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Hunting for galaxies and halos in simulations with VELOCIraptor

Elahi, Pascal J.; Cañas, Rodrigo; Poulton, Rhys J.J.; Tobar, Rodrigo J.; Willis, James S.; Lagos, Claudia del P.; Power, Chris; Robotham, Aaron S.G.

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Authors

Pascal J. Elahi

Rodrigo Cañas

Rhys J.J. Poulton

Rodrigo J. Tobar

James S. Willis

Claudia del P. Lagos

Chris Power

Aaron S.G. Robotham



Abstract

We present VELOCIraptor, a massively parallel galaxy/(sub)halo finder that is also capable of robustly identifying tidally disrupted objects and separate stellar halos from galaxies. The code is written in C++11, use the Message Passing Interface (MPI) and OpenMP Application Programming Interface (API) for parallelisation, and includes python tools to read/manipulate the data products produced. We demonstrate the power of the VELOCIraptor (sub)halo finder, showing how it can identify subhalos deep within the host that have negligible density contrasts to their parent halo. We find a subhalo mass-radial distance dependence: large subhalos with mass ratios of ≳10−2 are more common in the central regions than smaller subhalos, a result of dynamical friction and low tidal mass loss rates. This dependence is completely absent in (sub)halo finders in common use, which generally search for substructure in configuration space, yet is present in codes that track particles belonging to halos as they fall into other halos, such as hbt+. VELOCIraptor largely reproduces the dependence seen without tracking, finding a similar radial dependence to hbt+ in well-resolved halos from our limited resolution fiducial simulation.

Citation

Elahi, P. J., Cañas, R., Poulton, R. J., Tobar, R. J., Willis, J. S., Lagos, C. D. P., …Robotham, A. S. (2019). Hunting for galaxies and halos in simulations with VELOCIraptor. Publications of the Astronomical Society of Australia, 36, Article e021. https://doi.org/10.1017/pasa.2019.12

Journal Article Type Article
Online Publication Date Jan 1, 2019
Publication Date Jan 30, 2019
Deposit Date Aug 2, 2019
Publicly Available Date Mar 28, 2024
Journal Publications of the Astronomical Society of Australia
Print ISSN 1323-3580
Electronic ISSN 1448-6083
Publisher Cambridge University Press
Peer Reviewed Peer Reviewed
Volume 36
Article Number e021
DOI https://doi.org/10.1017/pasa.2019.12

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