Assigned ID: 213 ----- Attempting Submission 1 (Thu Feb 25 23:33:09 GMT 2010) ----- HST Phase I Proposal 213 (sn2007fo.apt) successfully submitted. ----- Attempting Submission 2 (Fri Feb 26 08:26:36 GMT 2010) ----- HST Phase I Proposal 213 (sn2007fo.apt) successfully submitted. ----- Attempting Submission 1 (Tue Jul 06 15:53:24 GMT 2010) ----- A direct UV search for the progenitor of the nearby type Ib SN 2007fo Understanding the explosive death of massive stars is a key open question in astrophysics. Direct observational information about the pre-explosion properties of supernova progenitors would provide explosion models with a set of initial conditions, and a crucial complement to supernova observations that constrain the explosive outcome. In recent years, identifying the progenitors of the most nearby supernovae in pre-explosion HST images has allowed significant progress in this field. However, this is limited mostly to H-rich type II supernova explosions of red supergiants. The improtant class of stripped (H-poor) type Ib and Ic supernovae, which are especially interesting due to their possible relation to long Gamma-Ray Bursts, remain obscure, with many attempts to discover progenitors yielding only upper limits. The hunt for these elusive progenitors is difficult probably due to a combination of factors: SN Ib/c are intrinsically rare, and their stripped progenitors (probably blue Wolf-Rayet stars) are difficult to detect in archival pre-explosion HST images, mostly obtained in red bands. The nearby type Ib SN 2007fo exploded in NGC 7714, a galaxy with archival imaging uniquely extending to the UV. We have used ground-based Gemini AO imaging of the supernova to localize it on the pre-explosion HST grid, and found that it resides in a complicated area where a single progenitor cannot be pinpointed (though candidates exist). Next, we propose to reimage this location and compare the post-explosion images to archival templates in order to robustly identify the progenitor. Using image-subtraction we will compare the two HST epochs, identify objects that decay or disappear, and thus locate the progenitor of this SN, a very exciting prospect. Failing to detect the progenitor would place strong limits on its luminosity, adding to the growing body of information on SN progenitors. A modest investment of 2 HST orbits has the potential to reveal the first W-R progenitor of a type Ib supernova.
We will observe the location of SN 2007fo in the optical with ACS (1 orbit, split between F814W and F606W) and the UV with WFC3/UVIS (1 orbit split between F390W and F300X). Filters were selected to match available pre-explosion data, and durations were tuned to exceed the sensitivity of the reference data set in all bands, while maximizing orbit use efficiency. RESOLVED STELLAR POPULATIONS 12 false 0.0 0.0 false false false false false false SUPPORTED EXT-STAR SUPERNOVA SUPERNOVA TYPE IB J2000 23 36 14.0000 +02 09 30.00 J2000 ACS/WFC Imaging No No F555W ACS/WFC Imaging No No F814W WFC3/UVIS Imaging No No F390W WFC3/UVIS Imaging No No F300X POS-TARG DITHER 0.265 LINE 0.187 false false 69.05 4 20.67 ACS-WFC-DITHER-BOX 1 false POS-TARG DITHER 0.173 LINE 0.112 false false 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 2 false /home/avishay/hst/2010/sn2007fo/OP-cache/sn2007fo-v01.xml The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12170 :visit-id "01" :proposal-version -1 :trans-version "20100505" :date "06-Jul-2010 17:10:34.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1705344 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12170 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12170 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2901 :al-overhead-at-end 0 :internal-dur-at-end 349 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 /home/avishay/hst/2010/sn2007fo/OP-cache/sn2007fo-v02.xml The scheduling data was generated by CASM 18.3.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12170 :visit-id "02" :proposal-version -1 :trans-version "20100505" :date "06-Jul-2010 17:07:53.0" :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 1732496 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12170 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12170 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2900 :al-overhead-at-end 116 :internal-dur-at-end 670 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0