The evolution of merger fraction of galaxies at z < 0.6 depending on the star formation mode in the AKARI NEP Wide field

TL;DR

This study investigates how galaxy merger fractions at z<0.6 vary with star formation modes, revealing higher merger activity in starbursts and Herschel-detected galaxies, with merger fractions increasing over redshift.

Contribution

It provides new insights into the dependence of galaxy merger fractions on star formation modes and infrared detection status at low redshifts.

Findings

Merger fractions increase with redshift at z<0.6.

Starburst galaxies have higher merger fractions than main sequence and quiescent galaxies.

Herschel-detected galaxies exhibit higher merger fractions than non-detected ones.

Abstract

We study the galaxy merger fraction and its dependence on star formation mode in the5.4 square degrees of the North Ecliptic Pole-Wide field. We select 6352 galaxies withAKARI 9{\mu}m detections, and identify mergers among them using the Gini coefficientand M20derived from the Subaru/HSC optical images. We obtain the total infraredluminosity and star formation rate of galaxies using the spectral energy distributiontemplates based on one band, AKARI 9{\mu}m. We classify galaxies into three differentstar formation modes (i.e. starbursts, main sequence, and quiescent galaxies) andcalculate the merger fractions for each. We find that the merger fractions of galaxiesincrease with redshift atz<0.6. The merger fractions of starbursts are higher thanthose of main sequence and quiescent galaxies in all redshift bins. We also examinethe merger fractions of far-infrared detected galaxies which have at least one detectionfromHerschel/SPIRE. We find thatHerscheldetected galaxies have higher mergerfraction compared to non-Herscheldetected galaxies, and bothHerscheldetected andnon-Herscheldetected galaxies show clearly different merger fractions depending onthe star formation modes.