0 Assigned ID: 357 ----- Attempting Submission 1 (Fri Mar 06 00:29:48 GMT 2020) ----- Trigger for GRB211106A - target coordinates and information added 1921563486 ----- Attempting Submission 1 (Fri Jun 12 18:34:38 GMT 2020) ----- HST Phase II Proposal 16303 successfully submitted. Receipt: # 16303-1 ----- Attempting Submission 2 (Fri Jun 12 19:56:12 GMT 2020) ----- ----- Attempting Submission 3 (Thu Nov 18 14:53:18 GMT 2021) ----- HST Phase II Proposal 16303 successfully submitted. Receipt: # 16303-3 ----- Attempting Submission 4 (Thu Nov 18 15:20:45 GMT 2021) ----- HST Phase II Proposal 16303 successfully submitted. Receipt: # 16303-4 ----- Attempting Submission 5 (Thu Nov 18 20:04:52 GMT 2021) ----- The joint gravitational wave and electromagnetic detections of the binary neutron star (BNS) merger GW170817 ushered in a new era of astrophysics. In the UV/optical/NIR the emission (a "kilonova") was powered by radioactive decay of nuclei produced via r-process nucleosynthesis. In the gamma-ray, X-ray, and radio the emission was instead powered by an off-axis jet typical of short gamma-ray bursts (SGRBs); this connection was previously supported by the HST detection of a kilonova in the short GRB130603B. With only a single joint GW-EM detection and a single kilonova detection in an SGRB, the key frontier is to begin to map the distribution of merger outcomes: ejecta mass, velocity, geometry, and nucleosynthetic yields. Here we propose to achieve this goal with HST observations of a kilonova associated with an SGRBs; observations of kilonovae in SGRBs are essential because the orientation is well known (face-on, along the binary's angular momentum axis) and the LIGO/Virgo Observing Run 3 has not yielded joint GW-EM detections. Such a study can only be achieved with the sensitivity and resolution of HST, and it matches one of the "special initiatives", namely deep NIR monitoring that is essential for informing future JWST follow-ups ("JWST Preparatory Observations"). We request 10 orbits for 1 SGRB event. The HST observations will be supported by approved programs at Chandra, VLA, ALMA, Gemini, Keck, Magellan, MMT that will provide the targets, cover optical and early NIR follow-up to establish the baseline behavior, and complete the multi-wavelength picture of the event. Given the broad interest in this topic we waive the proprietary period. Triggered target is GRB211106A at z=0.1, with observations for this redshift range as described below. To determine the expected apparent brightness of the kilonova for the expected range of ejecta masses (0.01-0.1 Msun), and to inform the choice of filters, we convolve the kilonova models of Barnes & Kasen (2013) as a function of redshift with the ACS/F814W, WFC3/F110W, and WFC3/F160W filter response functions. We calculate the resulting apparent brightness in two rest-frame times of 4 days (peak) and 10 days (post-maximum). The actual observer-frame times for the two HST epochs will therefore be 4x(1+z) days and 10x(1+z) days, where the redshift will be known prior to triggering the HST observations from rapid ground-based follow-up. The choice of filters is designed to straddle the break at 1 micron in the rest-frame, in order to capture the unusually red color of a kilonova. We base our HST trigger criteria and time request on the model with 0.01 Msun so that we can probe the wide range of ejecta masses predicted by numerical simulations (rather than just the bright upper bound of 0.1sun); this will allow any non-detections to place meaningful constraints on the r-process yield. Epoch 1 (4x(1+z) days): We find that at z<=0.2 it is advantageous to use the ACS/F814W and WFC3/F110W filters, which give the best combination of sensitivity (5sigma=27.7 and 27.5 AB mag in 2 orbits each, respectively, using the ACS and WFC3 ETCs) and color contrast (F814W-F110W=1.6-2 AB mag). The afterglow color in these filters will be much bluer, F814W-F110W=0.3 AB mag, so a kilonova origin can be robustly demonstrated. At z=0.2-0.4 we will instead use the WFC3/F110W and F160W filters to capture the spectral break (5sigma=26.3 AB mag for F160W in 2 orbits). The resulting color is F110W-F160W=0.6-1.2 AB mag, compared to a bluer color for the afterglow, F110W-F160W=0.3 AB mag. The kilonova emission for 0.1 Msun can be detected to z=0.7, but we truncate our trigger criteria at z=0.4 to be able to detect the emission in the case of 0.01 Msun. Epoch 2 (10x(1 + z) days): In the second epoch we will only observe in a single filter redward of the 1 micron break since we are only concerned with demonstrating a rapid decline that will help to robustly determine the ejecta mass (i.e., the unusually red color will already be established with the first epoch near peak). This will require 2 orbits in F110W (z<=0.2) or F160W (z=0.2-0.4). In this case, if the ejecta mass is 0.01 Msun we will obtain a deep upper limit that will establish the expected rapid fading, while in the case of 0.1 Msun we will have a second detection. Templates (>1 month): We will acquire template images after the kilonova emission has faded away that match the exposure time and filters of the earlier epochs. This will therefore require a total of 4 orbits (2 orbits in each filter). We note, however, that in the case of 0.01 Msun a non-detection in the second epoch could be used as a template in one of the two filters (F110W or F160W depending on the