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Streaming Algorithms for Halo Finders

Zaoxing Liu, Nikita Ivkin, Lin Yang, Mark Neyrinck, Gerard Lemson, Alexander Szalay, Vladimir Braverman, Tamas Budavari, Randal Burns, Xin Wang
2015 2015 IEEE 11th International Conference on e-Science  
algorithms for finding top--largest halos were compared with convenKonal halo finders. • Low memory usage of these algorithm provide possibility to make computaKon on the laptop rather than huge computaKonal  ...  • Modify algorithms so we can use extra informaKon from spaKal-friendly storing techniques of halo finders as a funcKon of KmeFriends--of--Friends Algorithm --FOF is one of the very first halo finding  ... 
doi:10.1109/escience.2015.73 dblp:conf/eScience/LiuIYNLSBBBW15 fatcat:flbt2sexo5du7l2aazrxsriffm

Streams going Notts: the tidal debris finder comparison project

Pascal J. Elahi, Jiaxin Han, Hanni Lux, Yago Ascasibar, Peter Behroozi, Alexander Knebe, Stuart I. Muldrew, Julian Onions, Frazer Pearce
2013 Monthly notices of the Royal Astronomical Society  
test codes that find tidal debris (streams and other unbound substructure) in fully cosmological simulations of structure formation.  ...  substructure distribution (mass, velocity dispersion, position) are recovered with a scatter of ∼20 our reference, we show that the non-tracking codes identify complex tidal debris with purities of ∼40 finders  ...  Another application for these algorithms is in the study of tidally disrupted satellites like the Sagittarius stream and the Orphan stream.  ... 
doi:10.1093/mnras/stt825 fatcat:vg2fxhzdsfh7hinyp4ij56q4le

Six Dimensional Streaming Algorithm for Cluster Finding in N-Body Simulations [article]

Aidan Reilly, Vladimir Braverman Amazon, This work was done while the author was at Johns Hopkins University)
2019 arXiv   pre-print
Recent work by Liu et al (Liu et al. (2015)) showed the connection between cluster detection and memory-efficient streaming algorithms and presented a halo finder based on heavy hitter algorithm.  ...  (Ivkin et al. (2018)) improved the scalability of suggested streaming halo finder with efficient GPU implementation.  ...  The main drawback of current streaming halo finders is the need to map particle positions onto a discrete grid of cells, and inserting the ID of the cell into a data stream.  ... 
arXiv:1912.11432v1 fatcat:7vwprregujfcbdllqzvgedwgsa

Dark matter haloes: a multistream view

Nesar S. Ramachandra, Sergei F. Shandarin
2017 Monthly notices of the Royal Astronomical Society  
We propose a novel framework for detecting potential dark matter haloes using the field unique for dark matter -- multistream field.  ...  Counting the number of velocity streams in gravitational collapses supplements our knowledge of spatial clustering. We assume that the virialized haloes have convex boundaries.  ...  We also thank the anonymous referee for insightful comments on improving this paper and the editor for help with the submission.  ... 
doi:10.1093/mnras/stx1474 fatcat:hz7qszctxrfkrppv6h3v3nfg4a

Structure finding in cosmological simulations: the state of affairs

Alexander Knebe, Frazer R. Pearce, Hanni Lux, Yago Ascasibar, Peter Behroozi, Javier Casado, Christine Corbett Moran, Juerg Diemand, Klaus Dolag, Rosa Dominguez-Tenreiro, Pascal Elahi, Bridget Falck (+23 others)
2013 Monthly notices of the Royal Astronomical Society  
Here we summarize and extent previous work of the "halo finder comparison project": we investigate in detail the (possible) origin of any deviations across finders.  ...  are identified by all finders differ.  ...  Unfortunately, typical (sub)halo finders cannot be used to detect streams in galaxy formation simulations as most are configuration/density-based finders.  ... 
doi:10.1093/mnras/stt1403 fatcat:yu7dedaa5zgclcoe6s63ynb32e

