12672( 3) - 01-Jul-2011 18:05:44 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 12672 Version: 3 Check-in Time: 01-Jul-2011 18:05:44 STScI Edit Number: 0 Title The proper motion of SGR 0501+4516 ------------------------------------------------------------------------------------ Type Cycle GO 19 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Andrew J. Levan The University of Warwick CoI: Prof. Nial R. Tanvir University of Leicester N CoI: Dr. C. Kouveliotou NASA Marshall Space Flight Center N CoI: Dr. Danny Steeghs The University of Warwick N CoI: Prof. Thomas R. Marsh The University of Warwick N CoI: Dr. Evert Rol University of Leicester N CoI: Dr. Klaas Wiersema University of Leicester N CoI: Dr. Vik Dhillon University of Sheffield N CoI: Dr. Nanda Rea INAF, Osservatorio Astronomico di Roma N ------------------------------------------------------------------------------------ Abstract We propose to obtain two epochs of WFC3/IR imaging of the counterpart of the soft gamma-repeater, SGR 0501+4516 to measure its proper motion and hence identify its birth place and constrain its age in a model independent manner. Our ground based observations have already located the optical/IR counterpart, and provided proper motion limits of <70 mas/yr. The source has now faded significantly since its first discovery and is becoming too faint for detailed ground based study. Using the excellent point spread function, wide field of view, astrometric stability, and sensitivity of WFC3, we can now make use of HST to directly measure the proper motion of an SGR for the first time. The location of SGR 0501+4516 in the Galactic anti-centre direction, with a likely low distance (~1.5 kpc), coupled with moderate foreground extinction, and no issues of crowding makes it the only SGR source for which such observations are plausible with current technology. Our proposed observations (one in Cycle 18 and one in Cycle 19) with a baseline of ~2 years should constrain the proper motion to better than 3-4 milliarcseconds per year (3 sigma), corresponding to spatial velocities of less than 25 km/s, smaller than the velocities observed for many radio pulsars. Hence we can place the first direct constraints on the kick velocities given to magnetars at their birth, as well as testing models for their age and evolution, and informing estimates of their rate of creation. ------------------------------------------------------------------------------------ Observations Description ------------------------ We propose to obtain a proper motion for SGR 0501+4516 via two epochs of observations. One will be taken early in Cycle 18, with a second visit to follow towards the end of Cycle 19, providing a time baseline of ~2 years. We will use the WFC3 IR channel and the F160W observations. We will use a 4 point dither pattern, but have multiplied the standard offsets by a factor of 3 to enable bright stars (which may leave persistence) to be well removed from eachother and hence possible to centroid with accuracy. Additionally we have 12672( 3) - 01-Jul-2011 18:05:44 - [ 2] specified a restricted range of roll angles, such that diffraction spikes from a bright object in the field at large angular spearation, and from fainter, but closer, objects will not overlap our target position. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 12672( 3) - 01-Jul-2011 18:05:44 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SGR0501+4516 STAR, NEUTRON STAR RA=05H01M6.7500S +/- 0.1", J2000 V = 27 +/- 1 K=20.2 DEC=+45D16'34.00" +/- 0.1" Reference Frame: Other: Gemini ------------------------------------------------------------------------------------------------------------------------------------ 12672( 3) - 01-Jul-2011 18:05:44 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-BOX-MIN Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 1.716 Line_Spacing 1.095 Coordinate_Frame POS-TARG Pattern_Orient 18.528 Angle_Between_Sides 74.653 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 12672( 3) - 01-Jul-2011 18:05:44 - [ 5] Visit: 01 Visit Requirements: ORIENT 0.0D TO 10.0 D; ORIENT 31D TO 47 D; ORIENT 53D TO 72 D; ORIENT 75D TO 100 D; ORIENT 121D TO 137 D; ORIENT 143D TO 162 D; ORIENT 165D TO 190 D; ORIENT 212D TO 226 D; ORIENT 232D TO 252 D; ORIENT 256D TO 280 D; ORIENT 301D TO 317 D; ORIENT 322D TO 341 D; ORIENT 346D TO 359.9 D; AFTER 31-JUL-2012:00:00:00 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 SGR0501+451 WFC3/IR MULTIAC IR F160W NSAMP=13, SAMP-SEQ=STEP100 1 DEF PATTERN 1 1 6 CUM ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SGR0501+4516 1 WFC3/IR MULTIAC IR F160W 1 none none none 1 N/A CUM SGR0501+4516 1 WFC3/IR MULTIAC IR F160W 2 none none none 1 N/A CUM SGR0501+4516 1 WFC3/IR MULTIAC IR F160W 3 none none none 1 N/A CUM SGR0501+4516 1 WFC3/IR MULTIAC IR F160W 4 none none none 1 N/A CUM 12672( 3) - 01-Jul-2011 18:05:44 - [ 6] Summary Form for Proposal 12672 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=13, SAMP-SEQ=STEP100 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 31-JUL-2012:00:00:00, ORIENT 0.0D TO 10.0 D, ORIENT 121D TO 137 D, ORIENT 143D TO 162 D, ORIENT 165D TO 190 D, ORIENT 212D TO 226 D, ORIENT 232D TO 252 D, ORIENT 256D TO 280 D, ORIENT 301D TO 317 D, ORIENT 31D TO 47 D, ORIENT 322D TO 341 D, ORIENT 346D TO 359.9 D, ORIENT 53D TO 72 D, ORIENT 75D TO 100 D, PATTERN 1 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F160W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SGR0501+4516 ------------------------------------------------------------------------------------------------------------------------------------