Please find attached our submission of "The proper motion of SGR 0501+4516" for Cycle 18 GO.Assigned ID: 560
----- Attempting Submission 1 (Fri Feb 26 20:06:30 GMT 2010) -----Please find attached our phaseII for 12306. We have asked for an observation early in Cycle 18 (in our phaseI) but as precise
visibility etc was not known did not have a single data. Based on the visit planner we have asked for observations before the
end of the October 2010 window - earlier would be fine.
We have also added some roll angle constraints to avoid diffraction spikes from bright stars. I would be very grateful if
somebody could look at these and check if they seem excessive (or indeed not enough). The aim has been to avoid both
fainter diffraction spikes from nearby stars (H~14-16) and brighter spikes from more distant stars (H=9.5-12).----- Attempting Submission 1 (Fri Jul 09 16:53:20 GMT 2010) -----The proper motion of SGR 0501+4516We 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.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 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.HOT STARS12false0.00.0falsefalsefalsefalsefalsefalseSUPPORTEDSTARNEUTRON STARK=20.2J200005 01 6.7500+45 16 34.00J2000WFC3/IRImagingNoNoF160WWFC3/IRImagingNoNoF160WPOS-TARGDITHER1.716LINE1.095falsefalse74.653418.528WFC3-IR-DITHER-BOX-MIN1falseThe scheduling data was generated by CASM 18.3.1.CASM was run in Phase II mode./private/var/folders/dw/dw1O6cyEGAmmPy90Qd-X6U+++TQ/-Tmp-/OPVisit3527160175047584297.xml(Tic-Visit
:proposal-id 12306
:visit-id "01"
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:trans-version "20100505"
:date "09-Jul-2010 17:51:34.0"
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