Concepts of Classification and Taxonomy Phylogenetic Classification

Fraix-Burnet, Didier

doi:10.1051/eas/1677010

Cited by 6 publications

(6 citation statements)

References 23 publications

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“…They do not rely on similarities, derived from the computation of distances, but on the fact that diversity is gained through evolution and speciation. For instance, similarity techniques (like most statistical clustering and classification or phenetic tools) tend to find hyperspheres in the parameter space, while phylogenetic tools are able to detect evolutionary paths as can be shown on stellar evolutionary tracks (Fraix-Burnet, 2016). Many applications have been published on many kinds of astrophysical objects (Fraix-Burnet et al, 2009, 2010, 2012Cardone and Fraix-Burnet, 2013;Fraix-Burnet and Davoust, 2015;Jofre et al, 2017;Holt et al, 2017).…”

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confidence: 99%

Phylogenetic Analyses of Quasars and Galaxies

Fraix-Burnet

D’Onofrio

Marziani

2017

Front. Astron. Space Sci.

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Phylogenetic approaches have proven to be useful in astrophysics. We have recently published a Maximum Parsimony (or cladistics) analysis on two samples of 215 and 85 low-z quasars (z < 0.7) which offer a satisfactory coverage of the Eigenvector 1-derived main sequence. Cladistics is not only able to group sources radiating at higher Eddington ratios, to separate radio-quiet (RQ) and radio-loud (RL) quasars and properly distinguishes core-dominated and lobe-dominated quasars, but it suggests a black hole mass threshold for powerful radio emission as already proposed elsewhere. An interesting interpretation from this work is that the phylogeny of quasars may be represented by the ontogeny of their central black hole, i.e. the increase of the black hole mass. However these exciting results are based on a small sample of low-z quasars, so that the work must be extended. We are here faced with two difficulties. The first one is the current lack of a larger sample with similar observables. The second one is the prohibitive computation time to perform a cladistic analysis on more that about one thousand objects. We show in this paper an experimental strategy on about 1,500 galaxies to get around this difficulty. Even if it not related to the quasar study, it is interesting by itself and opens new pathways to generalize the quasar findings.

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confidence: 99%

Phylogenetic Analyses of Quasars and Galaxies

Fraix-Burnet

D’Onofrio

Marziani

2017

Front. Astron. Space Sci.

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“…Patterns and non-trivial correlations that might go undetected in tabular-based data, can be unfolded if the proper tools are applied [58] . Among the methods that have been developed to facilitate the exploration of multivariate astronomical data are phylogenetic trees [59] , graphs, chords [58] , and starfish diagrams [60] . Figure S5 shows a dataset from a N-body/Hydro cosmological simulation [61] visualized with three different techniques.…”

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confidence: 99%

Statistical Methods in Astronomy

Long

2018

Wiley StatsRef: Statistics Reference Online

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We present a review of data types and statistical methods often encountered in astronomy. The aim is to provide an introduction to statistical applications in astronomy for statisticians and computer scientists. We highlight the complex, often hierarchical, nature of many astronomy inference problems and advocate for cross-disciplinary collaborations to address these challenges.1 ©AAS. Reproduced with permission. See [6] (doi:10.1088/0004-6256/150/5/150) for original publication.2 See

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“…The reader is referred to Fraix-Burnet et al (2015) for a review on unsupervised classification techniques in extragalactic astronomy, and to Fraix-Burnet et al (2006a,b, 2012 and Fraix-Burnet (2016) for more details on the use of cladistics in astrophysics. More explanations are available at https:// astrocladistics.org.…”

Section: Outline Of the Astrocladistics Approachmentioning

confidence: 99%

The Phylogeny of Quasars and the Ontogeny of Their Central Black Holes

Fraix-Burnet

Marziani

D’Onofrio

et al. 2017

Front. Astron. Space Sci.

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The connection between multifrequency quasar observational and physical parameters related to accretion processes is still open to debate. In the last 20 year, Eigenvector 1-based approaches developed since the early papers by Boroson and Green (1992) and Sulentic et al. (2000b) have been proven to be a remarkably powerful tool to investigate this issue, and have led to the definition of a quasar "main sequence." In this paper we perform a cladistic analysis on two samples of 215 and 85 low-z quasars (z 0.7) which were studied in several previous works and which offer a satisfactory coverage of the Eigenvector 1-derived main sequence. The data encompass accurate measurements of observational parameters which represent key aspects associated with the structural diversity of quasars. Cladistics is able to group sources radiating at higher Eddington ratios, as well as to separate radio-quiet (RQ) and radio-loud (RL) quasars. The analysis suggests a black hole mass threshold for powerful radio emission and also properly distinguishes core-dominated and lobe-dominated quasars, in accordance with the basic tenet of RL unification schemes. Considering that black hole mass provides a sort of "arrow of time" of nuclear activity, a phylogenetic interpretation becomes possible if cladistic trees are rooted on black hole mass: the ontogeny of black holes is represented by their monotonic increase in mass. More massive radio-quiet Population B sources at low-z become a more evolved counterpart of Population A i.e., wind dominated sources to which the "local" Narrow-Line Seyfert 1s belong.

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Concepts of Classification and Taxonomy Phylogenetic Classification

Cited by 6 publications

References 23 publications

Phylogenetic Analyses of Quasars and Galaxies

Phylogenetic Analyses of Quasars and Galaxies

Statistical Methods in Astronomy

The Phylogeny of Quasars and the Ontogeny of Their Central Black Holes

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