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Sussing merger trees: the influence of the halo finder

Avila, Santiago; Knebe, Alexander; Pearce, Frazer R.; Schneider, Aurel; Srisawat, Chaichalit; Thomas, Peter A.; Behroozi, Peter; Elahi, Pascal J.; Han, Jiaxin; Mao, Yao-Yuan; Onions, Julian; Rodriguez-Gomez, Vicente; Tweed, Dylan


Santiago Avila

Alexander Knebe

Frazer R. Pearce

Aurel Schneider

Chaichalit Srisawat

Peter A. Thomas

Peter Behroozi

Pascal J. Elahi

Jiaxin Han

Yao-Yuan Mao

Julian Onions

Vicente Rodriguez-Gomez

Dylan Tweed


Merger tree codes are routinely used to follow the growth and merger of dark matter haloes in simulations of cosmic structure formation. Whereas in Srisawat et. al. we compared the trees built using a wide variety of such codes, here we study the influence of the underlying halo catalogue upon the resulting trees. We observe that the specifics of halo finding itself greatly influences the constructed merger trees.We find that the choices made to define the halo mass are of prime importance. For instance, amongst many potential options different finders select self-bound objects or spherical regions of defined overdensity, decide whether or not to include substructures within the mass returned and vary in their initial particle selection. The impact of these decisions is seen in tree length (the period of time a particularly halo can be traced back through the simulation), branching ratio (essentially the merger rate of subhaloes) and mass evolution. We therefore conclude that the choice of the underlying halo finder is more relevant to the process of building merger trees than the tree builder itself. We also report on some built-in features of specific merger tree codes that (sometimes) help to improve the quality of the merger trees produced.


Avila, S., Knebe, A., Pearce, F. R., Schneider, A., Srisawat, C., Thomas, P. A., …Tweed, D. (2014). Sussing merger trees: the influence of the halo finder. Monthly Notices of the Royal Astronomical Society, 441(4),

Journal Article Type Article
Acceptance Date Apr 20, 2014
Online Publication Date May 31, 2014
Publication Date Jul 11, 2014
Deposit Date May 9, 2017
Publicly Available Date May 9, 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 441
Issue 4
Keywords methods: numerical, galaxies: evolution, galaxies: haloes, dark matter
Public URL
Publisher URL
Copyright Statement Copyright information regarding this work can be found at the following address:


stu799Pearce.pdf (4.2 Mb)

Copyright Statement
Copyright information regarding this work can be found at the following address:

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