redshift), meaning that the final observation will require only 2 orbits. Since we do not know the ejecta mass in advance we request 4 orbits for the final epoch, but may use only 2 orbits. This will be known following epoch 2. Dr. Edo Berger is an expert in the study of astrophysical transients, including short gamma-ray bursts and gravitational wave events, which are the focus of this Cycle 28 proposal. Dr. Berger has been the PI of 6 previous HST programs (10616, 10641, 10908, 13022, 15329, 15964), and is the supervisor of several graduate students and postdoctoral fellows who have been PIs of 10 HST programs over the past decade. The proposed program includes 4 of Dr. Berger's thesis students (Patton, Gomez, Villar, Eftekhari). Raffaella Margutti is the PI of supporting Chandra and NuSTAR programs. Wen-fai Fong and Tarraneh Eftekhari are the PIs of supporting VLA and ALMA programs, as well as Keck and Gemini programs. Petter Blanchard is the PI of an MMT program (through Northwestern). Philip Cowperthwaite is the PI of a supporting Magellan program (through Carnegie). Griffin Hosseinzadeh is the PI of supporting Magellan and MMT programs (through Harvard). Matt Nicholl provides UK telescope access. Ryan Chornock provides access to MDM. Graduate students Victoria (Ashley) Villar, Sebastian Gomez, Locke Patton, and Tarraneh Eftekhari are students of the PI and will lead various aspects of the HST and supporting observations data analysis and interpretation. They are all experienced with HST data analysis. Chris Fryer, Dan Kasen, and Brian Metzger are experts in theoretical studies of binary neutron star mergers and radiative transfer of r-process material, and they will support the interpretation of the resulting HST data. Our team played a key role in the discovery of the optical counterpart of GW170817 and in the subsequent study of its multi-wavelength emission, including through HST Cycle 25 program 15329. The results of our work were published in 18 papers over the past year, so we are well positioned to rapidly and expertly publish the results of the proposed HST observations. Specifically, the HST Cycle 25 data were used in 5 publications in 2017-2019. Stellar Physics and Stellar Types 0 false false false false true false false false SUPPORTED UNIDENTIFIED GAMMA RAY EMITTER NO Short GRB at z~0.1; observations in ACS/F814W and WFC3/F110W as planned in the original proposal. J2000 WFC3/IR Imaging No No F110W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F110W WFC3/IR Imaging No No F160W POS-TARG DITHER 0.262 LINE 0.192 false false 68.14 4 18.39 ACS-WFC-DITHER-BOX 1 false POS-TARG DITHER 0.572 LINE 0.365 false false 74.653 4 18.528 WFC3-IR-DITHER-BOX-MIN 2 false 1637248598128 Timing link suitability includes constraints ([02 After 01 by 6.0 to 9.0 days]) The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. /Users/edoberger/Proposals/HST/Cycle28/Kilonova-SGRB/OP-cache/sgrb211106a_trigger-v01.xml (Tic-Visit :proposal-id 16303 :visit-id "01" :proposal-version -1 :trans-version "20210514" :date "18-Nov-2021 10:16:37.0" :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 4293216 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16303 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 16303 :visit-id "01" :obset-id "A1" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16303 :visit-id "01" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2758 :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 3333 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16303 :visit-id "01" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2732 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16303 :visit-id "01" :orbit-number 3 :pcs-time 383 :si-vis-utilization 2658 :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 3333 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16303 :visit-id "01" :orbit-number 4 :pcs-time 392 :si-vis-utilization 2658 :al-overhead-at-end 0 :internal-dur-at-end 329 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) true 4 0 This visit is a target of opportunity triggered on a Short GRB of z < 0.2. 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CASM was run in Phase II mode. /Users/edoberger/Proposals/HST/Cycle28/Kilonova-SGRB/OP-cache/sgrb211106a_trigger-v02.xml (Tic-Visit :proposal-id 16303 :visit-id "02" :proposal-version -1 :trans-version "20210514" :date "18-Nov-2021 10:16:39.0" :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 2019424 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16303 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16303 :visit-id "02" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2658 :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 3333 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16303 :visit-id "02" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2658 :al-overhead-at-end 0 :internal-dur-at-end 329 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3333 :pcs-gap 0 ) true 2 0 This visit is a target of opportunity triggered on a Short GRB of z < 0.2. This is our second epoch and should be triggered at 10 x (1+z) days after the GRB detection. 1637248602006 Timing link suitability includes constraints ([03 After 02 by 20.0 to 30.0 days]) The scheduling data was generated by CASM 29.2. 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This is our template epoch and should be triggered at >1 month after the GRB detection.