TY - JOUR
T1 - Proper motions of Hα filaments in the supernova remnant RCW 86
AU - Helder, E. A.
AU - Vink, J.
AU - Bamba, A.
AU - Bleeker, J. A.M.
AU - Burrows, D. N.
AU - Ghavamian, P.
AU - Yamazaki, R.
PY - 2013/10
Y1 - 2013/10
N2 - We present a proper motion study of the eastern shock-region of the supernova remnant RCW 86 (MSH 14-63, G315.4-2.3), based on optical observations carried out with Very Large Telescope/FOcal Reducer and low dispersion Spectrograph 2 in 2007 and 2010. For both the north-eastern and south-eastern regions, wemeasure an average proper motion of Ha filaments of 0.10±0.02 arcsec yr-1, corresponding to 1200±200 km s-1 at 2.5 kpc. There is substantial variation in the derived proper motions, indicating shock velocities ranging from just below 700 km s-1 to above 2200 km s-1. The optical proper motion is lower than the previously measured X-ray proper motion of north-eastern region. The new measurements are consistent with the previously measured proton temperature of 2.3 ± 0.3 keV, assuming no cosmic ray acceleration. However, within the uncertainties, moderately efficient (<27 per cent) shock acceleration is still possible. The combination of optical proper motion and proton temperature rule out the possibility thatRCW 86 has a distance less than 1.5 kpc. The similarity of the proper motions in the north-eastand south-east is peculiar, given the different densities and X-ray emission properties of the regions. The north-eastern region has lower densities and the X-ray emission is synchrotron dominated, suggesting that the shock velocities should be higher than in the south-eastern, thermal X-ray dominated, region. A possible solution is that the Ha emitting filaments are biased towards denser regions, with lower shock velocities. Alternatively, in the north-east the shock velocity may have decreased rapidly during the past 200 yr, and the X-ray synchrotron emission is an afterglow from a period when the shock velocity was higher.
AB - We present a proper motion study of the eastern shock-region of the supernova remnant RCW 86 (MSH 14-63, G315.4-2.3), based on optical observations carried out with Very Large Telescope/FOcal Reducer and low dispersion Spectrograph 2 in 2007 and 2010. For both the north-eastern and south-eastern regions, wemeasure an average proper motion of Ha filaments of 0.10±0.02 arcsec yr-1, corresponding to 1200±200 km s-1 at 2.5 kpc. There is substantial variation in the derived proper motions, indicating shock velocities ranging from just below 700 km s-1 to above 2200 km s-1. The optical proper motion is lower than the previously measured X-ray proper motion of north-eastern region. The new measurements are consistent with the previously measured proton temperature of 2.3 ± 0.3 keV, assuming no cosmic ray acceleration. However, within the uncertainties, moderately efficient (<27 per cent) shock acceleration is still possible. The combination of optical proper motion and proton temperature rule out the possibility thatRCW 86 has a distance less than 1.5 kpc. The similarity of the proper motions in the north-eastand south-east is peculiar, given the different densities and X-ray emission properties of the regions. The north-eastern region has lower densities and the X-ray emission is synchrotron dominated, suggesting that the shock velocities should be higher than in the south-eastern, thermal X-ray dominated, region. A possible solution is that the Ha emitting filaments are biased towards denser regions, with lower shock velocities. Alternatively, in the north-east the shock velocity may have decreased rapidly during the past 200 yr, and the X-ray synchrotron emission is an afterglow from a period when the shock velocity was higher.
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U2 - 10.1093/mnras/stt993
DO - 10.1093/mnras/stt993
M3 - Article
AN - SCOPUS:84884769909
VL - 435
SP - 910
EP - 916
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 2
ER -