J/AJ/148/137 Merging galaxies in COSMOS to z~1 (Lackner+, 2014) ================================================================================ Late-stage galaxy mergers in COSMOS to z~1. Lackner C.N., Silverman J.D., Salvato M., Kampczyk P., Kartaltepe J.S., Sanders D., Capak P., Civano F., Halliday C., Ilbert O., Jahnke K., Koekemoer A.M., Lee N., Le Fevre O., Liu C.T., Scoville N., Sheth K., Toft S. =2014AJ....148..137L ================================================================================ ADC_Keywords: Active gal. nuclei ; X-ray sources ; Redshifts ; Stars, masses ; Photometry, HST Keywords: galaxies: active - galaxies: formation - galaxies: interactions - techniques: image processing Abstract: The role of major mergers in galaxy and black hole formation is not well-constrained. To help address this, we develop an automated method to identify late-stage galaxy mergers before coalescence of the galactic cores. The resulting sample of mergers is distinct from those obtained using pair-finding and morphological indicators. Our method relies on median-filtering of high-resolution images to distinguish two concentrated galaxy nuclei at small separations. This method does not rely on low surface brightness features to identify mergers, and is therefore reliable to high redshift. Using mock images, we derive statistical contamination and incompleteness corrections for the fraction of late-stage mergers. The mock images show that our method returns an uncontaminated (<10%) sample of mergers with projected separations between 2.2 and 8kpc out to z~1. We apply our new method to a magnitude-limited (m_FW814_<23) sample of 44164 galaxies from the COSMOS HST/ACS catalog. Using a mass-complete sample with log M_{star}_/M_{sun}_>10.6 and 0.25