 17:51:30 - [ 6] Visit: 03 Visit Requirements: ORIENT 20D TO 160D FROM 02 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 J1211+0833 WFC3/IR MULTIAC GRISM1024 F140W SAMP-SEQ=SPARS50, NSAMP=5 1 DEF POS TARG 0.0, 0.0 CUM (202.934 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 J1211+0833 WFC3/IR MULTIAC GRISM1024 G141 SAMP-SEQ=SPARS100, NSAMP=12 1 DEF SAME POS AS 1 CUM (1102.936 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 J1211+0833 WFC3/IR MULTIAC GRISM1024 F140W SAMP-SEQ=SPARS50, NSAMP=6 1 DEF POS TARG 1.355, 0.424 CUM (252.935 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 J1211+0833 WFC3/IR MULTIAC GRISM1024 G141 SAMP-SEQ=SPARS100, NSAMP=12 1 DEF SAME POS AS 3 CUM (1102.936 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 | ------------------------------------------------------------------------------------------------------------------------------------ J1211+0833 1 WFC3/IR MULTIAC GRISM102 F140W none none none none 1 N/A CUM 4 J1211+0833 2 WFC3/IR MULTIAC GRISM102 G141 none none none none 1 N/A CUM 4 J1211+0833 3 WFC3/IR MULTIAC GRISM102 F140W none none none none 1 N/A CUM 4 J1211+0833 4 WFC3/IR MULTIAC GRISM102 G141 none none none none 1 N/A CUM 4 14200( 5) - 11-Jan-2016 17:51:30 - [ 7] Summary Form for Proposal 14200 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures GRISM1024 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=12, NSAMP=5, NSAMP=6, SAMP-SEQ=SPARS100, SAMP-SEQ=SPARS50 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 20D TO 160D FROM 02, ORIENT 248D TO 251 D, POS TARG 0.0, 0.0, POS TARG 1.355, 0.424, SAME POS AS 1, SAME POS AS 3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F140W, G141 ------------------------------------------------------------------------------------------------------------------------------------ Target Names J1211+0833 ------------------------------------------------------------------------------------------------------------------------------------