Understanding the Progenitor Systems, Explosion Mechanisms, and Cosmological Utility of Type Ia Supernovae

Understanding the Progenitor Systems, Explosion Mechanisms, and Cosmological Utility of Type Ia Supernovae Despite spending >2000 HST orbits on observations of high-redshift Type Ia supernovae (SN Ia), where observations at z > 1 exclusively probe the rest-frame UV, there is only one published high-quality true UV spectrum of a SN Ia within a week of maximum brightness - and this spectrum was from Cycle 1 in 1992. We propose to obtain STIS spectroscopy of three nearby SN Ia from about a week before maximum brightness until about 20 days after maximum brightness. By obtaining spectra every 4 days, we will be able to model the ejecta abundances as the photosphere recedes with time - like a CAT scan. Since the UV SED is extremely sensitive to several parameters like progenitor metallicity, intermediate mass element generation, and 56Ni mixing, these data (in conjunction with OIR observations obtained from the ground) will be the most constraining yet for SN Ia models. Similar data have never been obtained. In addition to furthering our understanding of SN Ia progenitor systems and explosions, we will use these data to directly improve the utility of SN Ia as cosmological distance indicators. These SN Ia will be the best observed and best studied SN Ia ever. This is our best opportunity to further our understanding of these objects.

The sequence of observations for the TOO is as follows: 7 epochs. The first epoch is 2 orbits, the rest are 1 orbit. The cadence is spectra on Day 0, 4, 8, 12, 16, 20, 28. where day 0 is the first HST observation. We used a bracket of 2 days/epoch but ideally would like the observations scheduled on the first day. HOT STARS 12 false 0.0 0.0 false false false false SUPPORTED EXT-STAR SUPERNOVA TYPE IA J2000 EXT-STAR SUPERNOVA TYPE IA TOO STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 Timing link suitability includes constraints ([02 After 01 by 4.0 to 5.0 days] [03 After 01 by 8.0 to 9.0 days] [04 After 01 by 12.0 to 13.0 days] [05 After 01 by 16.0 to 17.0 days] [06 After 01 by 20.0 to 21.0 days] [07 After 01 by 28.0 to 29.0 days]) The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. If is is possible to decrease the SCHEDABILITY, then please increase the exposure time to exposure #3 the second G230L exposure in orbit #2 (Tic-Visit :proposal-id 12592 :visit-id "01" :proposal-version -1 :trans-version "20110825" :date "05-Dec-2011 09:24:15.0" :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 321648 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12592 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12592 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2669 :al-overhead-at-end 0 :internal-dur-at-end 115 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3021 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12592 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2746 :al-overhead-at-end 0 :internal-dur-at-end 603 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3021 :pcs-gap 0 ) true 2 0 TOO ).1 for 14th mag star yields a s/n ~50 Time to saturation is 15 seconds. Timing link suitability includes constraints ([02 After 01 by 4.0 to 5.0 days]) The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. please try to schedule as early in the AFTER window as possible. (Tic-Visit :proposal-id 12592 :visit-id "02" :proposal-version -1 :trans-version "20110825" :date "05-Dec-2011 09:24:17.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 234656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12592 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12592 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2867 :al-overhead-at-end 0 :internal-dur-at-end 662 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 TOO Timing link suitability includes constraints ([03 After 01 by 8.0 to 9.0 days]) The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. please try to schedule as early in the AFTER window as possible. (Tic-Visit :proposal-id 12592 :visit-id "03" :proposal-version -1 :trans-version "20110825" :date "05-Dec-2011 09:24:19.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 234656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12592 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12592 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2867 :al-overhead-at-end 0 :internal-dur-at-end 662 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 TOO Timing link suitability includes constraints ([04 After 01 by 12.0 to 13.0 days]) The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. please try to schedule as early in the AFTER window as possible. (Tic-Visit :proposal-id 12592 :visit-id "04" :proposal-version -1 :trans-version "20110825" :date "05-Dec-2011 09:24:20.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 234656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12592 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12592 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2867 :al-overhead-at-end 0 :internal-dur-at-end 662 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 TOO Timing link suitability includes constraints ([05 After 01 by 16.0 to 17.0 days]) The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. please try to schedule as early in the AFTER window as possible. (Tic-Visit :proposal-id 12592 :visit-id "05" :proposal-version -1 :trans-version "20110825" :date "05-Dec-2011 09:24:22.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 234656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12592 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12592 :visit-id "05" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2867 :al-overhead-at-end 0 :internal-dur-at-end 662 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 TOO Timing link suitability includes constraints ([06 After 01 by 20.0 to 21.0 days]) The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. please try to schedule as early in the AFTER window as possible. (Tic-Visit :proposal-id 12592 :visit-id "06" :proposal-version -1 :trans-version "20110825" :date "05-Dec-2011 09:24:23.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 234656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12592 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12592 :visit-id "06" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2867 :al-overhead-at-end 0 :internal-dur-at-end 662 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 TOO Timing link suitability includes constraints ([07 After 01 by 28.0 to 29.0 days]) The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. please try to schedule as early in the AFTER window as possible. (Tic-Visit :proposal-id 12592 :visit-id "07" :proposal-version -1 :trans-version "20110825" :date "05-Dec-2011 09:24:25.