Far UV and Optical Emissions from Three Very Large Supernova Remnants Located at Unusually High Galactic Latitudes

Abstract

Galactic supernova remnants (SNRs) with angular dimensions greater than a few degrees are relatively rare, as are remnants located more than ten degrees off the Galactic plane. Here we report a UV and optical investigation of two previously suspected SNRs more than ten degrees in both angular diameter and Galactic latitude. One is a proposed remnant discovered in 2008 through 1420 MHz polarization maps near Galactic coordinates $l$ = 353, $b$ = $-$34. GALEX far UV (FUV) and H$\alpha$ emission mosaics show the object's radio emission coincident with a 11 x 14 degree shell of UV filaments surrounding a diffuse H$\alpha$ emission ring. Another proposed high latitude SNR is the 20 x 26 degree Antlia nebula (G275.5+18.4) discovered in 2002 through low-resolution all-sky H$\alpha$ and ROSAT soft X-ray emissions. GALEX UV and H$\alpha$ mosaics along with optical spectra indicate the presence of shocks throughout the Antlia nebula with estimated shock velocities of 70 to over 100 km s${}^{-1}$. We also present evidence that it has collided with the northeast rim of the Gum Nebula. We find both of these nebulae are bona fide SNRs with ages less than 10${}^5$ yr despite their unusually large angular dimensions. We also present FUV and optical images along with optical spectra of a new high-latitude SNR (G249.7+24.7) some 4.5 degrees in diameter which has also been independently discovered in X-rays and radio (Becker at al. 2021). We find this remnant's distance to be $\le$400 pc based on the detection of red and blue shifted Na I absorption features in the spectra of two background stars.

arXiv comment32 pages, 21 figures, 4 tables; Revised to match published version in the Astrophysical Journal

References in corpus (45)

• Cosmic-Ray Rejection by Laplacian Edge Detection
• A Full-Sky H-alpha Template for Microwave Foreground Prediction
• A Robotic Wide-Angle H-Alpha Survey of the Southern Sky
• A Census of High-Energy Observations of Galactic Supernova Remnants
• A revised catalogue of 294 Galactic supernova remnants
• Detection of large-scale X-ray bubbles in the Milky Way halo
• Effects of Pre-ionisation in Radiative Shocks I: Self-Consistent Models
• Constraints on the distribution of supernova remnants with Galactocentric radius
• New Galactic supernova remnants discovered with IPHAS
• The SPEAR Instrument and On-Orbit Performance
• A radio-polarisation and rotation measure study of the Gum Nebula and its environment
• A diagnostic tool for the identification of Supernova Remnants
• A multi-wavelength study of Supernova Remnants in six nearby galaxies. II. New optically selected Supernova Remnants
• Galactic interstellar turbulence in the southern sky seen through spatial gradients of the polarization vector
• Far Ultraviolet Spectra of a Non-Radiative Shock Wave in the Cygnus Loop
• The Cygnus Loop's Distance, Properties, and Environment Driven Morphology
• Newly confirmed and high quality candidate Galactic SNRs uncovered from the AAO/UKST HAlpha survey
• Spectroscopy and Time Variability of Absorption Lines in the Direction of the Vela Supernova Remnant
• A radio continuum survey of the southern sky at 1420 MHz. Observations and data reduction
• Four new X-ray-selected supernova remnants in the Large Magellanic Cloud
• Discovery of an Apparent High Latitude Galactic Supernova Remnant
• Multi-wavelength study of a new Galactic SNR G332.5-5.6
• Catalogue of known Galactic SNRs uncovered in HAalpa light
• Discovery of optical emission from the supernova remnant G 32.8-0.1 (Kes 78)
• Hoinga: A supernova remnant discovered in the SRG/eROSITA All-Sky Survey eRASS1
• Far-UV Observations of a Thermal Interface in the Orion-Eridanus Superbubble
• Investigating Galactic supernova remnant candidates with LOFAR
• G107.0+9.0: A New Large Optically Bright, Radio and X-Ray Faint Galactic Supernova Remnant in Cepheus
• SPEAR Far Ultraviolet Spectral Images of the Cygnus Loop
• The Neutron Star Born in the Antlia Supernova Remnant
• HST-STIS Observations of the Cygnus Loop: Spatial Structure of a Non-radiative Shock
• Far Ultraviolet Spectral Images of the Vela Supernova Remnant
• New optical filamentary structures in Pegasus
• Intermediate-velocity gas observed towards the Shajn 147 SNR
• The distance, rotation, and physical parameters of zeta Pup
• Discovery of a Thirty-Degree Long Ultraviolet Arc in Ursa Major
• Low Mass Star Formation in the Gum Nebula: The CG~30/31/38 complex
• A Straight and Narrow Ionized Filament
• Optical detection and spectroscopic confirmation of supernova remnant G213.0-0.6 (now re-designated as G213.3-0.4)
• Optical Emission Associated with the Galactic Supernova Remnant G179.0+2.6
• Far-Ultraviolet Cooling Features of the Antlia Supernova Remnant
• Diffuse Far-ultraviolet Observation of the Lupus Loop Region
• Detection of Extensive Optical Emission from the Extremely Radio Faint Galactic Supernova Remnant G182.4+4.3
• Confirmation of G6.31+0.54 as a part of a Galactic supernova remnant
• High-velocity interstellar absorption associated with the supernova remnant W28

Cited by in corpus (14)

• A candidate runaway supermassive black hole identified by shocks and star formation in its wake
• Are pulsar halos rare ?
• The SRG/eROSITA diffuse soft X-ray background. I. The local hot bubble in the western Galactic hemisphere
• Deep optical study of the mixed-morphology supernova remnant G 132.7+1.3 (HB3)
• The Far Ultraviolet Background
• First optical identification of the SRG/eROSITA-detected supernova remnant G 116.6-26.1 I. Preliminary results
• Odd Radio Circles as supernovae remnants in the intragroup medium
• Discovery of a filamentary synchrotron structure connected to the coherent magnetic field in the outer Galaxy
• Extended far-UV emission surrounding asymptotic giant branch stars as seen by GALEX
• Multi-wavelength study of the high Galactic latitude supernova remnant candidate G118.4+37.0 associated with the Calvera pulsar
• A Census of Pulsars in Possible Association with Galactic Open Clusters
• Research Programs Arising from 'Oumuamua Considered as an Alien Craft
• New X-ray Supernova Remnants in NGC 7793
• Observations of ionized carbon towards the $\gamma$-ray-bright supernova remnant RX J1713.7-3946