16038( 4) - 07-Nov-2019 14:33:34 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16038 Version: 4 Check-in Time: 07-Nov-2019 14:33:34 STScI Edit Number: 0 Title Imaging a Rare Starburst Central Galaxy in a Merging Cluster ------------------------------------------------------------------------------------ Type Cycle GO 27 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Michael A. McDonald Massachusetts Institute of Technology Y CoI: Mr. Taweewat Somboonpanyakul Massachusetts Institute of Technology N ------------------------------------------------------------------------------------ Abstract We have recently discovered a new galaxy cluster at z=0.48 that harbors a massive central galaxy forming stars at a rate of ~150 Msun/yr. This would make it the second most star-forming central galaxy known and a far cry from the typical red-and-dead giant ellipticals that live in the centers of clusters. While star formation has been seen in the centers of relaxed, cool core clusters -- thought to be a residual cooling flow that represents the imbalance between cooling and feedack -- this system represents the only known system at z<1 where star formation is proceeding in the center of a merging galaxy cluster. It is unclear how such a system could come to be, as the current understanding is that relaxedness is a necessary condition for the development of cooling in the intracluster medium. With the proposed-for HST data, we will be able to map out the ongoing star formation and see if it is morphologically more similar to the distribution of cooling intracluster gas or to nearby member galaxies. This will allow us to distinguish between a merger and cooling origin for the star formation. In either case, this system represents a rare phase of galaxy formation, and may provide important clues to the formation of giant elliptical galaxies and the cooling/feedback balance in cluster cores. ------------------------------------------------------------------------------------ Observations Description ------------------------ The goal of this program is to obtain broadband images in F550M and F110W to probe the young and old stellar populations, respectively. In each filter we will obtain 3 exposures to allow removal of cosmic rays. Overall it should be a really straightforward program to execute. We are only interested in the ~15" surrounding our pointing position, so orientation is not important. ------------------------------------------------------------------------------------ 16038( 4) - 07-Nov-2019 14:33:34 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 CHIPS1911+44 GALAXY, COOLING FLOW, RA=19H11M1.9161S, J2000 V = 19 55 ELLIPTICAL, EMISSION DEC=+44D55'20.73" LINE NEBULA, STARBURST, TIDAL TAIL Reference Frame: ICRS Extended: YES ------------------------------------------------------------------------------------------------------------------------------------ 16038( 4) - 07-Nov-2019 14:33:34 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 3.034 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 85.29 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-BLOB WFC3-IR-DITHER-LINE Pattern_Purpose DITHER DITHER Number_Of_Points 2 2 Point_Spacing 5.183 5.183 Line_Spacing Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 41.859 131.859 Angle_Between_Sides Center_Pattern YES YES ------------------------------------------------------------------------------------------------------------------------------------ 16038( 4) - 07-Nov-2019 14:33:34 - [ 4] Visit: 01 (Blue_cont) 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 CHIPS1911+4 ACS/WFC ACCUM WFC1 F550M 1 100 S PATTERN 1 1 455 see below (2361 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 | ------------------------------------------------------------------------------------------------------------------------------------ CHIPS1911+4455 1 ACS/WFC ACCUM WFC1 F550M 1 none none none 1 787.0 S CHIPS1911+4455 1 ACS/WFC ACCUM WFC1 F550M 2 none none none 1 787.0 S CHIPS1911+4455 1 ACS/WFC ACCUM WFC1 F550M 3 none none none 1 787.0 S 16038( 4) - 07-Nov-2019 14:33:34 - [ 5] Visit: 02 (Red_cont) 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 CHIPS1911+4 WFC3/IR MULTIAC IR-FIX F110W NSAMP=14, SAMP-SEQ=SPARS50 1 DEF PATTERN 2 1 455 CUM (2611.753 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 | ------------------------------------------------------------------------------------------------------------------------------------ CHIPS1911+4455 1 WFC3/IR MULTIAC IR-FIX F110W 1 1 none none 1 N/A CUM CHIPS1911+4455 1 WFC3/IR MULTIAC IR-FIX F110W 1 2 none none 1 N/A CUM CHIPS1911+4455 1 WFC3/IR MULTIAC IR-FIX F110W 2 1 none none 1 N/A CUM CHIPS1911+4455 1 WFC3/IR MULTIAC IR-FIX F110W 2 2 none none 1 N/A CUM 16038( 4) - 07-Nov-2019 14:33:34 - [ 6] Summary Form for Proposal 16038 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR-FIX, WFC1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/IR ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=14, SAMP-SEQ=SPARS50 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 1, PATTERN 2 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F110W, F550M ------------------------------------------------------------------------------------------------------------------------------------ Target Names CHIPS1911+4455 ------------------------------------------------------------------------------------------------------------------------------------