The VMC survey. II. A multi-wavelength study of LMC planetary nebulae and their mimics

The VISTA Magellanic Cloud (VMC) survey is assembling a deep, multi-epoch atlas of YJK_s photometry across the Magellanic Clouds. Prior to the VMC survey only the brightest Magellanic Cloud PNe (MCPNe) were accessible at near-infrared (NIR) wavelengths. It is now possible for the first time to assemble the NIR properties of MCPNe and to identify contaminating non-PNe mimics which are best revealed at NIR wavelengths (e.g. HII regions and symbiotic stars). To maintain the unique scientific niche that MCPNe occupy these contaminants must be removed. Here we conduct a VMC-led, multi-wavelength study of 102 objects previously classified as PNe that are located within the first six VMC tiles observed. We present images, photometry, lightcurves, diagnostic colour - colour diagrams and spectral energy distributions used to analyse the entire sample. At least five PNe have newly resolved nebula morphologies, a task previously only possible with the HST. A total of 45/67 (67%) objects catalogued by Reid & Parker (RP) were reclassified as non-PNe, most of which were located in the vicinity of 30 Doradus. This sample included 16 field stars, 5 emission line stars, 19 HII regions, 4 symbiotic star candidates and 1 young stellar object. We discuss possible selection effects responsible for their inclusion in the RP catalogue and the implications for binary central star surveys targeting LMC PNe. A total of five new LMC symbiotic star candidates were identified, compared to eight previously known, underlining the important role the VMC survey will have in advancing Magellanic symbiotic star studies.

Based on observations made with VISTA at Paranal Observatory under program ID 179.B-2003 and the Wide Field Imager of the Max-Planck-ESO 2.2 m telescope at La Silla Observatory under programs 066.B-0553, 68.C-0019(A) and 076.C-0888.Appendices A and B are available in electronic form at http://www.aanda.org