Skip to main content

Research Repository

Advanced Search

Beyond Sérsic + exponential disc morphologies in the Coma Cluster

Head, Jacob T.C.G.; Lucey, John R.; Hudson, Michael J.

Beyond Sérsic + exponential disc morphologies in the Coma Cluster Thumbnail


Authors

Jacob T.C.G. Head

Profile image of John Lucey

John Lucey john.lucey@durham.ac.uk
Emeritus Professor

Michael J. Hudson



Abstract

Galaxies are not limited to simple spheroid or bulge + disc morphologies. We explore the diversity of internal galaxy structures in the Coma Cluster across a wide range of luminosities (−17 > Mg > −22) and cluster-centric radii (0 < rcluster < 1.3r200) through analysis of deep Canada–France–Hawaii Telescope i-band imaging. We present 2D multicomponent decomposition via GALFIT, encompassing a wide range of candidate model morphologies with up to three photometric components. Particular focus is placed on early-type galaxies with outer discs (i.e. S0s), and deviations from simple (‘unbroken’) exponential discs. Rigorous filtering ensures that each model component provides a statistically significant improvement to the goodness-of-fit. The majority of Coma Cluster members in our sample (478 of 631) are reliably fitted by symmetric structural models. Of these, 134 (28 per cent) are single Sérsic objects, 143 (30 per cent) are well-described by 2-component structures, while 201 (42 per cent) require more complex models. Multicomponent Sérsic galaxies resemble compact pseudo-bulges (n ∼ 2, Re ∼ 4 kpc) surrounded by extended Gaussian-like outer structures (Re > 10 kpc). 11 per cent of galaxies (N = 52) feature a break in their outer profiles, indicating ‘truncated’ or ‘antitruncated’ discs. Beyond the break radius, truncated galaxies are structurally consistent with exponential discs, disfavouring physical truncation as their formation mechanism. Bulge luminosity in antitruncated galaxies correlates strongly with galaxy luminosity, indicating a bulge-enhancing origin for these systems. Both types of broken disc are found overwhelmingly (>70 per cent) in ‘barred’ galaxies, despite a low measured bar fraction for Coma (20 ± 2 per cent). Thus, galaxy bars play an important role in formation of broken disc structures. No strong variation in galaxy structure is detected with projected cluster-centric radius.

Citation

Head, J. T., Lucey, J. R., & Hudson, M. J. (2015). Beyond Sérsic + exponential disc morphologies in the Coma Cluster. Monthly Notices of the Royal Astronomical Society, 453(4), 3730-3753. https://doi.org/10.1093/mnras/stv1662

Journal Article Type Article
Acceptance Date Jul 21, 2015
Online Publication Date Sep 9, 2015
Publication Date Nov 11, 2015
Deposit Date Dec 22, 2015
Publicly Available Date Jan 25, 2016
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 453
Issue 4
Pages 3730-3753
DOI https://doi.org/10.1093/mnras/stv1662
Keywords Galaxies: clusters: individual: Abell 1656, Galaxies: elliptical and lenticular, cD, Galaxies: evolution, Galaxies: formation, Galaxies: structure.
Public URL https://durham-repository.worktribe.com/output/1424442
Related Public URLs http://arxiv.org/abs/1507.07930

Files

Published Journal Article (7 Mb)
PDF

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society ©: 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.






You might also like



Downloadable Citations