How galaxies are affected by their neighboring galaxies during galaxy-galaxy interactions is a long- standing question. We investigate the role of neighbors in galaxy pairs based on the SDSS data release 7 and the KIAS value-added galaxy catalog. Three groups of galaxies are identified: (a) galaxies with an early-type neighbor, (b) with a late-type neighbor, and (c) isolated ones with no neighbor. We compare their UV + optical colors and Hα emission as indicators of the recent star-formation rate (SFR). Given that galaxies show systematic differences in SFR as functions of morphology, luminosity, and large-scale environments, we construct a control sample in which the galaxies have the same conditions (in terms of morphology, luminosity, and large-scale environment) except for the neighbor's properties (i.e., morphol- ogy, mass, and distance). The results are as follows. (1) Galaxies with a late-type companion demonstrate more enhanced SFR than those with an early-type companion. (2) Galaxies with an early-type neighbor show NUV- and u-band derived SFRs that are even lower than that of isolated galaxies, while they have similar or slightly higher Hα-based SFR compared to isolated ones.

ABSTRACT
1. INTRODUCTION
2. METHODOLOGY
3. RESULTS
REFERENCES

• Jun-Sung Moon(Department of Astronomy & Center for Galaxy Evolution Research, Yonsei University)
• Suk-Jin Yoon(Department of Astronomy & Center for Galaxy Evolution Research, Yonsei University)