13685( 2) - 24-Jul-2014 12:05:45 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13685 Version: 2 Check-in Time: 24-Jul-2014 12:05:45 STScI Edit Number: 0 Title Emission line imaging of the bipolar shell in the Helium Nova V445 Puppis ------------------------------------------------------------------------------------ Type Cycle GO 22 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Danny Steeghs The University of Warwick Y CoI: Dr. Patrick Woudt University of Cape Town N CoI: Dr. Matthew Schurch University of Cape Town N CoI: Dr. Margarita Karovska Smithsonian Institution Astrophysical N Observatory CoI: Dr. Sumner G. Starrfield Arizona State University N CoI: Prof. Thomas R. Marsh The University of Warwick N CoI: Prof. Brian Warner University of Cape Town N CoI: Prof. Paul Groot Radboud Universiteit Nijmegen N ------------------------------------------------------------------------------------ Abstract Explosive detonations on the surfaces of accreting white dwarfs play a key role in establishing viable progenitor pathways towards Type Ia supernova explosions. If the white dwarf is accreting hydrogen deficient material, helium shell-flash driven eruptions can occur on its surface. Thus far only one such helium nova event has been observed in Nova Puppis 2000 = V445 Pup. We have discovered an expanding bipolar shell involving fast moving ejecta of He-rich material surrounding this binary. This used state of art ground-based AO imaging and IFU spectroscopy. However, we have now reached the limit of what can be done from the ground and therefore request high spatial resolution HST imaging of the ejecta in V445 Pup. These Cycle 22 observations are the 2nd epoch of our HST campaign, to be compared with the existing Cycle 20 data. These narrow band images will allow us to map the expanding ejecta in the [OII], [OIII] and HeI lines, to be directly compared with kinematical measurements based on the same lines. This will allow us to determine a robust distance using the expansion parallax method and study the ionisation structure of the shells and knots we have seen in our broadband AO images. Splitting the observations over two cycles is necessary in order to provide sufficient baseline to accurately measure the on-sky expansion which is estimated to proceed at an angular speed of 0.3"/year. ------------------------------------------------------------------------------------ Observations Description ------------------------ Our imaging targets an extended source resolving the ejecta of a nova eruption in 2000 using WPFC3/UVIS. The filters are chosen to target previously detected emission lines covering [OIII] with F502N, [OII] with FQ727N and HeI with F680N. We have supporting ground-based data that map the kinematics of these lines using IFU spectroscopy while the target position is accurately known from recent ground-based imaging. All our exposures use the same 3-point dither pattern to improve sampling and permit cosmic ray rejection. Exposure times are scaled to reflect the observed 13685( 2) - 24-Jul-2014 12:05:45 - [ 2] relative line strengths while at the same time pack the 2-orbit long visit efficiently. Thus F680N receives the longests exposure time and takes up the whole of orbit 1, followed by F502N and some short FQ727N exposures in orbit 2. We have chosen the optimal UVIS aperture for our F502N and F680N exposures, while the FQ727N exposures will use the quadrant D sub-array only in sync with the filter and to save some overheads. We have decided to enable the post-FLASH as an extra option, since we believe our relatively short exposure times with narrow-band filters will benefit from this procedure. We verified background levels using the ETC and request a post-flash level of 15e for the F502N and FQ727 exposures as these have the lowest background per exposure (<5e), while 10e is sufficient for the F680N exposure (with ~5e). -------- Realtime Justification -------- N/A ------ Calibration Justification ------- N/A --------- Additional Comments ---------- This set of images is a repeat of the sequence of filters observed in Cycle 20 ------------------------------------------------------------------------------------ 13685( 2) - 24-Jul-2014 12:05:45 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 V-V445-PUP STAR, CLASSICAL NOVA, RA=07H37M56.9000S +/- 0.1", J2000 V = 19.74 +/- 0.1 J=17.36 +/- 0.07 EMISSION LINE NEBULA DEC=-25D56'58.90" +/- 0.1" Reference Frame: ICRS Comments: Position determined from recent good seeing CCD imaging at the Magellan telescope with a WCS referenced to ICRS. Note that target is currently significantly fainter than on DSS plates as the nova eruption casued extensive local extinction. ------------------------------------------------------------------------------------------------------------------------------------ 13685( 2) - 24-Jul-2014 12:05:45 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE-3PT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.135 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern YES Pattern_Comments: Standard 3-pt line dither with centering enabled ------------------------------------------------------------------------------------------------------------------------------------ 13685( 2) - 24-Jul-2014 12:05:45 - [ 5] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: Cycle 22 epoch, to be matched with Cycle 20 imaging Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 V-V445-PUP WFC3/UVI ACCUM UVIS F680N FLASH=15.0 1 879 S PATTERN 2 1 S (2637 S) Comments: F680N over 3pt dither post-FLASH of 10e to reflect low expected background ------------------------------------------------------------------------------------------------------------------------------------ 2 V-V445-PUP WFC3/UVI ACCUM UVIS F502N FLASH=15 1 540 S PATTERN 2 2 S (1620 S) Comments: F502N over 3pt dither post-FLASH of 15e to reflect low expected background ------------------------------------------------------------------------------------------------------------------------------------ 3 V-V445-PUP WFC3/UVI ACCUM UVIS-QUAD FQ727N FLASH=15 1 207 S (621 PATTERN 2 3 S -SUB S) Comments: FW727 over 3pt dither, quadrant D sub-array post-FLASH of 15e to reflect low expected background ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ V-V445-PUP 1 WFC3/UVI ACCUM UVIS F680N 1 none none none 1 N/A S V-V445-PUP 1 WFC3/UVI ACCUM UVIS F680N 2 none none none 1 N/A S V-V445-PUP 1 WFC3/UVI ACCUM UVIS F680N 3 none none none 1 N/A S V-V445-PUP 2 WFC3/UVI ACCUM UVIS F502N 1 none none none 2 N/A S V-V445-PUP 2 WFC3/UVI ACCUM UVIS F502N 2 none none none 2 N/A S V-V445-PUP 2 WFC3/UVI ACCUM UVIS F502N 3 none none none 2 N/A S V-V445-PUP 3 WFC3/UVI ACCUM UVIS-QUA FQ727N 1 none none none 2 N/A S D-SUB 13685( 2) - 24-Jul-2014 12:05:45 - [ 6] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ V-V445-PUP 3 WFC3/UVI ACCUM UVIS-QUA FQ727N 2 none none none 2 N/A S D-SUB V-V445-PUP 3 WFC3/UVI ACCUM UVIS-QUA FQ727N 3 none none none 2 N/A S D-SUB 13685( 2) - 24-Jul-2014 12:05:45 - [ 7] Summary Form for Proposal 13685 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS, UVIS-QUAD-SUB ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=15, FLASH=15.0 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 2 1, PATTERN 2 2, PATTERN 2 3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F502N, F680N, FQ727N ------------------------------------------------------------------------------------------------------------------------------------ Target Names V-V445-PUP ------------------------------------------------------------------------------------------------------------------------------------