0 Assigned ID: 4011 ----- Attempting Submission 1 (Mon May 22 02:01:45 GMT 2023) ----- HST Phase I Proposal 4011 successfully submitted. Receipt: # 4011-1 Quick edit to fix a parameter I accidentally changed before resubmitting -851786769 ----- Attempting Submission 1 (Tue May 30 18:41:22 GMT 2023) ----- HST Phase II Proposal 17314 successfully submitted. Receipt: # 17314-1 ----- Attempting Submission 2 (Thu Jun 01 15:33:58 GMT 2023) ----- HST Phase II Proposal 17314 successfully submitted. Receipt: # 17314-2 ----- Attempting Submission 3 (Thu Jun 01 15:46:38 GMT 2023) ----- When a star ventures close to a supermassive black hole, it is shredded and consumed in a tidal disruption event (TDE). In a poorly understood fraction of TDEs, the star is not fully consumed, but instead is only partially disrupted and continues orbiting the star. It is repeatedly partially disrupted each time it reaches pericenter, causing a periodic transient. Partial disruption events are key for understanding SMBH growth and feeding and the rate of tidal disruption events, among other subjects. However, only a handful of candidate partial TDEs are known. In the last few days, we have discovered a bonafide partial TDE, AT2020vdq. This event is remarkably energetic, with potential super-Eddington accretion during the present flare and evidence for fast wind launching. We propose two orbits of HST/STIS observations to obtain NUV and FUV spectra for this partial TDE. UV spectra of TDE are sensitive to the presence of outflows near the SMBH and will allow us to make the first strong statements on the evolution and dynamics of partial TDEs. We aim to obtain FUV and NUV spectra for a UV-bright TDE. We were allocated two orbits for this program. We require that the observations occur before June 21 so that the TDE is sufficiently UV bright. We do not expect the TDE to be so UV bright as to require bright target acquisition procedures. Our observation begins with a 20 sec acquisition using the diffuse target procedure, as we aim to acquire a point source on top of diffuse emission from a galaxy. We then obtain a FUV spectrum of the source, split into to exposures so as to ensure no unused orbital visibility. We finally obtain a NUV of the source. Jean Somalwar and Prof. Vikram Ravi have both worked extensively on multiwavelength observations of tidal disruption events. They are leading an effort to discover TDEs in the VLA Sky Survey and have published multiple papers on these events and their multiwavelength signatures. They are also been involved with searches for TDEs in the optical and are co-authors on multiple papers that analyze optically discovered TDEs. Jean Somalwar also has extensive experience working with HST observations (HST/COS and HST/ACS). Supermassive Black Holes and Active Galaxies Galaxies 0 false SUPPORTED GALAXY ACCRETION DISK BLR NUCLEUS WIND These coordinates are from TNS as reported by the ZTF survey and are the location of the transient optical flare. They are coincident with the location of the galactic nucleus from public optical imaging (e.g., Legacy survey; the offset from the reported coordinates of the galaxy nucleus is ~0.1"). We assume a uncertainty of 0.3" in both the ra and dec because this is the largest typical uncertainty reported by ZTF, although we expect that this estimate is conservative. J2000 J2000 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 1685633613419 The scheduling data was generated by CASM 31.0. CASM was run in Phase II mode. /Users/jeansomalwar/Documents/OP-cache/DDT_2020vdq_phase2-v01.xml (Tic-Visit :proposal-id 17314 :visit-id "01" :proposal-version -1 :trans-version "20220630" :date "01-Jun-2023 08:33:33.0" :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 261408 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17314 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17314 :visit-id "01" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2845 :al-overhead-at-end 0 :internal-dur-at-end 113 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3238 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17314 :visit-id "01" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2845 :al-overhead-at-end 0 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3238 :pcs-gap 0 ) true 2 0 Acquisition of TDE. FUV spectrum of UV-bright TDE. The ETC uses the most recent UV flux of this source from the Swift telescope, assuming that the source has faded according to typical TDE fade timescales. We have split this exposure into two exposures to optimally fill our two orbits. FUV spectrum of UV-bright TDE. The ETC uses the most recent UV flux of this source from the Swift telescope, assuming that the source has faded according to typical TDE fade timescales. We have split this exposure into two exposures to optimally fill our two orbits. NUV spectrum of UV-bright TDE. The ETC uses the most recent UV flux of this source from the Swift telescope, assuming that the source has faded according to typical TDE fade timescales.