Hunting for galaxies and halos in simulations with VELOCI raptor

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

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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 ‰310-2 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.

Original languageEnglish
JournalPublications of the Astronomical Society of Australia
DOIs
Publication statusE-pub ahead of print - 1 Jan 2019

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raptor
hunting
halos
galaxies
simulation
friction
application programming interface
particle tracks
data products
messages
substructures
mass ratios
code
configurations

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title = "Hunting for galaxies and halos in simulations with VELOCI raptor",
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 ‰310-2 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.",
keywords = "dark matter, galaxies: evolution, galaxies: halos, methods: numerical",
author = "Elahi, {Pascal J.} and Rodrigo Ca{\~n}as and Poulton, {Rhys J.J.} and Tobar, {Rodrigo J.} and Willis, {James S.} and Lagos, {Claudia Del P.} and Chris Power and Robotham, {Aaron S.G.}",
year = "2019",
month = "1",
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doi = "10.1017/pasa.2019.12",
language = "English",
journal = "Publications of the Astronomincal Society of Australia (PASA)",
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}

Hunting for galaxies and halos in simulations with VELOCI raptor. / 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.

In: Publications of the Astronomical Society of Australia, 01.01.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Hunting for galaxies and halos in simulations with VELOCI raptor

AU - Elahi, Pascal J.

AU - Cañas, Rodrigo

AU - Poulton, Rhys J.J.

AU - Tobar, Rodrigo J.

AU - Willis, James S.

AU - Lagos, Claudia Del P.

AU - Power, Chris

AU - Robotham, Aaron S.G.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - 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 ‰310-2 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.

AB - 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 ‰310-2 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.

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