Investigating merging galaxies by using Pan-STARRS images^⋆

¹ Graduate Institute of Astronomy, No. 300, Zhongda Rd., Zhongli Dist., Taoyuan City 32001, Taiwan
e-mail: pcyu@astro.ncu.edu.tw
² Department of Physics, No. 300, Zhongda Rd., Zhongli Dist., Taoyuan City 32001, Taiwan
³ Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822-1839, USA
⁴ Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK

Received: 29 March 2016
Accepted: 15 December 2016

Abstract

Aims. We studied the r′-, z′-, and y′-band images of merging galaxies from the observations of the Panoramic Survey Telescope & Rapid Response System (Pan-STARRS). The merging galaxies were selected from our merging catalog that was created by checking the images of the Red-Sequence Cluster Survey 2 from the observations of the Canada France Hawaii Telescope.

Methods. By using the homomorphic-aperture, we determined the photometric results of these merging systems. To obtain accurate photometry, we calibrated the Pan-STARRS r′-, z′-, and y′-band data to match the results of Sloan Digital Sky Survey Data Release 9. We also investigated the stellar masses of the merging galaxies by comparing the Wide-field Infrared Survey Explorer 3.4 μm emission with the calibrated y′-band data.

Results. We present a catalog of the r′-, z′-, and y′-band photometric results for 4698 merging galaxies. For extended sources, our results suggest that the homomorphic-aperture method can obtain more reasonable results than the Desktop Virtual Observatory photometry. We derived new relations between the Pan-STARRS y′-band luminosities and the stellar masses of the merging galaxies. Our results show that the stellar masses of the merging galaxies range from 10⁸ to 10¹³M_⊙; some of the dry mergers could be as massive as 10¹³M_⊙.