* Astronomy

Members Login
Username 
 
Password 
    Remember Me  
Post Info TOPIC: Supernova 1986J


L

Posts: 131433
Date:
Supernova 1986J
Permalink  
 


Title: SN 1986J VLBI. III. The Central Component Becomes Dominant
Author: Michael F. Bietenholz, Norbert Bartel

We present a new 5-GHz global-VLBI image of supernova 1986J, observed in 2014 at t = 31.6 yr after the explosion, and compare it to previous images to show the evolution of the supernova. Our new image has a dynamic range of ~100 and a background rms noise level of 5.9 microJy/beam. There is no significant linear polarization, with the image peak being <3% polarized. The latest image is dominated by the compact central component, whose flux density is now comparable to that of the extended supernova shell. This central component is marginally resolved with a FWHM width of 900 (-500,+100) micro-arcsec, corresponding to a radius of r_comp = 6.7 (-3.7,+0.7) * 10^{16} cm for a distance of 10 Mpc. Using VLBI observations between 2002 and 2014, we measured the proper motions of both the central component and a hot-spot to the NE in the shell relative to the quasar 3C~66A. The central component is stationary to within the uncertainty of 12 micor-arcsec/yr, corresponding to 570 km/s. Our observations argue in favour of the central component being located near the physical center of SN 1986J. The shell hot-spot had a mean velocity of 2700 810 km/s to the NE, which is consistent with it taking part in the homologous expansion of the shell seen earlier. The shell emission is evolving in a non-selfsimilar fashion, with the brightest emission shifting inwards within the structure, and with only relatively faint emission being seen near the outer edge and presumed forward shock.

Read more (299kb, PDF)

Ed ~ Supernova 1986J was hosted in NGC 891



__________________
Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard