Universität zu Köln

Clarke, S. D., Williams, G. M., Ibanez-Mejia, J. C. and Walch, S. (2019). Determining the presence of characteristic fragmentation length-scales in filaments. Mon. Not. Roy. Astron. Soc., 484 (3). S. 4024 - 4046. OXFORD: OXFORD UNIV PRESS. ISSN 1365-2966

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Abstract

Theories suggest that filament fragmentation should occur on a characteristic fragmentation length-scale. This fragmentation length-scale can be related to filament properties, such as the width and the dynamical state of the filament. Here, we present a study of a number of fragmentation analysis techniques applied to filaments, and their sensitivity to characteristic fragmentation length-scales. We test the sensitivity to both single-tier and two-tier fragmentation, i.e. when the fragmentation can be characterized with one or two fragmentation length-scales, respectively. The nearest neighbour separation, minimum spanning tree (MST) separation, and two-point correlation function are all able to robustly detect characteristic fragmentation length-scales. The Fourier power spectrum and the Nth nearest neighbour technique are both poor techniques, and require very little scatter in the core spacings for the characteristic length-scale to be successfully determined. We develop a null hypothesis test to compare the results of the nearest neighbour and MST separation distribution with randomly placed cores. We show that a larger number of cores is necessary to successfully reject the null hypothesis if the underlying fragmentation is two-tier, N greater than or similar to 20. Once the null is rejected we show how one may decide if the observed fragmentation is best described by single-tier or two-tier fragmentation, using either Akaike's information criterion or the Bayes factor. The analysis techniques, null hypothesis tests, and model selection approaches are all included in a new open-source PYTHON/C library called FRAGMENT.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Clarke, S. D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Williams, G. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Ibanez-Mejia, J. C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Walch, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-152714
DOI:	10.1093/mnras/stz248
Journal or Publication Title:	Mon. Not. Roy. Astron. Soc.
Volume:	484
Number:	3
Page Range:	S. 4024 - 4046
Date:	2019
Publisher:	OXFORD UNIV PRESS
Place of Publication:	OXFORD
ISSN:	1365-2966
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language COLLAPSE; MODEL Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/15271