0 Assigned ID: 5793 ----- Attempting Submission 1 (Tue Mar 26 22:59:39 GMT 2024) ----- HST Phase I Proposal 5793 successfully submitted. Receipt: # 5793-1 ----- Attempting Submission 2 (Tue Mar 26 23:58:12 GMT 2024) ----- This is essentially the same program as previous GO proposals # 14159 and # 15191. There were some slight changes in exposure times to accomodate the new reduced efficiency but there should be minimal impact. 1878201350 ----- Attempting Submission 1 (Sun Aug 11 20:25:43 GMT 2024) ----- A superluminal jet in 3C264: the view at 30 3C264 is a nearby radio galaxy with a prominent optical jet. Previous HST observations from the 1990s through the 2010s discovered not only the fastest-ever superluminal speed (on kpc scales) of 7c for a knot in the jet, but also captured the motion of this knot through the start of a collision with slow-moving material downstream, with concomitant brightening indicating in-situ particle acceleration. This remarkable discovery represents the first direct evidence for the "internal shock" model for particle acceleration, a mechanism proposed to explain variability and particle acceleration in sources as diverse as gamma-ray bursts, microquasars, and jetted AGN. The collision is expected to manifest in brightening and hardening of the optical spectrum and increasing polarization over the next several years to decade, and this unprecidented source gives us the unique opportunity to directly evaluate the applicability, efficiency and physical characterization of the internal shock mechanism.Following previous HST/VLA/Chandra observations in 2018/2019 showing a continued rise in flux and polarization in the shock region, we propose a new epoch of imaging to monitor the spectral evolution of the colliding knots and continue spatial proper motion measurements of the jet features, for comparison to the expectations from theoretical models. In keeping with past monitorig we request 2 orbits with WFC3/UVIS (near-UV, B, and I band), 1 orbit with the ACS/WFC polarizers in F606W, as well as K-band VLA and Chandra ACIS observations. Observations are of an optical jet approximately 2" long in the northeast direction, as part of a monitoring proposal for flaring behavior (this is the follow-up of an identical set of observations in 2015/16 and 2018/19). The field of view is dominated by the host galaxy, a nearby elliptical. The observations consist of two visits: the first is WFC3/UVIS imaging in three filters (F475W, F814W splitting the first orbit, F225W in the second orbit). The second visit is ACS/WFC polarimetry in F606W filter. Orient constraints are specified to avoid any risk of the central nucleus from producing diffraction spikes that run over the jet. The team includes several leading experts in the study of resolved optical jets with HST (E. Meyer, W. Sparks, M. Chiaberge, E. perlman) and the team has collectively lead dozens of previous HST programs on jets and other targets. The most directly relevant is the Cycle 21 program (GO-13327), |"Proper Motions at 500 Mpc: Measuring Superluminal Motions in Optical Jets with HST|", which provided the observations which lead to the discovery of the internal shocks in 3C 264 (published in Nature) that we are proposing to further monitor in this program, and the previous monitoring epochs in cycles 23 and 25, which were published in Archer et al., 2020. The team includes experts in polarimetry, including the use of HST polarizers (W. Sparks, E. Perlman, E. Meyer) who have published several dozen refereed papers on large-scale relativistic jets. The team includes experts on HST astrometry and proper motions (J. Anderson, R. van der Marel, E. Meyer) as well as an expert in imaging deconvolution with Chandra (K. Reddy) and experts in radio-wavelength studies of jets (E. Meyer, E. perlman, O. Shuvo, K. Reddy). Supermassive Black Holes and Active Galaxies 6 false false false false false false false true PRIMARY 90 1 true SUPPORTED GALAXY ELLIPTICAL JET NUCLEUS RADIO GALAXY This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 The scheduling data was generated by CASM 32.0. CASM was run in Phase I mode. WFC3/UVIS Imaging No No F225W WFC3/UVIS Imaging No No F475W WFC3/UVIS Imaging No No F814W The scheduling data was generated by CASM 32.0. CASM was run in Phase I mode. ACS/WFC Imaging No Yes F606W POS-TARG DITHER 0.135 LINE false false 3 46.84 WFC3-UVIS-DITHER-LINE-3PT 1 false POS-TARG DITHER 0.173 LINE 0.112 false false 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 2 false POS-TARG DITHER 3.011 LINE false false 2 85.28 ACS-WFC-DITHER-LINE 3 false POS-TARG DITHER 0.145 LINE false false 2 46.84 WFC3-UVIS-DITHER-LINE 4 false The scheduling data was generated by CASM 32.1.1. CASM was run in Phase II mode. /Users/meyer/Dropbox/Research/proposals/2024_proposals/HST_3c264/OP-cache/hst_3c264_17781_phase2-v01.xml 1 orbit of ACS polarization in F606W filter. The observations cover the three polarization angle filters, with two exposures each, using a 2-point dither pattern to improve image quality and mitigate cosmic ray artifacts. Orient constraints are specified to avoid any risk of the central nucleus from producing diffraction spikes that run over the jet. (Tic-Visit :proposal-id 17781 :visit-id "01" :proposal-version -1 :trans-version "20240604" :date "11-Aug-2024 15:09:30.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 426464 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17781 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17781 :visit-id "01" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2635 :al-overhead-at-end 0 :internal-dur-at-end 269 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3023 :pcs-gap 0 ) true 1 0 /Users/meyer/Dropbox/Research/proposals/2024_proposals/HST_3c264/OP-cache/hst_3c264_17781_phase2-v02.xml The scheduling data was generated by CASM 32.1.1. CASM was run in Phase II mode. We used a 3-point dithering pattern for the sets of F475W (3 exp) and F814W (2 exp) observations in the first orbit, with an additional shorter exposure in the latter filter to fill the orbit (the third exposure is particularly useful to minimize impacts of CR). We used a 4-point dithering pattern for the 4 F225W exposures in the second orbit. Orient constraints are specified to avoid any risk of the central nucleus from producing diffraction spikes that run over the jet. POS TARGS are also used to put the target somewhat closer to the readout corner to minimize CTE. (Tic-Visit :proposal-id 17781 :visit-id "02" :proposal-version -1 :trans-version "20240604" :date "11-Aug-2024 15:09:41.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 2887488 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17781 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17781 :visit-id "02" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2641 :al-overhead-at-end 128 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3023 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17781 :visit-id "02" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2622 :al-overhead-at-end 126 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3023 :pcs-gap 0 ) true 2 0