Skip to main content

Research Repository

Advanced Search

A new method for classifying galaxy SEDs from multiwavelength photometry

Wild, Vivienne; Almaini, Omar; Cirasuolo, Michele; Dunlop, Jim; McLure, Ross; Bowler, Rebecca; Ferreira, Joao; Bradshaw, Emma; Chuter, Robert; Hartley, Will

A new method for classifying galaxy SEDs from multiwavelength photometry Thumbnail


Vivienne Wild

Professor of Astrophysics

Michele Cirasuolo

Jim Dunlop

Ross McLure

Rebecca Bowler

Joao Ferreira

Emma Bradshaw

Robert Chuter

Will Hartley


We present a new method to classify the broad-band optical–near-infrared spectral energy distributions (SEDs) of galaxies using three shape parameters (super-colours) based on a principal component analysis of model SEDs. As well as providing a compact representation of the wide variety of SED shapes, the method allows for easy visualization of information loss and biases caused by the incomplete sampling of the rest-frame SED as a function of redshift. We apply the method to galaxies in the United Kingdom Infrared Telescope Infrared Deep Sky Survey Ultra Deep Survey with 0.9 < z < 1.2, and confirm our classifications by stacking rest-frame optical spectra for a fraction of objects in each class. As well as cleanly separating a tight red sequence from star-forming galaxies, three unusual populations are identifiable by their unique colours: very dusty star-forming galaxies with high metallicity and old mean stellar age; post-starburst galaxies which have formed _10 per cent of their mass in a recent unsustained starburst event; and metal-poor quiescent dwarf galaxies.We find that quiescent galaxies account for 45 per cent of galaxies with logM∗/M_ > 11, declining steadily to 13 per cent at logM∗/M_ = 10. The properties and mass function of the poststarburst galaxies are consistent with a scenario in which gas-rich mergers contribute to the growth of the low- and intermediate-mass range of the red sequence.


Wild, V., Almaini, O., Cirasuolo, M., Dunlop, J., McLure, R., Bowler, R., …Hartley, W. (in press). A new method for classifying galaxy SEDs from multiwavelength photometry. Monthly Notices of the Royal Astronomical Society, 440(2),

Journal Article Type Article
Acceptance Date Jan 29, 2014
Online Publication Date Mar 28, 2014
Deposit Date Oct 6, 2017
Publicly Available Date Oct 6, 2017
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 440
Issue 2
Public URL
Publisher URL
Contract Date Oct 6, 2017


You might also like

Downloadable Citations