Comprehensive Chandra, Gemini, JVLA and HST observations of a fast blue optical transient

Science Keywords: Select from 2 to 5 items. 0 Assigned ID: 3797 ----- Attempting Submission 1 (Tue Aug 30 15:03:36 GMT 2022) ----- Joint Chandra/HST This target is not used in this proposal. Submitting with updated filters for epoch 2. -1437833324 ----- Attempting Submission 1 (Wed Sep 28 16:04:05 GMT 2022) ----- ----- Attempting Submission 2 (Fri Feb 03 13:53:52 GMT 2023) ----- ----- Attempting Submission 3 (Thu Apr 27 09:35:39 GMT 2023) ----- HST Phase II Proposal 17238 successfully submitted. Receipt: # 17238-3 ----- Attempting Submission 4 (Fri Apr 28 06:49:59 GMT 2023) ----- ----- Attempting Submission 5 (Mon May 29 08:43:30 GMT 2023) ----- HST Phase II Proposal 17238 successfully submitted. Receipt: # 17238-5 ----- Attempting Submission 6 (Wed May 31 09:36:35 GMT 2023) ----- Generic target no longer used, submitting anyway Comprehensive Chandra, Gemini, JVLA and HST observations of a fast blue optical transient Fast blue optical transients (FBOTs) are a poorly understood class of extragalactic transient. They are at odds with being radioactively powered due to their rapid rise and fall timescales, and are very blue, indicating a high photospheric temperature. Faint FBOTs are now routinely detected, but bright, local events are rare. Only four were followed up with X-ray, optical spectroscopic, and radio observations in the last four years, of which only two had early time multi-wavelength observations. We propose a ToO joint programme (with Chandra, Gemini, JVLA and HST) to follow-up a single bright FBOT in detail. Our proposal will help to discern which features all FBOTs have in common, and will put strong constraints on the nature of the central engine and emission mechanisms. These are target-of-oppourtunity observations of a new fast blue optical transients, spanning two epochs. For epoch (visit) 1: one orbit, consisting of a 1100s observation (with 3-point dither) in F555W, and a 1100s observation (with 3-point dither) in F814W. These observations will be triggered as a non-disruptive ToO, to be excuted within a few weeks of the initial transient detection. The observations will reach reach 3 sigma depths of F555W=27.3 and F814W=26.7 (AB). For epoch (visit) 2: three orbits. All triggered as a non-disruptive ToO, several months after epoch 1. Orbit 1: identical observations to the single orbit of epoch 1, for the purposes of difference imaging and precise transient localisation. Orbit 2: UV observations in F225W and F336W (1100s each, with 3-point dithers). The depths for these observations will be F225W=25.8 and F336W=26.2. These observations will constrain the prescence of high-mass stars at the transient location. Orbit 3: Observations (again totalling 2200s) with a narrow band, and off-band comparison filter, targeting Halpha, to measure the equivalent width of Halpha at the transient location. Because the transient redshift is unknown in advance, we cannot pre-determine the narrow band filter required to capture Halpha. n/a Stellar Physics and Stellar Types 6 false false false false false false false false SUPPORTED STAR SUPERNOVA NO ZTF23AAEOZPP ATLAS23HNK J2000 EXT-STAR SUPERNOVA Newly discovered FBOT WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F225W WFC3/UVIS Imaging No No F336W POS-TARG DITHER 0.135 LINE false false 3 46.84 WFC3-UVIS-DITHER-LINE-3PT 1

false

1682587834883 The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. 1684313646000 109.80000000000001 (Tic-Visit :proposal-id 17238 :visit-id "01" :proposal-version -1 :trans-version "20220630" :date "27-Apr-2023 11:30:34.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 919728 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17238 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17238 :visit-id "01" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2758 :al-overhead-at-end 123 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3157 :pcs-gap 0 ) true 1 0 Awaiting FBOT trigger /tmp/OPVisit10574495113919153980.xml 1685525707080 The scheduling data was generated by CASM 31.0. CASM was run in Phase II mode. (Tic-Visit :proposal-id 17238 :visit-id "02" :proposal-version -1 :trans-version "20220630" :date "31-May-2023 11:35:06.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1946416 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17238 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17238 :visit-id "02" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2656 :al-overhead-at-end 123 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3044 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17238 :visit-id "02" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2645 :al-overhead-at-end 83 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3044 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17238 :visit-id "02" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2628 :al-overhead-at-end 124 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3044 :pcs-gap 0 ) true 3 0 Placeholder filter - to updated once the transient redshift is known, to target Halpha. Placeholder filter - to updated once the transient redshift is known, to target Halpha.