17816( 3) - 21-Jan-2026 19:12:38 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17816 Version: 3 Check-in Time: 21-Jan-2026 19:12:38 STScI Edit Number: 1 Title The largest BAL acceleration: testing disk wind models ------------------------------------------------------------------------------------ Type Cycle GO 32 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Nahum Arav Virginia Polytechnic Institute and State Y University CoI: Dr. Xinfeng Xu Northwestern University N CoI: Dr. Gerard A. Kriss Space Telescope Science Institute N CoI: Prof. Kirk T. Korista Western Michigan University N CoI: Dr. Maryam Dehghanian University of Kentucky N CoI: Mr. Mayank Sharma Virginia Polytechnic Institute and State Y University CoI: Dr. Doyee Byun University of Michigan N ------------------------------------------------------------------------------------ Abstract Quasar outflows are invoked as the major agent of AGN feedback and are crucial for the mass inflow/outflow balance in the vicinity of super massive black holes. Significant effort was invested over the past 3 decades in creating theoretical models for the formation and acceleration of these outflows. However, there is no decisive empirical test that confirms or refutes such models. These models have specific predictions for an outflow found in its acceleration phase. Recently, an outflow with the largest acceleration ever detected was found, and it is the ideal candidate to test acceleration models. Previous HST observations in 2011 and 2017 showed that the outflow's velocity shifted by -1550 km/s (the largest shift observed to date). Any one episode of acceleration can be accommodated by a disk-wind model solution. However, that solution predicts specific acceleration and distance values for future times and thus can be tested. We propose a 3rd epoch of observations, which will yield both the velocity and distance from the central source for the outflow. Thus, we will obtain a full empirical test for the acceleration models, and more generally, an unprecedented observational study of a broad absorption line outflow acceleration. ------------------------------------------------------------------------------------ Observations Description ------------------------ To accurately determine the outflow distance to the central source (R), a minimal spectral resolution of 5000 is needed as well as high throughput. Therefore, the use of COS G130M and G160M is necessary. The photoionization solution (PIS) derived from the 2017 epoch and the corresponding electron number denity (n_e) (and therefore R) are loosely constrained. The PIS can be better constrained if we can measure the ionic column densities (N_ion) for both O IV and Na IX, as compared with the current upper limits. Our simulations for a range of S/N show that to obtain a meaningful constraint on the M95 acceleration model, a S/N of 30 per a R = 5000 17816( 3) - 21-Jan-2026 19:12:38 - [ 2] resolution element is required. Using the COS ETC, we determine that the desired S/N can be obtained in 7 ks and 13 ks for the G130M and G160M gratings, respectively. Taking into account the overheads, this translates to a total of 11 orbits. In selecting our grating settings, we have chosen central wavelengths to avoid placing the gap between the COS detectors on any of the crucial spectral features we will use in our analysis. For ETC calculations we use the FOS-based QSO composite spectrum at the redshift of the object with a foreground E(B-V) as given by NED. Since the object has been observed safely with COS before, there are no bright object concerns for our observations. To plan our observations, we use ETC calculations that are conservative (both fainter and brighter) to ensure success. W e plan target acquisition exposure times for minimum flux that is 3x lower than the observed flux, and set BUFFER-TIME for flux 3x brighter, and use the factor of 2/3 recommended by the ETC. In practice, all BUFFER times from the ETC are >4000 secs, so, to optimize buffer useage and minimize overheads, we generally choose BUFFER-TIME such that BUFFER-TIME=ExposureTime - 110 s. ------------------------------------------------------------------------------------ 17816( 3) - 21-Jan-2026 19:12:38 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 2MASS-J10424 GALAXY, NUCLEUS, QSO, RA=10H42M44.2385S +/- 0.1", J2000 Z = V = 16.75 +/- 0.5 1.3e-15 at 1516 A 423+1646560 WIND DEC=+16D46'56.09" +/- 0.1" 0.978063 Reference Frame: ICRS Extended: NO Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. 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 ------------------------------------------------------------------------------------------------------------------------------------ 17816( 3) - 21-Jan-2026 19:12:38 - [ 4] Visit: 01 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 2MASS-J1042 COS/NUV ACQ/IMA PSA MIRRORB 1 385 S (385 4423+164656 GE S) 0 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASS-J1042 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=600, FP-POS=ALL 1 710 S 4423+164656 G see below 0 (2884 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 2MASS-J1042 COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=520, FP-POS=ALL 1 630 S 4423+164656 G see below 0 (2525 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 | ------------------------------------------------------------------------------------------------------------------------------------ 2MASS-J10424423+164 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A 6560 GE 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 1 1 715.0 S 6560 G 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 2 1 715.0 S 6560 G 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 3 2 727.0 S 6560 G 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 4 2 727.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1577 none none none 1 2 647.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1577 none none none 2 3 626.