Slight figure changes. -1034563062 Assigned ID: 1201 ----- Attempting Submission 1 (Thu Jan 16 22:36:19 GMT 2020) ----- HST Phase I Proposal 1201 (SN18aoz.apt) successfully submitted. Receipt: # 1201-1 ----- Attempting Submission 2 (Fri Jan 17 16:36:11 GMT 2020) ----- ----- Attempting Submission 3 (Sat Jan 18 04:42:51 GMT 2020) ----- 3rd submission of Phase II. 1887520409 ----- Attempting Submission 1 (Wed Mar 18 17:06:24 GMT 2020) ----- HST Phase II Proposal 16078 successfully submitted. Receipt: # 16078-1 ----- Attempting Submission 2 (Wed Mar 18 21:41:44 GMT 2020) ----- HST Phase II Proposal 16078 successfully submitted. Receipt: # 16078-2 ----- Attempting Submission 3 (Thu Mar 19 22:08:13 GMT 2020) ----- Late Time Photometry of a Type Ia Supernova with an Early, Red Light Curve Excess Type Ia supernovae (SNe) are essential cosmological distance indicators, but despite their intense study we still do not definitively know their progenitor systems or how exactly the carbon oxygen white dwarf ultimately explodes. We propose to observe the fading optical+NIR light of the nearby SN 2018aoz, which displayed an early, red light curve excess or `bump', but was an otherwise normal SN Ia. This excess may point to a so-called double detonation explosion, shocking of a companion star by the SN ejecta, or an unusual nickel distribution -- or a combination of several of these possibilities. Very late time SN Ia light curves -- only possible with HST -- can distinguish between progenitor and explosion scenarios by constraining the abundance of 57Co and thus can corroborate (or reject) the light curve signatures seen at early times. These observations are essential for building up a clear and comprehensive picture of this otherwise normal SN Ia; similar early time light curve features have only been observable within the last few years, and none with the dramatic early red feature that we witness in SN 2018aoz. We propose to observe the late-time light curve of the Type Ia supernova (SN Ia) SN 2018aoz in one visit with WFC3. In four orbits, we will use F438W, F555W, F600LP, and F110W. For the UVIS filters, a WFC3-UVIS-DITHER-LINE-3PT dithering pattern is used, and for the F110W filter, we use the WFC3-IR-DITHER-LINE pattern. Our team has a strong background in both resolved photometry and supernova studies with HST. PI Sand has extensive experience with HST point source imaging in crowded fields and otherwise, often with his other 'hat' on working on resolved stellar populations in the Local Volume. This includes WFC3, and will translate well to the current proposal where we will be doing faint object photometry, potentially in crowded fields. Our team is filled with very experienced supernova observers, including late time supernova photometry: Sand, Valenti, Drout, Moon. All will participate in the data reduction and analysis at some level, including construction of bolometric light curves and constraining the relevant cobalt abundances. Graduate student R. Amaro will be doing the primary work of this program, trained by the other co-I's, and PI Sand in particular. Graduate student C. Ni at the University of Toronto is leading the early time analysis of SN2018aoz, and will work closely with Amaro on the late time analysis. Stellar Physics 3 false false false false false false false SUPPORTED STAR SUPERNOVA TYPE IA NO J2000 J2000 WFC3/UVIS Imaging No No F438W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F600LP WFC3/IR Imaging No No F110W POS-TARG DITHER 0.135 LINE false false 3 46.84 WFC3-UVIS-DITHER-LINE-3PT 1 false POS-TARG DITHER 0.605 LINE false false 3 41.788 WFC3-IR-DITHER-LINE-3PT 2 false /Users/rach.amaro/Dropbox/HST_mid/OP-cache/SN18aoz_phaseII_v3-v01.xml Timing link suitability includes constraints ([Group (01 02 03) Within 7.0 days]) The scheduling data was generated by CASM 28.0. CASM was run in Phase II mode. Observations of SN2018aoz. We'll take images in the F438W, F555W, F600LP, and F110W filters. (Tic-Visit :proposal-id 16078 :visit-id "01" :proposal-version -1 :trans-version "20191203" :date "18-Mar-2020 11:53:44.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 2598736 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16078 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16078 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2832 :al-overhead-at-end 122 :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 16078 :visit-id "01" :orbit-number 2 :pcs-time 302 :si-vis-utilization 2863 :al-overhead-at-end 116 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3165 :pcs-gap 0 ) true 2 0 /Users/rach.amaro/Dropbox/HST_mid/OP-cache/SN18aoz_phaseII_v3-v02.xml Timing link suitability includes constraints ([Group (01 02 03) Within 7.0 days]) The scheduling data was generated by CASM 28.0. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16078 :visit-id "02" :proposal-version -1 :trans-version "20191203" :date "18-Mar-2020 12:28:33.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1148976 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16078 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16078 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2746 :al-overhead-at-end 0 :internal-dur-at-end 671 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3165 :pcs-gap 0 ) true 1 0 /Users/rach.amaro/Dropbox/HST_mid/OP-cache/SN18aoz_phaseII_v3-v03.xml Timing link suitability includes constraints ([Group (01 02 03) Within 7.0 days]) The scheduling data was generated by CASM 28.0. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16078 :visit-id "03" :proposal-version -1 :trans-version "20191203" :date "18-Mar-2020 11:53:57.0" :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 866240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16078 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16078 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2832 :al-overhead-at-end 116 :internal-dur-at-end 352 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3165 :pcs-gap 0 ) true 1 0