Deep Hα images of a faint emission complex 4.0 x 5.5 degrees in
angular extent and located far off the Galactic plane at l = 70.0 degrees,
b=-21.5 degrees reveal numerous thin filaments suggestive of a supernova
remnant's shock emission. Low dispersion optical spectra covering the
wavelength range 4500 - 7500 A show only Balmer line emissions for one filament
while three others show a Balmer dominated spectrum along with weak [N I] 5198,
5200 A, [O I] 6300, 6364 A, [N II] 6583 A, [S II] 6716, 6731 A and in one case
[O III] 5007 A line emission. Many of the brighter Hα filaments are
visible in near UV GALEX images presumably due to C III] 1909 A 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 Hα 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 supernova remnant 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]/Hα
> 0.4 radiative shocked filaments and typical Balmer filaments in supernova
remnants. We discuss possible causes for the unusual optical SNR spectra.Comment: 12 pages, 10 figures, accepted to the Astrophysical Journa
