17579( 5) - 09-Nov-2023 13:14:34 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17579 Version: 5 Check-in Time: 09-Nov-2023 13:14:34 STScI Edit Number: 2 Title A Newly Identified Merging Cluster Near Pericenter ------------------------------------------------------------------------------------ Type Cycle GO 31 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. John P. Hughes Rutgers the State University of New Jersey Y CoI: Mr. Peter Doze Rutgers the State University of New Jersey N CoI: Matt Hilton University of KwaZulu-Natal N CoI: Prof. Nicholas Battaglia Cornell University N CoI: Dr. Cristobal Sifon Pontificia Universidad Catolica de N Valparaiso CoI: Prof. Charles R. Keeton Rutgers the State University of New Jersey N CoI: Dr. Kenda Knowles University of KwaZulu-Natal N CoI: Dr. Kavilan Moodley University of KwaZulu-Natal N ------------------------------------------------------------------------------------ Abstract We have identified a massive cluster ACT-CL J0034.3+0225 at a redshift of 0.388 in the midst of a major merger and close to pericenter crossing based on an archival Chandra observation from Cycle 18. This proposal requests time for a much deeper Chandra observation to better define the cluster's morphology, to measure temperature differences within the core, and to search for shocks and cold fronts. This proposal also requests 5 HST orbits with the ACS/WFC for a gravitational lensing analysis to determine the distribution of total cluster mass for comparison to the gas and galaxies with the goal of setting constraints on the interaction properties of the dark matter, determining the properties of the merger, and studying the shocks and cold fronts in this cluster ------------------------------------------------------------------------------------ Observations Description ------------------------ Our award of 5 HST orbits will use the ACS/WFC to image the full cluster extent out to 1 Mpc (roughly R500) in the F606W filter using a 2x2 mosaic. This will utilize 4 orbits which have an ORIENT constraint to "|avoid contaminating the central region of the cluster by diffraction spikes from the bright star toward the northwest."| The remaining orbit will be used to image the cluster core in the F775W filter also with an ORIENT constraint to match "the existing F814W image to maximize the overlap of HST imaging in the cluster center." In each orbit we will obtain an image through a single filter using a 4-point dither pattern that provides optimal coverage of the central chip gap area, while allowing for efficient cosmic-ray rejection. Review of the visit planner output indicates that a +/-1 deg tolerance on the ORIENT of the F775W image allows for good visibiity. For the 2x2 mosaic pointing, posiitons were genrated iteratively to ensure there were no gaps in coverage across the full mosaic. An ORIENT of 47.5 deg provided a decent visibiity window. ------------------------------------------------------------------------------------ 17579( 5) - 09-Nov-2023 13:14:34 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 ACT-CL-J0034 CLUSTER OF GALAXIES, RA=00H34M28.1986S, J2000 V = 20 .4+0225-F0 GRAVITATIONAL LENS, DEC=+02D25'31.15" RICH CLUSTER Reference Frame: ICRS Extended: YES Comments: This position was selcted to match the previous F814W image of this cluster. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.0 0.0 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 2 ACT-CL-J0034 CLUSTER OF GALAXIES, RA=00H34M17.1556S, J2000 V = 20 .4+0225-F1 GRAVITATIONAL LENS, DEC=+02D25'26.51" RICH CLUSTER Reference Frame: ICRS Extended: YES Comments: This position was entered by hand for the western field of the mosaic. ------------------------------------------------------------------------------------------------------------------------------------ 3 ACT-CL-J0034 CLUSTER OF GALAXIES, RA=00H34M25.3544S, J2000 V = 20 .4+0225-F2 GRAVITATIONAL LENS, DEC=+02D23'4.04" RICH CLUSTER Reference Frame: ICRS Extended: YES Comments: This position was entered by hand for the southern field of the mosaic. ------------------------------------------------------------------------------------------------------------------------------------ 4 ACT-CL-J0034 CLUSTER OF GALAXIES, RA=00H34M34.5693S, J2000 V = 20 .4+0225-F3 GRAVITATIONAL LENS, DEC=+02D25'22.95" RICH CLUSTER Reference Frame: ICRS Extended: YES Comments: This position was entered by hand for the eastern field of the mosaic. ------------------------------------------------------------------------------------------------------------------------------------ 5 ACT-CL-J0034 CLUSTER OF GALAXIES, RA=00H34M26.5056S, J2000 V = 20 .4+0225-F4 GRAVITATIONAL LENS, DEC=+02D27'46.40" RICH CLUSTER Reference Frame: ICRS Extended: YES Comments: This position was entered by hand for the northern field of the mosaic. ------------------------------------------------------------------------------------------------------------------------------------ 17579( 5) - 09-Nov-2023 13:14:34 - [ 3] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 2.276 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 85.29 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 5.943 Line_Spacing 3.077 Coordinate_Frame POS-TARG Pattern_Orient 91.429 Angle_Between_Sides 166.993 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 17579( 5) - 09-Nov-2023 13:14:34 - [ 4] Visit: 01 (F775W image) Visit Requirements: ORIENT 69.5D TO 71.5 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 ACT-CL-J003 ACS/WFC ACCUM WFC F775W 1 535 S GS ACQ SCENARIO ONEB1B3; 4.4+0225-F0 (2140 S) PATTERN 2 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFC F775W 1 none none none 1 N/A -F0 ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFC F775W 2 none none none 1 N/A -F0 ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFC F775W 3 none none none 1 N/A -F0 ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFC F775W 4 none none none 1 N/A -F0 17579( 5) - 09-Nov-2023 13:14:34 - [ 5] Visit: 02 (F606W F1) Visit Requirements: ORIENT 47.5D TO 47.5 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 ACT-CL-J003 ACS/WFC ACCUM WFCENTER F606W 1 510 S PATTERN 3 1 4.4+0225-F1 (2040 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 | ------------------------------------------------------------------------------------------------------------------------------------ ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 1 none none none 1 N/A -F1 ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 2 none none none 1 N/A -F1 ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 3 none none none 1 N/A -F1 ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 4 none none none 1 N/A -F1 17579( 5) - 09-Nov-2023 13:14:34 - [ 6] Visit: 03 (F606W F2) Visit Requirements: SAME ORIENT AS 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 ACT-CL-J003 ACS/WFC ACCUM WFCENTER F606W 1 510 S PATTERN 3 1 4.4+0225-F2 (2040 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 | ------------------------------------------------------------------------------------------------------------------------------------ ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 1 none none none 1 N/A -F2 ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 2 none none none 1 N/A -F2 ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 3 none none none 1 N/A -F2 ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 4 none none none 1 N/A -F2 17579( 5) - 09-Nov-2023 13:14:34 - [ 7] Visit: 04 (F606W F3) Visit Requirements: SAME ORIENT AS 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 ACT-CL-J003 ACS/WFC ACCUM WFCENTER F606W 1 510 S GS ACQ SCENARIO ONEB1B3; 4.4+0225-F3 (2040 S) PATTERN 3 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 1 none none none 1 N/A -F3 ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 2 none none none 1 N/A -F3 ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 3 none none none 1 N/A -F3 ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 4 none none none 1 N/A -F3 17579( 5) - 09-Nov-2023 13:14:34 - [ 8] Visit: 05 (F606W F4) Visit Requirements: SAME ORIENT AS 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 ACT-CL-J003 ACS/WFC ACCUM WFCENTER F606W 1 510 S PATTERN 3 1 4.4+0225-F4 (2040 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 | ------------------------------------------------------------------------------------------------------------------------------------ ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 1 none none none 1 N/A -F4 ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 2 none none none 1 N/A -F4 ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 3 none none none 1 N/A -F4 ACT-CL-J0034.4+0225 1 ACS/WFC ACCUM WFCENTER F606W 4 none none none 1 N/A -F4 17579( 5) - 09-Nov-2023 13:14:34 - [ 9] Summary Form for Proposal 17579 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC, WFCENTER ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GS ACQ SCENARIO ONEB1B3, ORIENT 47.5D TO 47.5 D, ORIENT 69.5D TO 71.5 D, PATTERN 2 1, PATTERN 3 1, SAME ORIENT AS 02 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F606W, F775W ------------------------------------------------------------------------------------------------------------------------------------ Target Names ACT-CL-J0034.4+0225-F0, ACT-CL-J0034.4+0225-F1, ACT-CL-J0034.4+0225-F2, ACT-CL-J0034.4+0225-F3, ACT-CL-J0034.4+0225-F4 ------------------------------------------------------------------------------------------------------------------------------------