A Near-Infrared Survey of the Inner Galactic Plane for Wolf-Rayet Stars III. New Methods: Most Distant Known Galactic WR Stars Graham C. Kanarek Columbia University, New York, NY Michael M. Shara American Museum of Natural History 79th Street and Central Park West, NewYork, NY, 10024-5192 Jacqueline K. Faherty Department of Terrestrial Magnetism, Carnegie Institution of Washington 5241 Broad Branch Road NW, Washington, DC 20015 David Zurek American Museum of Natural History 79th Street and Central Park West, NewYork, NY, 10024-5192 Anthony F.J. Moffat D´ epartment de Physique, Universit´ e de Montr´ eal CP 6128 Succ. C-V, Montr´ eal, QC, H3C 3J7, Canada ABSTRACT A new method of image subtraction is applied to images from a J, K, and narrow- band imaging survey of 300 square degrees of the plane of the Galaxy, searching for new Wolf-Rayet stars. Our survey spans 150 degrees in Galactic longitude and reaches 1 degree above and below the Galactic plane. The survey has a useful limiting magnitude of K = 15 over most of the observed Galactic plane, and K = 14 (due to severe crowd- ing) within a few degrees of the Galactic center. The new image subtraction methods (better than aperture or even point-spread-function photometry in very crowded fields) detected several thousand emission-line candidates. In June and July 2011 and 2012, we spectroscopically followed up on 333 candidates with MDM-TIFKAM and IRTF-SPEX, discovering 90 new emission-line sources. These include 55 new Wolf-Rayet stars, com- prising the most distant known Galactic WR stars, more than doubling the number on the far side of the Milky Way. We also demonstrate our survey’s ability to detect very distant PNe and other NIR emission objects. arXiv:1403.0975v1 [astro-ph.SR] 4 Mar 2014