Optical Discovery of New and Candidate Galactic Supernova Remnants Plus Optical Imaging of the Monogem Supernova Remnant

@misc{fesen2026optical,
  title = {{Optical Discovery of New and Candidate Galactic Supernova Remnants Plus Optical Imaging of the Monogem Supernova Remnant}},
  author = {Robert A. Fesen and Marcel Drechsler and Bray Falls and Tim Schaeffer and Justin Anderson and Deepanshu Arora and Werner Becker and Carl Bjork and Steeve Body and Laurent Huet and Tarun Kottary and Mathew Ludgate and Nicolas Martino and Manuel Peitsch and Wolfgang Reich and Jose Rodrigues and Yann Sainty and Patrick Sparkman and Sean Walker},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2608.26666},
  eprint = {2608.26666},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2608.26666},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Optical Discovery of New and Candidate Galactic Supernova Remnants Plus Optical Imaging of the Monogem Supernova Remnant
AU  - Robert A. Fesen
AU  - Marcel Drechsler
AU  - Bray Falls
AU  - Tim Schaeffer
AU  - Justin Anderson
AU  - Deepanshu Arora
AU  - Werner Becker
AU  - Carl Bjork
AU  - Steeve Body
AU  - Laurent Huet
AU  - Tarun Kottary
AU  - Mathew Ludgate
AU  - Nicolas Martino
AU  - Manuel Peitsch
AU  - Wolfgang Reich
AU  - Jose Rodrigues
AU  - Yann Sainty
AU  - Patrick Sparkman
AU  - Sean Walker
PY  - 2026
DA  - 2026/09/07
PB  - arXiv
DO  - 10.48550/arxiv.2608.26666
UR  - https://arxiv.org/abs/2608.26666
AB  - We report the discovery of new and candidate Galactic supernova remnants made through over 2000 hours of Hα and [O III] imaging using amateur class instrumentation. These nebulae range from 0.5 to over 8 degrees in size. Five of these, namely G27.8-17.1, G115.6+9.2, G190.5+25.3, G195.9+2.2 and G239.9+7.0 exhibit low-dispersion optical spectra indicating shock emission by the presence of strong [S II] λλ6716,6731 and [O I] λ6300 line emissions relative to Hα, or exhibit a nonradiative shock generated Balmer dominated spectrum. Their filamentary emission morphology also supports the presence of interstellar shock fronts. Three other optical nebulae, G191.3+11.1, G205.7-1.7, and G305.4-0.7 appear likely to be remnants and are proposed as new SNR candidates. We also present [O III] and Hα images of optical filaments associated with the 25 degree diameter Monogem Ring SNR which reveal extensive emission-line filaments around most of the remnant's X-ray boundaries. Deep images of the X-ray suspected remnant G190.4+12.5 and the large and [O III] emission dominated SNR G206.6+6.1 seen toward or near the Monogem SNR are also included. Key findings of this work include: 1) optical surveys can sometimes detect SNRs better than radio and X-ray SNR searches, 2) Balmer nonradiative shocks appear not uncommon in high Galactic latitude SNRs, and 3) faint \O3 emission dominated SNRs may have been missed in prior Hα emission only surveys.
ER  -