Major mergers going Notts: challenges for modern halo finders

Peter Behroozi, Alexander Knebe, Frazer R. Pearce, Pascal Elahi, Jiaxin Han, Hanni Lux, Yao-Yuan Mao, Stuart I. Muldrew, Doug Potter, Chaichalit Srisawat
2015 Monthly notices of the Royal Astronomical Society  
Merging haloes with similar masses (i.e., major mergers) pose significant challenges for halo finders.  ...  We compare five halo finding algorithms' (AHF, HBT, Rockstar, SubFind, and VELOCIraptor) recovery of halo properties for both isolated and cosmological major mergers.  ...  PB, AK, PJE, JH, YYM, SIM and CS supplied halo finder data as indicated in Section 2.  ... 
doi:10.1093/mnras/stv2046 fatcat:v7avrin4tjc37ckhirlt2w2dk4

Subhaloes going Notts: the subhalo-finder comparison project

Julian Onions, Alexander Knebe, Frazer R. Pearce, Stuart I. Muldrew, Hanni Lux, Steffen R. Knollmann, Yago Ascasibar, Peter Behroozi, Pascal Elahi, Jiaxin Han, Michal Maciejewski, Manuel E. Merchán (+5 others)
2012 Monthly notices of the Royal Astronomical Society  
(sub-)halo finders for simulations of cosmic structure formation.  ...  These finders span a wide range of techniques and methodologies to extract and quantify substructures within a larger non-homogeneous background density (e.g. a host halo).  ...  Haloes are identified with a Friends-of-Friends (FOF) algorithm and halo merger trees are constructed.  ... 
doi:10.1111/j.1365-2966.2012.20947.x fatcat:alwua747bvbd3nnhf2ismm7izy

Phase-space structures - II. Hierarchical Structure Finder

M. Maciejewski, S. Colombi, V. Springel, C. Alard, F. R. Bouchet
2009 Monthly notices of the Royal Astronomical Society  
If an additional unbinding criterion is added, the algorithm can be used as a self-consistent halo and subhalo finder.  ...  phase-space structures such as pure streams and candidate caustics.  ...  White for many important suggestions and G. Lavaux, R. Mohayaee and D. Weinberg for useful discussions. Part of this work was completed during a visit of MM and SC at MPA/Garching.  ... 
doi:10.1111/j.1365-2966.2009.14825.x fatcat:a5nltcgp3fhkrl3ndak7nahos4

THE ROCKSTAR PHASE-SPACE TEMPORAL HALO FINDER AND THE VELOCITY OFFSETS OF CLUSTER CORES

Peter S. Behroozi, Risa H. Wechsler, Hao-Yi Wu
2012 Astrophysical Journal  
We present a new algorithm for identifying dark matter halos, substructure, and tidal features.  ...  We show a significant improvement in substructure recovery as compared to several other halo finders and discuss the theoretical and practical limits of simulations in this regard.  ...  In addition, the halo finder complements the method of Behroozi et al. (2011) for creating merger trees, making it part of the first halo finding system to recover halos using seven dimensions of information  ... 
doi:10.1088/0004-637x/762/2/109 fatcat:engjhehlujg3tiwt7leefy7kqe

Halo Merger Tree Comparison: Impact on Galaxy Formation Models [article]

Jonathan S. Gómez, Nelson D. Padilla, John C. Helly, Cedric G. Lacey, Carlton M. Baugh, Claudia del P. Lagos
2021 arXiv   pre-print
We examine the effect of using different halo finders and merger tree building algorithms on galaxy properties predicted using the GALFORM semi-analytical model run on a high resolution, large volume dark  ...  these four halo finders/tree builders.  ...  finder, provided that the halo trees are prepocessed by the Dhalo algorithm.  ... 
arXiv:2106.12664v1 fatcat:hyjxjctin5gh3pr2iwllmrgz7e

