http://bear.ras.ucalgary.ca/brads_home_page/myresearch.html (Einblicke ins Internet, 10/1995)
What you see above is the supernova remnant (SNR) G59.5+0.1 (upper middle, the roughly round nebula) and the Sharpless HII region S87 (the elongated nebula to the lower left). The "bulls-eye" feature to the right of the SNR is an artifact. Ignore it.
The SNR G59.5+0.1 was discovered in a low frequency survey of the galactic plane, has the following physical characteristics. These may differ from the values in Dave Green's master SNR list. Where there are differences you may assume that my values are correct (or, at least, up to date).
The SNR is at the same distance as the HII region. This can be said because there is evidence of interaction between the SNR and the HII region in HI and CO data. Using a flat galactic rotation curve puts this system at either 3 or 6 kpc from the solar system (the distance ambiguity is due to the double valued nature of the galactic rotation curve for the inner galaxy). The fact that this object is optically visible (even though it is in the plane of the galaxy) argues for the lesser distance. This suggests that the SNR has a physical size of roughly 16 pc.
The SNR G63.7+1.1 (above) is a filled-center SNR similar to the Crab Nebula, also discovered in low frequency survey of the galactic plane. This means that it has an amorphous radio continuum morphology without any indication of a surrounding shell. My thesis research concerns investigating the ISM around this type of SNR to see if the lack of a radio continuum shell is due to the medium in which the SNR lies ("nurture"), or if it is instead due to these type of SNRs being fundamentally different than other types of SNRs ("nature").
It is in this context that I am interested in G63.7+1.1. HI data for the region around the SNR (obtained with the Dominion Radio Astrophysical Observatory) suggests that the SNR may be interacting directly with the ISM (as opposed to interacting via an invisible shell of material around the SNR). This may argue for the "nature" explanation for the abscence of a shell, as opposed to the "nurture" explanation.
This object, the most famous of SNRs, is also an object of my attention. Low resolution HI observations of the region around the Crab Nebula (as well as two other filled-center SNRs, see our paper on this subject) suggest that filled-center SNRs may lie in regions of the ISM having lower than "normal" densities. This suggests that if these objects are surrounded by "halos" of high velocity material, that this material may be invisible due to the lack of any interaction between the "halo" of material and the ISM. I have a number of observations in the works to investigate the ISM around the Crab Nebula to help answer this question. (The image of the Crab Nebula above was taken by Bill Keel.)