Planetary nebulae and supernova remnants in NGC 4214 from the SIGNALS survey

Abstract

Using datacubes from the imaging Fourier transform spectrometer SITELLE at the Canada-France-Hawaii Telescope as part of the star formation, ionized gas, and nebular abundances legacy survey, we identify 15 new planetary nebulae (PNe) as well as five new supernova remnants (SNRs) in the outer parts of the nearby dwarf starburst galaxy NGC 4214. These data also allow us to study the morphology and kinematics of all 18 known SNRs in this galaxy. We highlight the use of a $\xi = \sigma \frac{\rm {[S{\small \,II}]}}{\rm {H\alpha }}$ diagnostic diagram (σ being the velocity dispersion) to separate SNRs from H II regions and its advantage compared to classical BPT or Sabbadin diagrams. We provide the emission-line flux ([O III] λ5007, H α, and H β) and radial velocities of all new PNe candidates, as well as those of 12 of the 17 PNe previously discovered in the central part of the galaxy with Hubble Space Telescope (HST) data. Finally, we use the [O III] emission-line luminosity function of the PNe sample to establish a new velocity-independent distance for NGC 4214: $D = 3.23^{+0.18}_{-0.25}$ Mpc.