Optical detection and spectroscopic confirmation of supernova remnant G213.0−0.6 (now redesignated as G213.3−0.4)

Abstract

During a detailed search for optical counterparts of known Galactic supernova remnants (SNRs) using the Anglo‐Australian Observatory/United Kingdom Schmidt Telescope (AAO/UKST) Hα survey of the southern Galactic plane we have found characteristic optical Hα filaments and associated emission in the area of SNR G213.0−0.6. Although this remnant was previously detected in the radio as a non‐thermal source, we also confirm emission at 4850 MHz in the Parkes‐MIT‐NRAO (PMN) survey and at 1400 MHz in the NRAO/VLA Sky Survey (NVSS). There is an excellent match in morphological structure between the optical (Hα) and radio emission. We subsequently obtained optical spectroscopy of selected Hα filaments using the South African Astronomical Observatory 1.9‐m telescope which confirmed shock excitation typical of supernova remnants. Our discovery of Hα emission and the positional match with several radio frequency maps led us to reassign G213.0−0.6 as G213.3−0.4 as these coordinates more accurately reflect the actual centre of the SNR shell and hence the most probable place of the original supernova explosion. Support for this new SNR ID comes from the fact that the X‐ray source 1RXS J065049.7−003220 is situated in the centre of this new remnant and could be connected with the supernova explosion.

Molecular Environments of Three Large Supernova Remnants in the Third Galactic Quadrant: G205.5+0.5, G206.9+2.3, and G213.0–0.6

“…This result suggests that SNR G213.0−0.6 is interacting with a clumpy interstellar medium, which agrees with the CO emission near the Hα peak using our CO data (Figure 16). Assuming a constant value of X CO = 2 × 10 20 cm −2 K −1 km −1 s (Bolatto et al 2013), the MC's thickness of 4 ′ , and a distance of 1 kpc (see below), the density of the MC is about 300d −1 1kpc cm −3 , which is consistent with the result of the optical study (Stupar & Parker 2012). The interesting MC, as well as its velocity structure, suggests that the molecular gas with LSR velocity ∼8-11 km s −1 is probably interacting with SNR G213.0−0.6.…”

“…We suggest that this feature is probably related to the remnant's shock. Stupar & Parker (2012) found that the density in the region of the Hα peak is relatively high based on optical observations (n e ∼ 10 2 cm −3 , refer to Table 2 in their paper). This result suggests that SNR G213.0−0.6 is interacting with a clumpy interstellar medium, which agrees with the CO emission near the Hα peak using our CO data (Figure 16).…”

“…On the other hand, a large complex of H ii region Sh 2-284, which has bright optical, infrared, and radio emission, is located to the southwestern boundary of the remnant. The remnant was also named as G213.3−0.4 according to the new optical Hα imaging and relatively high-resolution radio observations from the PMN survey at 4.85 GHz and NRAO/VLA Sky Survey (NVSS) at 1.4 GHz (Stupar & Parker 2012). Following Green's SNR catalog (Green 2014), we use SNR G213.0−0.6 as its name throughout this paper.…”

The First Fermi Lat Supernova Remnant Catalog

“…The nearby TeV source HESS J1858+020 (Aharonian et al 2008c) has been proposed as originating from CRs escaping from the SNR and illuminating nearby clouds (Paron & Giacani 2010). SNR G213.3−0.4: a very low radio surface brightness SNR initially designated as G213.0−0.6 by Reich et al (2003), the SNR identification was later confirmed by optical line observations (Stupar & Parker 2012). The SNR lies near the H II region S284, which is coincident with the γ-ray source 2FGL J0647.7+0032.…”

Multifrequency study of a new Fe-rich supernova remnant in the Large Magellanic Cloud, MCSNR J0508−6902

“…It is a commonly adopted diagnostic (see Fesen et al 1985) that an [SII]/Hα ratio >0.5 can separate SNRs from planetary nebula and HII regions as seen and expected in SNRs (e.g Stupar & Parker 2012). It is clear from Table 1 that the observed [SII]/Hα ratio which ranges from 0.6 to 1.29, is strongly in the shocked regime for all fibres, particu- larly for 2dF fibres 260 and 259 which also happen to be on opposing sides of the optical shell.…”