SIMBAD references

2018ApJ...862..148H - Astrophys. J., 862, 148-148 (2018/August-1)

Constraints on cosmic-ray acceleration efficiency in Balmer shocks of two young Type Ia supernova remnants in the Large Magellanic Cloud.


Abstract (from CDS):

We present results from an optical study of two young Balmer-dominated remnants of SNIa in the Large Magellanic Cloud, 0509-67.5 and 0519-69.0, in an attempt to search for signatures of efficient cosmic-ray (CR) acceleration. We combine proper motion measurements with corresponding optical spectroscopic measurements of the Hα line at multiple rim positions from VLT/FORS2 and SALT/RSS and compare our results to published Balmer shock models. Analyses of the optical spectra result in broad Hα widths in the range of 1800-4000 km s–1 for 12 separate Balmer-dominated filaments that show no evidence for forbidden line emission; the corresponding shock speeds from proper motion measurements from HST span a range of 1700-8500 km s–1. Our measured values of shock speeds and broad Hα widths in 0509-67.5 and 0519-69.0 are fit well with a Balmer shock model that does not include effects of efficient CR acceleration. We determine an upper limit of 7%/χ (95% confidence) on the CR acceleration efficiency for our ensemble of data points, where χ is the ionization fraction of the pre-shock gas. The upper limits on the individual remnants are 6%/χ (0509-67.5) and 11%/χ (0519-69.0). These upper limits are below the integrated CR acceleration efficiency in the Tycho supernova remnant, where the shocks predominantly show little Hα emission, indicating that Balmer-dominated shocks are not efficient CR accelerators.

Abstract Copyright: © 2018. The American Astronomical Society. All rights reserved.

Journal keyword(s): cosmic rays - ISM: individual objects: SNR 0509-67.5, SNR 0519-69.0 - ISM: kinematics and dynamics - ISM: supernova remnants - shock waves

Simbad objects: 11

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