17925( 2) - 30-Jan-2025 15:21:38 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17925 Version: 2 Check-in Time: 30-Jan-2025 15:21:38 STScI Edit Number: 0 Title 20 Years of time baseline, The 3D kinematics of Centaurus A ------------------------------------------------------------------------------------ Type Cycle GO 32 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Paul Bennet Space Telescope Science Institute Y CoI: Dr. Sangmo Tony Sohn Space Telescope Science Institute N CoI: Dr. Roeland P. van der Marel Space Telescope Science Institute N CoI: Dr. Kevin Andrew McKinnon Canadian Institute for Theoretical N Astrophysics CoI: Dr. Ekta Patel University of Utah N CoI: Dr. Mark Fardal Eureka Scientific Inc. N CoI: Dr. Nitya Kallivayalil The University of Virginia N CoI: Dr. Laura L. Watkins Space Telescope Science Institute - ESA - N JWST CoI: Jack Thomas Warfield The University of Virginia N CoI: Dr. Marcel Pawlowski Leibniz-Institut für Astrophysik Potsdam N (AIP) ------------------------------------------------------------------------------------ Abstract Centaurus A (Cen A, NGC 5128) is the nearest elliptical galaxy to the Milky Way (MW), the most massive galaxy in the Local Volume and the nearest galaxy to host an active galactic nucleus (AGN). Cen A's importance to astronomy is exemplified by it being one of the 20 most cited objects in the SIMBAD database. We propose to use ACS/WFC to measure the proper motion (PM) of Cen A and use this information to: (1) for the first time, measure the transverse velocity of a galaxy group relative to the Local Group (LG), allowing us totest cosmological expectations and simulations in a new way and on far larger scales, and, (2) begin the process of determining the long-term stability of the reported plane of satellites in the Cen A group. It is vital that the second epoch of observations needed to derive Cen~A's PM is taken before ACS/WFC is decommissioned. Second-epoch observations with any other instrument would produce PMs with significant systematics, and new observations would need over 20 years to achieve the precision possible now with ACS/WFC. ------------------------------------------------------------------------------------ Observations Description ------------------------ We will observe a halo field for Cen A with 12 single orbit exposures. This will allow us to get a second epoch of observations for finding the proper motion of Cen A and its galaxy group. ------------------------------------------------------------------------------------ 17925( 2) - 30-Jan-2025 15:21:38 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 CENA-HALO GALAXY, ELLIPTICAL, RA=13H25M15.1000S, J2000 V = 24 HALO DEC=-43D34'30.00" Reference Frame: ICRS Extended: YES Comments: This is the magnitude of a TRGB star, at this distance Cen A is resolved into indivdual stars and we are well into the halo so the magnitude of Cen A itself is irrelevent to these observations. ------------------------------------------------------------------------------------------------------------------------------------ 17925( 2) - 30-Jan-2025 15:21:38 - [ 3] Visit: 01 Visit Requirements: ORIENT 308D TO 248 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 CENA-HALO ACS/WFC ACCUM WFC F814W 1 2449 S POS TARG 0, 0 (2449 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 CENA-HALO ACS/WFC ACCUM WFC F814W 1 2449 S POS TARG 0.1740, 0.1850 see below (2511 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 | ------------------------------------------------------------------------------------------------------------------------------------ CENA-HALO 1 ACS/WFC ACCUM WFC F814W none none none none 1 N/A CENA-HALO 2 ACS/WFC ACCUM WFC F814W none none none none 2 2511.0 S 17925( 2) - 30-Jan-2025 15:21:38 - [ 4] Visit: 02 Visit Requirements: SAME ORIENT AS 01; GROUP 02, 01, 03, 04, 05, 06 WITHIN 30D 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 CENA-HALO ACS/WFC ACCUM WFC F814W 1 2449 S POS TARG 0.3232, 0.1235 (2449 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 CENA-HALO ACS/WFC