0 Assigned ID: 204 ----- Attempting Submission 1 (Thu Apr 10 16:06:05 GMT 2014) ----- HST Phase I Proposal 204 (iptf13bvn.apt) successfully submitted. ----- Attempting Submission 2 (Fri Apr 11 08:37:18 GMT 2014) ----- This proposal is resubmitted after approval by TTRB of a change request to unify the science goals with those of program GO-13684. Could you please check that the dither patterns for UVIS and ACS were correctly chosen to clear the gap and to remove bad columns and cosmic rays? -2001880744 ----- Attempting Submission 1 (Wed Jul 23 07:47:58 GMT 2014) ----- ----- Attempting Submission 2 (Fri Sep 19 10:30:49 GMT 2014) ----- iPTF13bvn may provide the first conclusive answer to the long-standing question of the nature of hydrogen-deficient supernova (SN) progenitors. The detection of a pre-explosion object in archival images at the SN site led at first to the proposal of a Wolf-Rayet progenitor. However, our hydrodynamical modeling of the SN light curves indicated a much lower progenitor mass, and we proposed an interacting binary system as the progenitor. The proposed HST observations will allow us to verify the disappearance of the pre-explosion object and, most importantly, they will test the binary progenitor scenario through the detection in the UV of a hot companion star. If confirmed, this will be the first firm identification of the progenitor of a hydrogen-deficient SN. These observations will be the deepest available of the host galaxy (NGC 5806) in the requested bands, so they will have high archival value. We have requested that these observations are coordinated with those of program GO-13684. We will obtain deep imaging in two bands of the location of supernova (SN) iPTF13bvn in order to characterize its progenitor system. The observations include one UV band (F225W at WFC3/UVIS), and one optical bands (F814W at ACS/WFC). The UV imaging will allow us to search for the proposed hot companion star of the binary progenitor system. This program will be coordinated with program GO-13684 that will obtain similar imaging of the same field using the F438W and F555W filters with WFC3/UVIS. The optical imaging will reproduce available pre-explosion imaging from 2005 and will help to characterize the surrounding stellar population, estimate extinction and monitor the evolution of the fading SN. Using four orbits (three in UV and one in optical), we will integrate during nearly 8900 seconds in F225W, and ~2300 s in F814W. According to ETC runs, these exposure times will reach detection limits (Vega magnitudes) of F225W~27 mag, and F814W~28 mag, with S/N~3. This is enough to probe the properties of the proposed companion star, and to detect the disappearance of the exploding (primary) star. In order to avoid confusion with flux from the SN itself, we requested that the observations are carried out after May 15, 2015 (with visibility constraints, this actually implies after June 10). At that stage the contribution from the SN is expected to be small but non-negligible. However, as pointed out in out Phase I proposal, the SN colors are expected to be much redder than those of the hot companion star, which will allow us to provide a robust detection. The WFC3/UVIS imaging in F225W were divided into three integrations, one per orbit, using a linear dither pattern to ensure covering the chip gap and cleaning cosmic rays and bad pixels, as well as improving the psf sampling. There is no need to avoid droplets using larger dither steps because we do not require <1% photometric accuracy. The pointing was centered at the nucleus of the host galaxy (NGC 5806) and the UVIS-CENTER aperture was chosen. With that, we can obtain full coverage of the host galaxy for future reference. According to the BOT, the FOV is free of dangerously bright objects. Each exposure requires a post-flash lamp of 5 e-/pix to increase the background level to ~12 e-/pix and so to mitigate CTE losses. The F225W observations were placed in the first visit of this program because they are critical to our science goals. Optical imaging with ACS/WFC and the F814W filter were divided into three dithered integrations. They span one orbit that was placed in visit 2. The full detector is used and the pointing is centered at the host-galaxy nucleus to obtain a complete image of the galaxy. With the requested individual integration times, the optical observations require no post-flash lamp. Some objects in the FOV are bright enough to saturate (15 objects according to the BOT), but they are all located far from the SN and in the outskirts of the galaxy. UV and optical observations were split into separate visits to improve schedulability. However, it would be preferable to have both of them carried out at similar times in order to obtain accurate colors and monitor the SN evolution. That is why we added the loose constraint that visit 2 (optical) is conducted within one month of visit 1 (UV). For the same reason, it would also be ideal to schedule this program within one month of program GO-13684. HOT STARS Default false true false false false SUPPORTED STAR SUPERNOVA SUPERNOVA TYPE IB This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 WFC3/UVIS Imaging No No F225W ACS/WFC Imaging No No F435W ACS/WFC Imaging No No F555W ACS/WFC Imaging No No F814W POS-TARG MOSAIC DITHER 4 2.414 We have selected this patter to cover the gap between chips and so to obtain full coverage of the host galaxy. WFC3-UVIS-DITHER-BOX false 81.785 true 0.112 0.173 3 85.759 POS-TARG WFC3-UVIS-GAP-LINE 23.884 2 false POS-TARG DITHER 3.011 This pattern was chosen to cover the gap and thus obtain a full image of the host galaxy. LINE false false 3 85.28 ACS-WFC-DITHER-LINE 3 false 1411120486731 Timing link suitability includes constraints ([02 After 01 by at most 30.0 days]) The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. /negra2/trabajo/observacion/propuestas/hst_cycle22/phase2/OP-cache/iptf13bvn_p2_v02-v01.xml This is the critical visit since it contains the UV observations that will serve to search for the companion of the progenitor of iPTF13bvn. This visit comprises three orbits, each with one exposure in the F225W band using WFC3/UVIS. We require that the SN has faded enough when these observations are done, so we have placed a loose constraint of scheduling this visit after May 15, 2015. We would like to have this visit executed within one month of the observations of program GO-13684 in order to obtain accurate colors. (Tic-Visit :proposal-id 13822 :visit-id "01" :proposal-version -1 :trans-version "20140605" :date "19-Sep-2014 18:54:46.0" :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 866240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13822 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13822 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2889 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13822 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3000 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) (Tic-Orbit :proposal-id 13822 :visit-id "01" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3000 :al-overhead-at-end 120 :internal-dur-at-end 352 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) true 3 0 We will obtain the F225W exposures with a three-point dither pattern to cover the chip gap and to avoid bad pixels/columns and cosmic rays. Each exposure requires a post-flash lamp of 5e/pix to increase the backgroud level to ~12e/pix and so to mitigate CTE losses. The Aperture was chosen as UVIS-CENTER and the coordinates are those of the nucleus of NGC 5806. This provides complete coverage of the galaxy in the FOV. 1411120488843 /negra2/trabajo/observacion/propuestas/hst_cycle22/phase2/OP-cache/iptf13bvn_p2_v02-v02.xml Timing link suitability includes constraints ([02 After 01 by at most 30.0 days]) The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. This visit contains the optical reference imaging with filter F814W that will help determine if the object seen prior to the SN explosion has disappeared. In order to obtain reliable UV-optical colors, we require that visit 2 is carried out within one month of visit 1. This visit includes one orbit with three dithered exposures in the F814W band using WFC3/UVIS. (Tic-Visit :proposal-id 13822 :visit-id "02" :proposal-version -1 :trans-version "20140605" :date "19-Sep-2014 18:54:48.0" :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 852672 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13822 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13822 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2889 :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 3222 :pcs-gap 0 ) true 1 0 We will obtain the F814W exposures with a three-point dither pattern to avoid bad pixels/columns and cosmic rays. No post-flash exposure is required. The complete detector is used and the pointing is centered at the nucleus of the host galaxy in order to obtain full coverage of the galaxy.