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Far-ultraviolet morphology of star-forming filaments in cool core brightest cluster galaxies

Tremblay, G.R.; O'Dea, C.P.; Baum, S.A.; Mittal, R.; McDonald, M.A.; Combes, F.; Li, Y.; McNamara, B.R.; Bremer, M.N.; Clarke, T.E.; Donahue, M.; Edge, A.C.; Fabian, A.C.; Hamer, S.L.; Hogan, M.T.; Oonk, J.B.R.; Quillen, A.C.; Sanders, J.S.; Salomé, P.; Voit, G.M.

Far-ultraviolet morphology of star-forming filaments in cool core brightest cluster galaxies Thumbnail


G.R. Tremblay

C.P. O'Dea

S.A. Baum

R. Mittal

M.A. McDonald

F. Combes

Y. Li

B.R. McNamara

M.N. Bremer

T.E. Clarke

M. Donahue

A.C. Fabian

S.L. Hamer

M.T. Hogan

J.B.R. Oonk

A.C. Quillen

J.S. Sanders

P. Salomé

G.M. Voit


We present a multiwavelength morphological analysis of star-forming clouds and filaments in the central (≲50 kpc) regions of 16 low-redshift (z < 0.3) cool core brightest cluster galaxies. New Hubble Space Telescope imaging of far-ultraviolet continuum emission from young (≲10 Myr), massive (≳5 M⊙) stars reveals filamentary and clumpy morphologies, which we quantify by means of structural indices. The FUV data are compared with X-ray, Lyα, narrow-band Hα, broad-band optical/IR, and radio maps, providing a high spatial resolution atlas of star formation locales relative to the ambient hot (∼107–8 K) and warm ionized (∼104 K) gas phases, as well as the old stellar population and radio-bright active galactic nucleus (AGN) outflows. Nearly half of the sample possesses kpc-scale filaments that, in projection, extend towards and around radio lobes and/or X-ray cavities. These filaments may have been uplifted by the propagating jet or buoyant X-ray bubble, or may have formed in situ by cloud collapse at the interface of a radio lobe or rapid cooling in a cavity's compressed shell. The morphological diversity of nearly the entire FUV sample is reproduced by recent hydrodynamical simulations in which the AGN powers a self-regulating rain of thermally unstable star-forming clouds that precipitate from the hot atmosphere. In this model, precipitation triggers where the cooling-to-free-fall time ratio is tcool/tff ∼ 10. This condition is roughly met at the maximal projected FUV radius for more than half of our sample, and clustering about this ratio is stronger for sources with higher star formation rates.


Tremblay, G., O'Dea, C., Baum, S., Mittal, R., McDonald, M., Combes, F., …Voit, G. (2015). Far-ultraviolet morphology of star-forming filaments in cool core brightest cluster galaxies. Monthly Notices of the Royal Astronomical Society, 451(4), 3768-3800.

Journal Article Type Article
Publication Date Aug 1, 2015
Deposit Date Oct 28, 2015
Publicly Available Date Nov 4, 2015
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 451
Issue 4
Pages 3768-3800
Keywords Galaxies: active, Galaxies: clusters: general, Galaxies: clusters: intracluster medium, Galaxies: star formation
Publisher URL


Published Journal Article (3.2 Mb)

Copyright Statement
This article has been published 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.

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