12858( 3) - 06-Nov-2012 13:33:02 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 12858 Version: 3 Check-in Time: 06-Nov-2012 13:33:02 STScI Edit Number: 0 Title A Geometric Distance to the Small Magellanic Cloud using the Expanding Supernova Remnant 1E 0102-7219 ------------------------------------------------------------------------------------ Type Cycle GO 20 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Barry F. Madore Carnegie Institution of Washington Y CoI: Dr. Wendy L. Freedman Carnegie Institution of Washington N ------------------------------------------------------------------------------------ Abstract 1E 0102-7219 is a highly symmetric, rapidly expanding, supernova remnant in the the Small Magellanic Cloud. We propose to use 1E~0102 to independently derive a geometric distance to the SMC. Scaling the transverse proper motions to match the line-of-sight radial motions directly gives the distance. Previous studies have reported measuring stellar proper motions in the SMC of 1.1 +/- 0.2 mas/yr (a precision of about 17%) for transverse velocities of stars in the SMC of only 300 km/s within a time a baseline of only 2 years. Given that our expansion velocities (peak-to-peak) are around 6, 000 km/s (a factor of 20 larger) and that we will have a time baseline between ACS observations of at least 9 years (another factor of 4 larger) we estimate that our SNR proper motions will be measured to better than 1% precision. At this point assumptions in the modeling will dominate the systematics. 1E 0102 is one of the nearest extragalactic test cases for this method and it will be the archetype and testbed for investigating systematics and assessing the potential of this method for determining distances to additional galaxies at larger distances. We are simply requesting a single-orbit ACS observation using the F475W filter for comparison with an identical image taken 9 years ago. ------------------------------------------------------------------------------------ Observations Description ------------------------ Single-orbit image of SMC SNR in the oxygen line. To be used for a proper motion study and distance determination. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- This is a high-precsion proper motion study. Having the chip oriented north-south as closely the same as the first epoch observation would be very advantageous. The first-epoch observations were made with this same instrument on 2006-10-15. Reference: MAST Dataset = J8R802010 12858( 3) - 06-Nov-2012 13:33:02 - [ 2] ------------------------------------------------------------------------------------ 12858( 3) - 06-Nov-2012 13:33:02 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SMC-SNR-1E EXT-MEDIUM, SNR RA=01H04M1.5300S +/- 0.1", J2000 V = 18. +/- 1.0 DEC=-72D01'58.70" +/- 0.1" Reference Frame: ICRS Comments: This is a high-precsion proper motion study. Having the chip oriented as closely the same as the first epoch observation would be very advantageous. The first-epoch observations were made with this same instrument on 2006-10-15. Mast Dataset = J8R802010 September 24 through Nov 3, 2012 would allow for a 0 degree roll angle (N-S orientation) ------------------------------------------------------------------------------------------------------------------------------------ 12858( 3) - 06-Nov-2012 13:33:02 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-WFC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.265 Line_Spacing 0.187 Coordinate_Frame POS-TARG Pattern_Orient 20.67 Angle_Between_Sides 69.05 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 12858( 3) - 06-Nov-2012 13:33:02 - [ 5] Visit: 02 Visit Requirements: SCHED 100%; ORIENT 184.082306D TO 184.082306 D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SMC-SNR-1E ACS/WFC ACCUM WFC1-CTE F475W 1 511 S POS TARG -13, -5; PATTERN 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SMC-SNR-1E 1 ACS/WFC ACCUM WFC1-CTE F475W 1 none none none 1 N/A SMC-SNR-1E 1 ACS/WFC ACCUM WFC1-CTE F475W 2 none none none 1 N/A SMC-SNR-1E 1 ACS/WFC ACCUM WFC1-CTE F475W 3 none none none 1 N/A SMC-SNR-1E 1 ACS/WFC ACCUM WFC1-CTE F475W 4 none none none 1 N/A 12858( 3) - 06-Nov-2012 13:33:02 - [ 6] Summary Form for Proposal 12858 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC1-CTE ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 184.082306D TO 184.082306 D, PATTERN 1 1, POS TARG -13, -5, SCHED 100% ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F475W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SMC-SNR-1E ------------------------------------------------------------------------------------------------------------------------------------