This program is designed to be coordinated with the spring 2026 EHT/Chandra/NuSTAR movie campaign on M87. Simultaneous observations are not required, but the available windows during this time period are fairly narrow. 1445363594 Assigned ID: 6917 ----- Attempting Submission 1 (Thu Aug 28 15:10:41 GMT 2025) ----- HST Phase I Proposal 6917 successfully submitted. Receipt: # 6917-1 FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser I am using FLASH values advised by my CS, so I believe these are acceptable regardless of the warnings. -893785007 ----- Attempting Submission 1 (Wed Oct 01 14:06:21 GMT 2025) ----- I am using FLASH values advised by my CS, so I believe these are acceptable. A Movie Campaign on M87: Chandra, NuSTAR, Hubble, and the EHT With a large, well-studied jet and the second largest event horizon on the sky, the radio galaxy M87 is one of the primary targets for the Event Horizon Telescope, but the origin of its jet remains unclear. If the jet is powered by the supermassive black hole spin, there should be a direct connection between the bright shadow/ring and the subsequent evolution of the jet. An upcoming EHT movie campaign will test this connection in 2026 (priv comm) with an unprecedented study of the dynamics of the turbulent near-horizon plasma. Chandra observations (4x5 ks) coordinated with NuSTAR (priv comm) and HST (4 orbits) will be essential for tracking the high-energy variability of this plasma, diagnosing particle heating and acceleration, and interpreting models of the accretion flow. The goal of our HST program is to study the optical and UV variability of M87 in conjunction with Chandra/EHT observations in Spring 2026. We are particularly interested in tracking the relative flux and SED changes of the core and the knot HST-1 over time. Our observations will occur in two vists pieces consisting of two orbits each. This is now standard for M87. Beyond taking place during the EHT campaign, no specific coordination is required. We adopt a modified version of the WFC3/UVIS observing strategy used for historical Hubble M87 monitoring (e.g. PI:Shara). In our analysis, comparable exposures produced to 3-10% uncertainties on the core and HST-1 fluxes after subtracting the host galaxy contribution. Generally each visit consists of two orbits to acquire observations in F275W and F814W (orbit 1) and F390W and F606W (orbit 2) in ACCUM mode. The first orbit consists of three dithered 449 s exposures in F275W and two dithered 348 s exposures in F814W in ACCUM mode, for a total of 2043 s on source; the second orbit has 2x489 s in F390W and 3x348 s in F606W. ETC calculations are given for the nucleus and are approximate as they neglect the host galaxy. The remaining ~1 ks per orbit is covered by overhead (setup, readouts, filter changes, and dithering). We mitigate CTE with a flash to increase the background; sub-exposures reduce cosmic rays. The second visit has a ~3-day window. Most members of the team are active members of the Event Horizon Telescope Collaboration or partners in its Multiwavelength Working Group. Dr. Balokovic is an expert in X-ray observations of accreting supermassive black holes. Prof. Bower is the Project Scientist for the EHT and is an expert in radio/submm variability of accreting black holes. Prof. Chandra is an expert in accretion and blazars. Dr. Doeleman is the Founding Director of the EHT. Dr. Emami-Meibody is an expert in polarization and radiative transfer in General Relativity. Prof. Falcone is an expert in Swift observation coordination, data analysis, and X-ray emission from jets. Prof. Haggard is an expert in X-ray variability and spectroscopy of supermassive black holes. Dr. Jorstad is an expert in multiwavelength variability of blazars. Prof. Kaur is an expert in Swift UV/X-ray imaging and spectroscopy of M87. Dr. Krichbaum is an expert in radio astronomy and mm VLBI. Prof. Markoff is an expert in the physics of jets and accretion. Prof. Moscibrodzka is an expert in radiative transfer and GRMHD simulations of accretion flows. Neilsen is an expert in X-ray spectral variability of accreting black holes. Prof. Nowak is an expert in X-ray spectral variability of accreting black holes. Dr. Principe is an expert in high-energy observations of supermassive black holes. Dr. Ramakrishnan is an expert in multifrequency variability and broadband SED modeling of AGN. Dr. Ripperda is an expert in GRMHD simulations of reconnection processes. Mr. Sheridan is a student with three years of experience studying the X-ray emission from M87. Prof. Zhang is an expert in X-ray observations of galactic nuclei. Supermassive Black Holes and Active Galaxies 6 false false false false false false true SECONDARY CHANDRA 27700157 false SUPPORTED GALAXY JET RADIO GALAXY This object was generated by the targetselector and retrieved from the SIMBAD database. SIMBAD listed proper motion for this target. When retrieving targets with PM from SIMBAD, APT requests the coordinates be calculated with an epoch of the year 2000. Do not modify this epoch. Always review coordinates using the Target Confirmation tool, which graphically displays the PM. J2000 J2000 WFC3/UVIS Imaging No No F275W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F390W WFC3/UVIS Imaging No No F606W POS-TARG DITHER DITHER 4 2.414 WFC3-UVIS-DITHER-BOX false 81.785 true 0.112 0.173 3 85.759 POS-TARG WFC3-UVIS-GAP-LINE 23.884 1 false POS-TARG DITHER 0.145 LINE false false 2 46.84 WFC3-UVIS-DITHER-LINE 2 false /Users/jneilsen/Documents/Villanova/Proposals/HST/Cycle33/OP-cache/Movie_PhaseII-v01.xml The scheduling data was generated by CASM 33.1. CASM was run in Phase II mode. This visit is scheduled earlier in the EHT campaign. No specific coordination with the EHT, Chandra, or NuSTAR is required. (Tic-Visit :proposal-id 18187 :visit-id "01" :proposal-version -1 :trans-version "20250624" :date "01-Oct-2025 08:35:44.0" :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 2887504 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18187 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18187 :visit-id "01" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2594 :al-overhead-at-end 119 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2974 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18187 :visit-id "01" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2594 :al-overhead-at-end 119 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2974 :pcs-gap 0 ) true 2 0 /Users/jneilsen/Documents/Villanova/Proposals/HST/Cycle33/OP-cache/Movie_PhaseII-v02.xml The scheduling data was generated by CASM 33.1. CASM was run in Phase II mode. This visit is scheduled later in the EHT campaign. No specific coordination with the EHT, Chandra, or NuSTAR is required. (Tic-Visit :proposal-id 18187 :visit-id "02" :proposal-version -1 :trans-version "20250624" :date "01-Oct-2025 08:37:02.0" :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 2887504 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18187 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18187 :visit-id "02" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2594 :al-overhead-at-end 119 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2974 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18187 :visit-id "02" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2594 :al-overhead-at-end 119 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2974 :pcs-gap 0 ) true 2 0