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1577 none none none 3 3 626.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1577 none none none 4 3 626.0 S 6560 G 17816( 3) - 21-Jan-2026 19:12:38 - [ 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 2MASS-J1042 COS/NUV ACQ/IMA PSA MIRRORB 1 385 S (385 4423+164656 GE S) 0 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASS-J1042 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=600, FP-POS=ALL 1 710 S 4423+164656 G see below 0 (2892 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 2MASS-J1042 COS/FUV TIME-TA PSA G160M 1533 BUFFER-TIME=520, FP-POS=ALL 1 630 S 4423+164656 G see below 0 (2529 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 | ------------------------------------------------------------------------------------------------------------------------------------ 2MASS-J10424423+164 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A 6560 GE 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 1 1 715.0 S 6560 G 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 2 1 715.0 S 6560 G 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 3 2 731.0 S 6560 G 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 4 2 731.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1533 none none none 1 2 651.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1533 none none none 2 3 626.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1533 none none none 3 3 626.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1533 none none none 4 3 626.0 S 6560 G 17816( 3) - 21-Jan-2026 19:12:38 - [ 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 2MASS-J1042 COS/NUV ACQ/IMA PSA MIRRORB 1 385 S (385 4423+164656 GE S) 0 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASS-J1042 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=155, FP-POS=ALL 1 265 S 4423+164656 G see below 0 (1056 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 2MASS-J1042 COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=1000, FP-POS=ALL 1 1110 S 4423+164656 G see below 0 (4440 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 | ------------------------------------------------------------------------------------------------------------------------------------ 2MASS-J10424423+164 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A 6560 GE 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 1 1 264.0 S 6560 G 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 2 1 264.0 S 6560 G 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 3 1 264.0 S 6560 G 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 4 1 264.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1577 none none none 1 2 1105.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1577 none none none 2 2 1105.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1577 none none none 3 3 1115.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1577 none none none 4 3 1115.0 S 6560 G 17816( 3) - 21-Jan-2026 19:12:38 - [ 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 2MASS-J1042 COS/NUV ACQ/IMA PSA MIRRORB 1 385 S (385 4423+164656 GE S) 0 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASS-J1042 COS/FUV TIME-TA PSA G160M 1533 BUFFER-TIME=690, FP-POS=ALL 1 800 S 4423+164656 G see below 0 (3151 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 | ------------------------------------------------------------------------------------------------------------------------------------ 2MASS-J10424423+164 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A 6560 GE 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G160M 1533 none none none 1 1 1387.0 S 6560 G 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G160M 1533 none none none 2 2 588.0 S 6560 G 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G160M 1533 none none none 3 2 588.0 S 6560 G 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G160M 1533 none none none 4 2 588.0 S 6560 G 17816( 3) - 21-Jan-2026 19:12:38 - [ 8] Visit: 05 (Visit 03 repeat) 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 2MASS-J1042 COS/NUV ACQ/IMA PSA MIRRORB 1 385 S (385 4423+164656 GE S) 0 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASS-J1042 COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=155, FP-POS=ALL 1 265 S 4423+164656 G see below 0 (1056 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 2MASS-J1042 COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=1000, FP-POS=ALL 1 1110 S 4423+164656 G see below 0 (4440 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 | ------------------------------------------------------------------------------------------------------------------------------------ 2MASS-J10424423+164 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A 6560 GE 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 1 1 264.0 S 6560 G 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 2 1 264.0 S 6560 G 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 3 1 264.0 S 6560 G 2MASS-J10424423+164 2 COS/FUV TIME-TA PSA G130M 1222 none none none 4 1 264.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1577 none none none 1 2 1105.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1577 none none none 2 2 1105.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1577 none none none 3 3 1115.0 S 6560 G 2MASS-J10424423+164 3 COS/FUV TIME-TA PSA G160M 1577 none none none 4 3 1115.0 S 6560 G 17816( 3) - 21-Jan-2026 19:12:38 - [ 9] Summary Form for Proposal 17816 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1000, BUFFER-TIME=155, BUFFER-TIME=520, BUFFER-TIME=600, BUFFER-TIME=690, FP-POS=ALL ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, G160M, MIRRORB ------------------------------------------------------------------------------------------------------------------------------------ Target Names 2MASS-J10424423+1646560 ------------------------------------------------------------------------------------------------------------------------------------