A New Population of Planetary Nebulae Discovered in the Large Magellanic Cloud (II): Complete PN Catalogue

Abstract

This paper presents accurate homogeneous positions, velocities and other pertinent properties for 460 newly discovered and 169 previously known planetary nebulae (PNe) in the central 25 sq deg bar region of the Large Magellanic Cloud (LMC). Candidate emission sources were discovered using a deep, high resolution H-alpha map of the LMC obtained by median stacking a dozen 2 hour H-alpha exposures taken with the UK Schmidt Telescope (UKST). Our spectroscopic followup of more than 2,000 compact (ie. <20 arcsec) H-alpha emission candidates uncovered has tripled the number of PNe in this area. All of the 169 previously known PNe within this region have also been independently recovered and included in this paper to create a homogeneous data set. Of the newly discovered PNe, we classify 291 as &#34;true&#34;, 54 as &#34;likely&#34; and 115 as &#34;possible&#34; based on the strength of photometric and spectroscopic evidence. Radial velocities have been measured using both weighted averaging of emission lines and cross-correlation techniques against high quality templates. Based on the median comparison of the two systems, we define a measurement error of pm4 km/s. A new velocity map of the central 25 sq deg of the LMC, based on results from the combined new and previously known PNe, is presented, indicating an averaged heliocentric velocity differential of 65 km/s perpendicular to the line of nodes for the entire PN population across our survey area. Averaged velocities of our PNe and molecular hydrogen (from the literature) across 37 x 37 arcmin sub areas are compared.