3D Optical Spectroscopic Study of NGC3344 with SITELLE: I.
  Identification and Confirmation of Supernova Remnants
  We present the first optical identification and confirmation of a sample of
supernova remnants (SNRs) in the nearby galaxy NGC3344. Using high spectral and
spatial resolution data, obtained with the CFHT imaging Fourier transform
spectrograph SITELLE, we identified about 2200 emission line regions, many of
which are HII regions, diffuse ionized gas regions, and also SNRs. Considering
the stellar population and diffuse ionized gas background, that are quite
important in NGC3344, we have selected 129 SNR candidates based on four
criteria for regions where the emission lines flux ratio [S
II]/H$\alpha$$\ge$0.4. Emission lines of [O II]$\lambda$3727, H$\alpha$, [O
III]$\lambda\lambda$4959,5007, H$\alpha$, [N II]$\lambda\lambda$6548,6583, and
[S II]$\lambda\lambda$6716,6731 have been measured to study the ionized gas
properties of the SNR candidates. We adopted a self-consistent spectroscopic
analysis, based on Sabbadin plots and BPT diagrams, to confirm the shock-heated
nature of the ionization mechanism in the candidates sample. With this
analysis, we end up with 42 Confirmed SNRs, 45 Probable SNRs, and 42 Less
likely SNRs. Using shock models, the Confirmed SNRs seems to have a metallicity
ranging between LMC and 2$\times$solar. We looked for correlations between the
size of the Confirmed SNRs and their emission lines ratios, their galaxy
environment, and their galactocentric distance: we see a trend for a
metallicity gradient among the SNR population, along with some evolutionary
effects.