ACCUM WFC F814W 1 2449 S POS TARG 0.1005, 0.3305 see below (2511 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 | ------------------------------------------------------------------------------------------------------------------------------------ CENA-HALO 1 ACS/WFC ACCUM WFC F814W none none none none 1 N/A CENA-HALO 2 ACS/WFC ACCUM WFC F814W none none none none 2 2511.0 S 17925( 2) - 30-Jan-2025 15:21:38 - [ 5] Visit: 03 Visit Requirements: SAME ORIENT AS 01; GROUP 03, 01, 02, 04, 05, 06 WITHIN 30D 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 CENA-HALO ACS/WFC ACCUM WFC F814W 1 2449 S POS TARG 0.5030, 0.0460 (2449 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 CENA-HALO ACS/WFC ACCUM WFC F814W 1 2449 S POS TARG 0.6670, 0.2310 see below (2511 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 | ------------------------------------------------------------------------------------------------------------------------------------ CENA-HALO 1 ACS/WFC ACCUM WFC F814W none none none none 1 N/A CENA-HALO 2 ACS/WFC ACCUM WFC F814W none none none none 2 2511.0 S 17925( 2) - 30-Jan-2025 15:21:38 - [ 6] Visit: 04 Visit Requirements: SAME ORIENT AS 01; GROUP 04, 01, 02, 03, 05, 06 WITHIN 30D 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 CENA-HALO ACS/WFC ACCUM WFC F814W 1 2449 S POS TARG 0.8262, 0.1695 (2449 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 CENA-HALO ACS/WFC ACCUM WFC F814W 1 2449 S POS TARG 0.6035, 0.3765 see below (2511 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 | ------------------------------------------------------------------------------------------------------------------------------------ CENA-HALO 1 ACS/WFC ACCUM WFC F814W none none none none 1 N/A CENA-HALO 2 ACS/WFC ACCUM WFC F814W none none none none 2 2511.0 S 17925( 2) - 30-Jan-2025 15:21:38 - [ 7] Visit: 05 Visit Requirements: SAME ORIENT AS 01; GROUP 05, 01, 02, 03, 04, 06 WITHIN 30D 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 CENA-HALO ACS/WFC ACCUM WFC F814W 1 2449 S POS TARG 0.1180, 0.5180 (2449 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 CENA-HALO ACS/WFC ACCUM WFC F814W 1 2449 S POS TARG 0.2920, 0.7030 see below (2511 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 | ------------------------------------------------------------------------------------------------------------------------------------ CENA-HALO 1 ACS/WFC ACCUM WFC F814W none none none none 1 N/A CENA-HALO 2 ACS/WFC ACCUM WFC F814W none none none none 2 2511.0 S 17925( 2) - 30-Jan-2025 15:21:38 - [ 8] Visit: 06 Visit Requirements: SAME ORIENT AS 01; GROUP 06, 01, 02, 03, 04, 05 WITHIN 30D 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 CENA-HALO ACS/WFC ACCUM WFC F814W 1 2449 S POS TARG 0.4412, 0.6415 (2449 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 CENA-HALO ACS/WFC ACCUM WFC F814W 1 2449 S POS TARG 0.2185, 0.8485 see below (2511 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 | ------------------------------------------------------------------------------------------------------------------------------------ CENA-HALO 1 ACS/WFC ACCUM WFC F814W none none none none 1 N/A CENA-HALO 2 ACS/WFC ACCUM WFC F814W none none none none 2 2511.0 S 17925( 2) - 30-Jan-2025 15:21:38 - [ 9] Summary Form for Proposal 17925 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GROUP 02, 01, 03, 04, 05, 06 WITHIN 30D, GROUP 03, 01, 02, 04, 05, 06 WITHIN 30D, GROUP 04, 01, 02, 03, 05, 06 WITHIN 30D, GROUP 05, 01, 02, 03, 04, 06 WITHIN 30D, GROUP 06, 01, 02, 03, 04, 05 WITHIN 30D, ORIENT 308D TO 248 D, POS TARG 0, 0, POS TARG 0.1005, 0.3305, POS TARG 0.1180, 0.5180, POS TARG 0.1740, 0.1850, POS TARG 0.2185, 0.8485, POS TARG 0.2920, 0.7030, POS TARG 0.3232, 0.1235, POS TARG 0.4412, 0.6415, POS TARG 0.5030, 0.0460, POS TARG 0.6035, 0.3765, POS TARG 0.6670, 0.2310, POS TARG 0.8262, 0.1695, SAME ORIENT AS 01 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names CENA-HALO ------------------------------------------------------------------------------------------------------------------------------------