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 234656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12592 :visit-id "07" :obset-id "07" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12592 :visit-id "07" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2867 :al-overhead-at-end 0 :internal-dur-at-end 662 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 TOO Timing link suitability includes constraints ([12 After 11 by 4.0 to 5.0 days] [13 After 11 by 8.0 to 9.0 days] [14 After 11 by 12.0 to 13.0 days] [15 After 11 by 16.0 to 17.0 days] [16 After 11 by 20.0 to 21.0 days] [17 After 11 by 28.0 to 29.0 days]) The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. If is is possible to decrease the SCHEDABILITY, then please increase the exposure time to exposure #3 the second G230L exposure in orbit #2 (Tic-Visit :proposal-id 12592 :visit-id "11" :proposal-version -1 :trans-version "20110825" :date "05-Dec-2011 09:28:29.0" :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 395312 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12592 :visit-id "11" :obset-id "11" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12592 :visit-id "11" :orbit-number 1 :pcs-time 241 :si-vis-utilization 2669 :al-overhead-at-end 0 :internal-dur-at-end 115 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3022 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12592 :visit-id "11" :orbit-number 2 :pcs-time 176 :si-vis-utilization 2808 :al-overhead-at-end 0 :internal-dur-at-end 742 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3022 :pcs-gap 0 ) true 2 0 TOO ).1 for 14th mag star yields a s/n ~50 Time to saturation is 15 seconds. Timing link suitability includes constraints ([12 After 11 by 4.0 to 5.0 days]) The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. please try to schedule as early in the AFTER window as possible. (Tic-Visit :proposal-id 12592 :visit-id "12" :proposal-version -1 :trans-version "20110825" :date "05-Dec-2011 09:25:55.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 234656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12592 :visit-id "12" :obset-id "12" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12592 :visit-id "12" :orbit-number 1 :pcs-time 241 :si-vis-utilization 2767 :al-overhead-at-end 0 :internal-dur-at-end 682 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3022 :pcs-gap 0 ) true 1 0 TOO Timing link suitability includes constraints ([13 After 11 by 8.0 to 9.0 days]) The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. please try to schedule as early in the AFTER window as possible. (Tic-Visit :proposal-id 12592 :visit-id "13" :proposal-version -1 :trans-version "20110825" :date "05-Dec-2011 09:25:56.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 234656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12592 :visit-id "13" :obset-id "13" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12592 :visit-id "13" :orbit-number 1 :pcs-time 241 :si-vis-utilization 2767 :al-overhead-at-end 0 :internal-dur-at-end 682 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3022 :pcs-gap 0 ) true 1 0 TOO Timing link suitability includes constraints ([14 After 11 by 12.0 to 13.0 days]) The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. please try to schedule as early in the AFTER window as possible. (Tic-Visit :proposal-id 12592 :visit-id "14" :proposal-version -1 :trans-version "20110825" :date "05-Dec-2011 09:24:34.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 234656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12592 :visit-id "14" :obset-id "14" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12592 :visit-id "14" :orbit-number 1 :pcs-time 241 :si-vis-utilization 2767 :al-overhead-at-end 0 :internal-dur-at-end 682 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3022 :pcs-gap 0 ) true 1 0 TOO Timing link suitability includes constraints ([15 After 11 by 16.0 to 17.0 days]) The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. please try to schedule as early in the AFTER window as possible. (Tic-Visit :proposal-id 12592 :visit-id "15" :proposal-version -1 :trans-version "20110825" :date "05-Dec-2011 09:24:35.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 234656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12592 :visit-id "15" :obset-id "15" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12592 :visit-id "15" :orbit-number 1 :pcs-time 241 :si-vis-utilization 2767 :al-overhead-at-end 0 :internal-dur-at-end 682 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3022 :pcs-gap 0 ) true 1 0 TOO Timing link suitability includes constraints ([16 After 11 by 20.0 to 21.0 days]) The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. please try to schedule as early in the AFTER window as possible. (Tic-Visit :proposal-id 12592 :visit-id "16" :proposal-version -1 :trans-version "20110825" :date "05-Dec-2011 09:24:37.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 234656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12592 :visit-id "16" :obset-id "16" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12592 :visit-id "16" :orbit-number 1 :pcs-time 241 :si-vis-utilization 2767 :al-overhead-at-end 0 :internal-dur-at-end 682 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3022 :pcs-gap 0 ) true 1 0 TOO Timing link suitability includes constraints ([17 After 11 by 28.0 to 29.0 days]) The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. please try to schedule as early in the AFTER window as possible. (Tic-Visit :proposal-id 12592 :visit-id "17" :proposal-version -1 :trans-version "20110825" :date "05-Dec-2011 09:24:38.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 234656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12592 :visit-id "17" :obset-id "17" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12592 :visit-id "17" :orbit-number 1 :pcs-time 241 :si-vis-utilization 2767 :al-overhead-at-end 0 :internal-dur-at-end 682 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3022 :pcs-gap 0 ) true 1 0 TOO If is is possible to decrease the SCHEDABILITY, then please increase the exposure time to exposure #3 the second G230L exposure in orbit #2 (Tic-Visit :proposal-id 12592 :visit-id "11" :proposal-version -1 :trans-version "20110825" :date "05-Dec-2011 09:28:29.0" :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 395312 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12592 :visit-id "11" :obset-id "11" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12592 :visit-id "11" :orbit-number 1 :pcs-time 241 :si-vis-utilization 2669 :al-overhead-at-end 0 :internal-dur-at-end 115 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3022 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12592 :visit-id "11" :orbit-number 2 :pcs-time 176 :si-vis-utilization 2808 :al-overhead-at-end 0 :internal-dur-at-end 742 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3022 :pcs-gap 0 ) false 2 0 TOO ).1 for 14th mag star yields a s/n ~50 Time to saturation is 15 seconds.