Science Keywords: Select from 2 to 5 items. Science Keywords is a required field. Small GO Proposals are not allowed in Cycle 26 unless they are Joint Programs. Please specify your scheduling constraints or 'No Constraints' on all Observation forms. Please specify your scheduling constraints or 'No Constraints' on all Observation forms. 0 Assigned ID: 611 ----- Attempting Submission 1 (Tue Nov 27 14:51:26 GMT 2018) ----- Joint NRAO/HST Phase 2 version 1. Schedule for Spitzer and Chandra has not yet been finalized by those observatories. Will need to update HST visit timing requirments once the exact dates are released. 1478917042 ----- Attempting Submission 1 (Wed Jan 09 12:51:28 GMT 2019) ----- VLA & HST Monitoring of Sgr A* in July 2019 with Spitzer and Chandra We propose to use the VLA and WFC3/HST as part of an observing campaign led by Spitzer and Chandra for continuous monitoring of Sgr A* in July 2019. The Chandra (2x24h) and Spitzer (2x24h) have already been approved. The Spitzer mission is scheduled to end in November 2019, the last chance for Spitzer monitoring, which is unique in terms of its continuous coverage in the mid-IR. It is well established that an expanding synchrotron source model can explain flare emission from Sgr A* at radio wavelengths. However, it is not clear if radio, submm and IR flare emission are related to each other. If there is a relationship between low and high frequency emission, our measurements will test a predication in which a time delay between radio and IR tells us about the importance of opacity in the adiabatic expansion of plasma ejected from Sgr A*. In addition, they provide insight into particle acceleration of relativistic particles by determining the synchrotron cooling time scale at mid and near-IR by using Spitzer and HST. In particular, the adiabatic expansion model can explain the simultaneity of peak flare emission at mid-IR and submm in terms of of optical depth effects. The 8 orbits of this proposal need to be scheduled in coordination with the Spitzer, Chandra, and VLA observations of Sgr A* that will be taking place between 12 July 2019 and 4 August 2019. We intend to split the 8 HST orbits allocated to this program into 2 visits of 4 back-to-back orbits each, to obtain monitoring of Sgr A* over a time period of ~6 hours during each of those 2 visits. The 2 visits will be scheduled to overlap as much as possible with the simultaneous observations by the other observatories. We will obtain WFC3/IR observations with the F153M filter and the SPARS-25 readout sequence. This readout sequence not only gives us equally-spaced readout intervals of 25 secs to keep the detector stable, but also results in exposures of 5-6 min duration, which is long enough to perform WFC3 buffer dumps in parallel with the exposures, thus maximizing our on-source time. We will embed the exposures within 4-point dither pattern, in order to mitigate the effects of bad pixels, flat-field uncertainties, and persistence from bright stars. A total of 8 such exposures can be obtained within each orbit, giving us nearly constant coverage of Sgr A* over a span of about 50 mins per orbit. As of 9 Jan 2019, the exact dates and times of the coordinated Spitzer and Chandra observations have not yet been determined. They will be determined from the following list of candidate orbital periods: Orbit Begin UT End UT 2753 12 JUL 10:01 14 JUL 05:29 2754 15 JUL 01:29 16 JUL 20:57 2755 17 JUL 16:57 19 JUL 12:24 2756 20 JUL 08:24 22 JUL 03:52 2757 22 JUL 23:52 24 JUL 19:20 2758 25 JUL 15:20 27 JUL 10:48 2759 28 JUL 06:48 30 JUL 02:16 2760 30 JUL 22:16 01 AUG 17:45 2761 02 AUG 13:45 04 AUG 09:14 A preliminary schedule should be available in March 2019 and a final schedule perhaps in late May 2019. Once those dates are released, we will pick two of them on which to schedule the HST visits. For now, we have simply set the BETWEEN times for the HST visits to be within the above range of 12 JUL 2019 through 04 AUG 2019. Massive Black Holes And Their Host Galaxies 6 false false false false false false false SUPPORTED STELLAR CLUSTER ACCRETION DISK This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 0.15 mJy in H-band WFC3/IR Imaging No No F153M WFC3/IR Imaging No No F153M POS-TARG DITHER 0.572 LINE 0.365 false false 74.653 4 18.528 WFC3-IR-DITHER-BOX-MIN 1 false POS-TARG DITHER 0.572 LINE false false 2 18.528 WFC3-IR-DITHER-LINE 2 false The scheduling data was generated by CASM 26.2.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 15667 :visit-id "01" :proposal-version -1 :trans-version "20181130" :date "09-Jan-2019 07:47:25.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 8147504 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15667 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15667 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2712 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3165 :pcs-gap 0 ) (Tic-Orbit :proposal-id 15667 :visit-id "01" :orbit-number 2 :pcs-time 302 :si-vis-utilization 2712 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3165 :pcs-gap 0 ) (Tic-Orbit :proposal-id 15667 :visit-id "01" :orbit-number 3 :pcs-time 302 :si-vis-utilization 2712 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3165 :pcs-gap 0 ) (Tic-Orbit :proposal-id 15667 :visit-id "01" :orbit-number 4 :pcs-time 302 :si-vis-utilization 2712 :al-overhead-at-end 0 :internal-dur-at-end 576 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3165 :pcs-gap 0 ) false 4 0 The scheduling data was generated by CASM 26.2.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 15667 :visit-id "02" :proposal-version -1 :trans-version "20190514" :date "03-Jul-2019 13:32:11.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 2263184 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15667 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15667 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 1516 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3165 :pcs-gap 0 ) (Tic-Orbit :proposal-id 15667 :visit-id "02" :orbit-number 2 :pcs-time 302 :si-vis-utilization 1516 :al-overhead-at-end 0 :internal-dur-at-end 576 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3165 :pcs-gap 0 ) true 2 0