Skip to main content

Research Repository

Advanced Search

Environments of dwarf galaxies with optical AGN characteristics

Kristensen, Mikkel; Pimbblet, Kevin; Penny, Samantha


Mikkel Kristensen

Samantha Penny


© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This study aims to explore the relation between dwarf galaxies (M∗ ≤ 5 × 109 M·) with active galactic nuclei (AGNs) and their environment by comparing neighbourhood parameters of AGN and non-AGN samples. Using the NASA-Sloan Atlas, both the local environment and the immediate environment of dwarf galaxies with z ≤ 0.055 are analysed. Of the 145 155 galaxies in the catalogue, 62 258 of them are classified as dwarf galaxies, and by employing two AGN selection methods based on emission-line fluxes (BPT and WHAN), 4476 are found to have AGN characteristics in their optical spectra. Regardless of selection method, this study finds no discernible differences in environment between AGN and non-AGN host dwarf galaxies and these results indicate that environment is not an important factor in triggering AGN activity in dwarf galaxies. This is in line with existing literature on environments of regular galaxies with AGNs and suggests universality in terms of reaction to environment across the mass regime. The biases of AGN selection in low-mass galaxies, and the biases of different measures of environment are also considered. It is found that there are several mass trends in emission-line ratios and that the SDSS fibre covers galaxies non-uniformly with redshift. These biases should be accounted for in future work by possibly including other wavelength regimes or mass weighting of emission-line ratios. Lastly, a discussion of the environment estimation methods is included since they may not gauge the desired properties due to factors such as time delay or using loosely constrained proxy parameters.


Kristensen, M., Pimbblet, K., & Penny, S. (2020). Environments of dwarf galaxies with optical AGN characteristics. Monthly notices of the Royal Astronomical Society, 496(3), 2577-2590.

Journal Article Type Article
Acceptance Date Jun 12, 2020
Online Publication Date Jun 17, 2020
Publication Date Jun 17, 2020
Deposit Date Sep 21, 2020
Publicly Available Date Oct 27, 2022
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 496
Issue 3
Pages 2577-2590
Keywords Galaxies -- active, Galaxies -- dwarf, Galaxies -- evolution
Public URL


Article (4.7 Mb)

Copyright Statement
© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

You might also like

Downloadable Citations