GOODS-Herschel: the impact of galaxy-galaxy interactions on the far-infrared properties of galaxies

Abstract

Aims. We study the impact of galaxy-galaxy interactions on the far-infrared properties of galaxies and its evolution at 0 < z < 1.2. Methods. Using the high-z galaxies in the fields of Great Observatories Origins Deep Survey (GOODS) observed by the Herschel Space Observatory in the framework of the GOODS-Herschel key program and the local IRAS or AKARI-selected galaxies in the field of Sloan Digital Sky Survey Data Release 7, we investigate the dependence of galaxy properties on the morphology of and the distance to the nearest neighbor galaxy. Results. We find that the star-formation rates (SFRs) and the specific SFRs (SSFRs) of galaxies on average depend on the morphology of and the distance to the nearest neighbor galaxy in this redshift range. When a late-type galaxy has a close neighbor galaxy, the SFR and the SSFR increase as it approaches a late-type neighbor, which is supported by Kolmogorov-Smirnov (K-S) and Monte Carlo (MC) tests with a significance level of >99%. However, the SFR and the SSFR decrease or do not change much as the galaxy approaches an early-type neighbor. The bifurcations of SFRs and SSFRs depending on the neighbor's morphology seem to occur at R n ≈ 0.5r vir,nei (virial radius of the neighbor), which is supported by K-S and MC tests with a significance level of >98%. For all redshift bins, the SSFRs of late-type galaxies interacting with late-type neighbors are increased by factors of about 1.8 ± 0.7 and 4.0 ± 1.2 compared to those of non-interacting galaxies when the pair separation is smaller than 0.5r vir,nei and 0.1r vir,nei , respectively. The dust temperature of both local and high-z late-type galaxies that strongly interact with late-type neighbors (i.e. R n ≤ 0.1r vir,nei ) appears to be higher than that of non-interacting galaxies with a significance level of 96−99%. However, the dust temperature of local late-type galaxies that strongly interact with early-type neighbors seems to be lower than or similar to that of non-interacting galaxies. Conclusions. Our results suggest that galaxy-galaxy interactions and mergers have been strongly affecting the SFR and the dust properties of star-forming galaxies over at least 8 billion years.

Clues on Arp 142: The spiral–elliptical merger

“…In this sense, what is the reason for this enhancement in SFR, considering that this enhancement is not the typical case for spirals in S+E pairs, as shown by Xu et al (2010), and more recently by Cao et al (2016). Indeed, in the case of S+E pairs, Hwang et al (2011) suggest that the X-ray emission associated with an elliptical galaxy could suppress the SFR in its companion spiral, but this seems to not be the case for NGC 2936, probably due to the mass of the elliptical companion, which is not high enough to suppress the star Figure 9. Snapshot of total mass (star+gas) for the simulated system.…”

Major-Merger Galaxy Pairs at Z = 0: Dust Properties and Companion Morphology

“…Xu et al (2012) also found no significant sSFR enhancement in massive S+E pairs at any redshift. Other authors have shown this absence of SFR enhancements in S+E pairs and low SFR of spirals with early type neighbors (Park et al 2008;Park & Choi 2009;Hwang et al 2011;Moon & Yoon 2015). Park et al (2008) suggest the hot x-ray halo of early type companions interacts hydrodynamically and deprives their paired spirals of cold gas and reduces SFRs.…”

Activity in galactic nuclei of cluster and field galaxies in the local universe

“…On the other hand, it was found that galaxy properties such as morphology, luminosity, and star formation rate (SFR) strongly depend on the distance to and the morphology of the nearest neighbor galaxy, which indicates an important role of hydrodynamic interactions with neighbor galaxies (Park et al 2008;Hwang et al , 2011. This dependence was found even when the large-scale background density is fixed, and thus is completely different from the commonly known morphology − local density relation.…”