Affiliation:
1. University of Crete, Department of Physics, Voutes University Campus , GR-70013 Heraklion, Greece
2. Foundation for Research and Technology – Hellas , P.O. Box 1385, GR-71110 Heraklion, Greece
Abstract
ABSTRACT
The supernova remnant (SNR) candidate G 116.6 − 26.1 is one of the few high Galactic latitude (|b| > 15°) remnants detected so far in several wavebands. It was discovered recently in the SRG/eROSITA all-sky X-ray survey and also displays a low-frequency weak radio signature. In this study, we report the first optical detection of G 116.6 − 26.1 through deep, wide-field, and higher resolution narrowband imaging in H$\alpha$, $[\rm S\,{\small{\rm II}}]$ and $[\rm O\,{\small{\rm III}}]$ light. The object exhibits two major and distinct filamentary emission structures in a partial shell-like formation. The optical filaments are found in an excellent positional match with available X-ray, radio, and UV maps, can be traced over a relatively long angular distance (38 and 70 arcmin) and appear unaffected by any strong interactions with the ambient interstellar medium. We also present a flux-calibrated, optical emission spectrum from a single location, with Balmer and several forbidden lines detected, indicative of emission from shock excitation in a typical evolved SNR. Confirmation of the most likely SNR nature of G 116.6 − 26.1 is provided from the observed value of the line ratio [S ii] / H$\alpha$ = $0.56\, \pm \, 0.06$, which exceeds the widely accepted threshold 0.4, and is further strengthened by the positive outcome of several diagnostic tests for shock emission. Our results indicate an approximate shock velocity range 70–100 km s−1 at the spectroscopically examined filament, which, when combined with the low emissivity in H$\alpha$ and other emission lines, suggest that G 116.6 − 26.1 is a SNR at a mature evolutionary stage.
Funder
National Science Foundation
National Aeronautics and Space Administration
California Institute of Technology
University of California
European Research Council
Publisher
Oxford University Press (OUP)
Subject
Space and Planetary Science,Astronomy and Astrophysics
Cited by
2 articles.
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