0 Assigned ID: 32 ----- Attempting Submission 1 (Wed Aug 01 20:07:04 GMT 2018) ----- We emphasize that the orbits be taken back-to-back, so that the NUV and FUV observations are as close in time as possible. The flux value of the target, ~4.7e-14 erg/s/cm^2/A at rest-frame 1450A (or observed frame 1474A), was determined by taking the NUV fluxes we measure with Swfit/UVOT, of mag~14.7, then scaling a Vanden-Berk-like quasar composite spectrum (redshifted) to match that. These comments till apply to this resubmission (Aug 17). -1291031137 ----- Attempting Submission 1 (Tue Aug 14 01:32:35 GMT 2018) ----- HST Phase II Proposal 15604 (phaseII.apt) successfully submitted. Receipt: # 15604-1 ----- Attempting Submission 2 (Thu Aug 16 01:09:54 GMT 2018) ----- HST Phase II Proposal 15604 (phaseII.apt) successfully submitted. Receipt: # 15604-2 ----- Attempting Submission 3 (Fri Aug 17 05:23:56 GMT 2018) ----- We are currently observing an AGN caught in the act of changing its accretion state. The AGN 1ES 1927+654, formerly a "true" Type-2, has recently experienced a strong and sudden brightening accompanied by the emergence of broad Balmer lines in the optical spectrum. Observing these changes in real time offers a great opportunity to address open questions in AGN accretion. Our optical spectroscopic sequence shows, for the first time, a time-resolved increase of the blue continuum flux preceding the formation of the broad lines, allowing us to constrain the size of the broad-line region. HST UV spectra taken now will reveal the presence of outflows suggested to be associated with such a transition, and will test competing models proposed to explain the perplexing rapid time scales associated with changing look AGN. 1ES 1927+654 is rapidly fading back to its quiescent state, making the proposed observations a unique but highly time critical opportunity. We propose for one orbit of DD time to follow-up with NUV/FUV spectroscopy a recent optical transient in the nucleus of the AGN 1ES 1927+654. In the FUV, COS is preferred to STIS for its higher throughout. We request both FUV and NUV to cover the emission lines CIV 1549, HeII 1640, OIII] 1664, NIII] 1750, CIII] 1909, and MgII 2800 and any blue-shifted BALs associated with the carbon lines or MgII. To obtain adequate wavelength coverage, we request the COSG140L and STISG230L gratings, centered at 1280A and 2950A, respectively. From the ETC, we expect to achieve excellent S/N will within one orbit per observation. The minimum time needed to achieve decent S/N (20 per resol. elem.) at 1450A and 2800A is 850s and 180s respectively for COSG140L and STISG230L. This assumes the target will be one magnitude fainter by the time of observation. We aim for more conservative values of S/N because the target may fade by the time the observations are taken, making the true signal weaker. One orbit each, with 2220s (2340s) for the COS FUV (STIS NUV) total science exposure, will deliver S/N=30 at 1450A, and S/N=70 at 2800A, including overhead, so we ask for 2 orbits. The source is highly variable, so it is important to our interpretaion of the observations that the orbits be taken back-to-back. Massive Black Holes And Their Host Galaxies 6 false SUPPORTED GALAXY ACCRETION DISK BLR NUCLEUS QUASAR SEYFERT NO J2000 J2000 4.7e-14 erg/s/cm^2/A at rest-frame 1450A COS/FUV Spectroscopic No No G140L 1280 STIS/NUV-MAMA Spectroscopic No No G230L 2376 /private/var/folders/88/_bcxp6y12ldgvw2tpfs6wr_m0000gp/T/OPVisit9113680603389861621.xml 1534483081289 The scheduling data was generated by CASM 26.0. CASM was run in Phase II mode. (Tic-Visit :proposal-id 15604 :visit-id "01" :proposal-version -1 :trans-version "20180409" :date "17-Aug-2018 01:18:01.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 365920 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15604 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 15604 :visit-id "01" :obset-id "A1" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15604 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3191 :al-overhead-at-end 0 :internal-dur-at-end 350 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3546 :pcs-gap 0 ) (Tic-Orbit :proposal-id 15604 :visit-id "01" :orbit-number 2 :pcs-time 333 :si-vis-utilization 3213 :al-overhead-at-end 85 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3546 :pcs-gap 0 ) true 2 0 Exposure time was not supported by the BOT, but the ETC run above gives a SNR = 314.7439 and an electron count rate below the saturation limit of 144,000 electrons.