First detection of optical light from SNR G279.0+1.1
  This is the initial paper in a series presenting the first optical detections
and subsequent follow-up spectroscopy of known Southern Galactic supernova
remnants (SNRs) previously discovered in the radio. These new detections come
from the AAO/UKST HAlpha survey of the Southern Galactic plane which has opened
up fresh opportunities to study Galactic remnants. Here we present the first
optical imaging and follow-up spectra of Galactic SNR G279.0+1.1 where a series
of 14 small-scale fragmented groups of HAlpha filaments have been discovered in
a ~2.3 deg. area centred on G279.0+1.1. Individually they are somewhat
inconspicuous but collectively they are completely enclosed within the overall
radio contours of this known SNR. Three of these filamentary groupings are
particularly prominent and optical spectra have been obtained across two of
them. Their morphological structure and spectral characteristics are typical of
optically detected SNR filaments. Very strong [S II] emission relative to H has
been detected with [S II]/HAlpha 0.7 and 1.1, confirming strong, shock heated
emission. This is sufficient to classify these filaments in the likely SNR
domain and therefore indicating a direct connection with the radio remnant.
Other typical SNR emission lines such as [O II] at 3727A, HBeta, [O III] at
4959 and 5007A, HAlpha and [N II] at 6548 and 6584A were also detected, lending
strong support to an SNR origin of these optical filaments. The value and
insights that these optical data can provide for known remnants are discussed
along with their relevance to the Galactic nitrogen abundance. A serendipitous
discovery of an adjacent H II region is also briefly described.