Bound and unbound substructures in Galaxy-scale dark matter haloes

Michal Maciejewski, Mark Vogelsberger, Simon D. M. White, Volker Springel
2011 Monthly notices of the Royal Astronomical Society  
We analyse the coarse-grained phase-space structure of the six Galaxy-scale dark matter haloes of the Aquarius Project using a state-of-the-art 6D substructure finder.  ...  The slope of the differential substructure mass function is close to -2, which should be compared to around -1.9 for the population of self-bound subhaloes.  ...  Recently Maciejewski et al. (2009a) presented an algorithm, Hierarchical Structure Finder (HSF), designed specifically for this purpose.  ... 
doi:10.1111/j.1365-2966.2011.18871.x fatcat:rgqqcbleybgm7gqvwsngjao5ei

Introducing a new, robust galaxy finder algorithm for simulations [article]

Rodrigo Cañas, Pascal J. Elahi, Charlotte Welker, Claudia del P. Lagos, Chris Power, Yohan Dubois, Christophe Pichon
2018 arXiv   pre-print
We present a new scale-free shape-independent algorithm to robustly and accurately identify galaxies in simulation, implemented within the phase-space halo-finder code VELOCIraptor.  ...  We apply our improved method to the Horizon-AGN simulation and compare galaxy stellar masses (M_*), star formation rates (SFR) and sizes with the elaborate configuration-space halo finder, HaloMaker.  ...  We thank Stephane Rouberol for running smoothly this cluster for us.  ... 
arXiv:1806.11417v1 fatcat:fp7nrb4zyfhuni6w3j5tzo5dxm

Subhaloes gone Notts: the clustering properties of subhaloes

Arnau Pujol, Enrique Gaztañaga, Carlo Giocoli, Alexander Knebe, Frazer R. Pearce, Ramin A. Skibba, Yago Ascasibar, Peter Behroozi, Pascal Elahi, Jiaxin Han, Hanni Lux, Stuart I. Muldrew (+4 others)
2014 Monthly notices of the Royal Astronomical Society  
We run 11 different subhalo finders on the haloes of the Aquarius Simulation and we study their differences in the density profile, mass fraction and 2-point correlation function of subhaloes in haloes  ...  We discuss implications of our results for models of subhalo clustering and their relation with galaxy clustering.  ...  The other authors provided results and descriptions of their algorithms as well as having an opportunity to proof read and comment on the paper.  ... 
doi:10.1093/mnras/stt2446 fatcat:fyxisywoz5bybgl2hqpv6b5esa

Subhaloes gone Notts: spin across subhaloes and finders

Julian Onions, Yago Ascasibar, Peter Behroozi, Javier Casado, Pascal Elahi, Jiaxin Han, Alexander Knebe, Hanni Lux, Manuel E. Merchán, Stuart I. Muldrew, Mark Neyrinck, Lyndsay Old (+6 others)
2013 Monthly notices of the Royal Astronomical Society  
We present a study of a comparison of spin distributions of subhaloes found associated with a host halo.  ...  We employ ten different substructure finders, which span a wide range of methodologies from simple overdensity in configuration space to full 6-d phase space analysis of particles.We subject the results  ...  For each halo we calculate the spin parameter at 0.25, 0.5, 0.75 and 0.95 of the subhalo's total mass for all the contributing halo finders.  ... 
doi:10.1093/mnras/sts549 fatcat:mm2x6phr6fe2vggjak7igpqz2y

The halo finding problem revisited: a deep revision of the ASOHF code [article]

David Vallés-Pérez, Susana Planelles, Vicent Quilis
2022 arXiv   pre-print
We present a public, deeply revised version of the ASOHF halo finder.  ...  When applied to realistic data from simulations, the performance of our finder is fully consistent with the results from other commonly used halo finders, with remarkable performance in substructure detection  ...  We thank the anonymous referee for his/her constructive comments, which have improved the presentation of this work. This  ... 
arXiv:2205.02245v1 fatcat:gbudas2tbjd3rk72ly4mtr34ri
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