Far-UV and Optical Emissions from Three Very Large Supernova Remnants Located at Unusually High Galactic Latitudes
| Autor: | Bhagya M. Subrayan, Robert A. Fesen, Xavier Strottner, Marcel Drechsler, Dennis di Cicco, Kathryn E. Weil, John C. Raymond, David Mittelman, Sean Walker, Mathew Ludgate, Dan Milisavljevic, Justin D. Rupert |
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| Rok vydání: | 2021 |
| Předmět: |
High Energy Astrophysical Phenomena (astro-ph.HE)
Physics Nebula Astrophysics::High Energy Astrophysical Phenomena Gum Nebula FOS: Physical sciences Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Galactic plane Stars Supernova Space and Planetary Science Angular diameter ROSAT Astrophysics::Solar and Stellar Astrophysics Galactic coordinate system Astrophysics - High Energy Astrophysical Phenomena Astrophysics::Galaxy Astrophysics |
| Zdroj: | The Astrophysical Journal. 920:90 |
| ISSN: | 1538-4357 0004-637X |
| Popis: | 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 $\leq$400 pc based on the detection of red and blue shifted Na I absorption features in the spectra of two background stars. Comment: 32 pages, 21 figures, 4 tables; Revised to match published version in the Astrophysical Journal |
| Databáze: | OpenAIRE |
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