DISCOVERY OF AN APPARENT HIGH LATITUDE GALACTIC SUPERNOVA REMNANT

作者：Fesen Robert A^*; Neustadt Jack M M; Black Christine S; Koeppel Ari H D

来源：Astrophysical Journal, 2015, 812(1): 37.

DOI：10.1088/0004-637X/812/1/37

• ISM: individual objects (G70.0-21.5)
• ISM: supernova remnants
• shock waves
• techniques: spectroscopic
• X-rays: ISM

Deep Ha images of a faint emission complex 4 degrees 0 x 5 degrees 5 in angular extent and located far off the Galactic plane at l = 70 degrees 0, b = -21 degrees 5 reveal numerous thin filaments suggestive of a supernova remnant's (SNR's) shock emission. Low dispersion optical spectra covering the wavelength range 4500-7500 angstrom show only Balmer line emissions for one filament while three others show a Balmer dominated spectrum along with weak [N I] 5198, 5200 angstrom, [O I] 6300, 6364 angstrom, [N II] 6583 angstrom, [S II] 6716, 6731 angstrom, and in one case [O III] 5007 angstrom line emision. Many of the brighter Ha filaments are visible in near-UV GALEX images presumably due to C III] 1909 angstrom line emission. ROSAT All Sky Survey images of this region show a faint crescent-shaped X-ray emission nebula coincident with the portion of the Ha nebulosity closest to the Galactic plane. The presence of long, thin Balmer dominated emission filaments with associated UV emission and coincident X-ray emission suggests this nebula is a high latitude Galactic SNR despite a lack of known associated nonthermal radio emission. Relative line intensities of the optical lines in some filaments differ from commonly observed [S II]/H alpha >= 0.4 radiative shocked filaments and typical Balmer filaments in SNRs. We discuss possible causes for the unusual optical SNR spectra.

• 出版日期2015-10-10