[vsnet-grb-info 6541] SGR 0501+4516: Proximity to supernova remnant HB9

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8149
SUBJECT: SGR 0501+4516: Proximity to supernova remnant HB9
DATE:    08/08/27 21:04:34 GMT
FROM:    Bryan Gaensler at U of Sydney  <bmg at physics.usyd.edu.au>

B. M. Gaensler (U. Sydney) and S. Chatterjee (U. Sydney) report:

We note that the newly identified magnetar SGR 0501+4516 
(GCN 8113) is in close proximity to the Galactic supernova 
remnant (SNR) HB9 = G160.9+2.6.

Specifically, the location of the SGR as determined by Swift XRT
(GCN 8112; GCN 8148) is just outside the south-eastern rim of HB9.
A 1.4 GHz radio image of the SNR taken from the Canadian Galactic
Plane Survey, and showing the position of the SGR, is available at:

http://www.physics.usyd.edu.au/~bmg/fig_sgr_snr.gif

The angular separation from the SNR's centre is approximately 
80 arcmin, corresponding to a projected space velocity of 
1700-4300 km/s for a distance to the SNR of 1.5 kpc and an age of
8000-20000 years (Leahy & Aschenbach, 1995, A&A, 293, 853).

The SGR's location outside the rim of a SNR and its high inferred
space velocity are similar properties to those inferred for other
SGRs. While there is as yet insufficient information to judge the
validity of a physical association between SGR 0501+4516 and SNR HB9, 
we note that this anti-centre region is relatively devoid of SNRs
and other evidence for massive star formation: there are only two
other catalogued SNRs within 15 degrees of this position.  A search
for other neutron stars associated with HB9 (Kaplan et al., 2006,
ApJS, 163, 344) did not detect any candidates.