University of Hertfordshire

From the same journal

From the same journal

By the same authors

Star formation and agn activity in interacting galaxies: A near-UV perspective

Research output: Contribution to journalArticlepeer-review


  • 906907

    Accepted author manuscript, 3.36 MB, PDF document

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Original languageEnglish
Pages (from-to)2137-2145
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Publication statusPublished - 21 Jan 2014


We study nearby galaxies in close pairs to study the key factors affecting star formation and active galactic nuclei (AGN) activity triggered during galaxy interactions. Close pairs are selected from the Sloan Digital Sky Survey assuming a projected separation of <30 kpc and recessional velocity difference <500 km s-1. Near-ultraviolet fluxes from GALEX are used to estimate specific star formation rates (SSFRs). We find a factor of ~5.3 increase in SSFR for low-mass (108-1011M⊙) close pair galaxies and a factor of ~2.1 increase in SSFR for highmass (1011-1013M⊙) close pairs compared to the general galaxy population. Considering galaxies of all masses, we find a factor of ~1.8 enhancement in SSFR for close pairs in field environments compared to non-pairs, with no significant increase for pairs in group and cluster environments. A modest decrease of a factor of ~1.4 is found in the Seyfert fraction in close pair galaxies when compared to isolated galaxies, which suggests that mergers may not trigger AGN activity at the close pair stage or may trigger a different class of AGN. This becomes a factor of ~4.2 decrease when we restrict our analysis to high-mass close pairs in group or cluster environments.

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