A NEW METHOD TO QUANTIFY X-RAY SUBSTRUCTURES IN CLUSTERS OF GALAXIES


Autoria(s): Andrade-Santos, Felipe; Lima Neto, Gastao B.; Lagana, Tatiana F.
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

24/10/2013

24/10/2013

2012

Resumo

We present a new method to quantify substructures in clusters of galaxies, based on the analysis of the intensity of structures. This analysis is done in a residual image that is the result of the subtraction of a surface brightness model, obtained by fitting a two-dimensional analytical model (beta-model or Sersic profile) with elliptical symmetry, from the X-ray image. Our method is applied to 34 clusters observed by the Chandra Space Telescope that are in the redshift range z is an element of [0.02, 0.2] and have a signal-to-noise ratio (S/N) greater than 100. We present the calibration of the method and the relations between the substructure level with physical quantities, such as the mass, X-ray luminosity, temperature, and cluster redshift. We use our method to separate the clusters in two sub-samples of high-and low-substructure levels. We conclude, using Monte Carlo simulations, that the method recuperates very well the true amount of substructure for small angular core radii clusters (with respect to the whole image size) and good S/N observations. We find no evidence of correlation between the substructure level and physical properties of the clusters such as gas temperature, X-ray luminosity, and redshift; however, analysis suggest a trend between the substructure level and cluster mass. The scaling relations for the two sub-samples (high-and low-substructure level clusters) are different (they present an offset, i. e., given a fixed mass or temperature, low-substructure clusters tend to be more X-ray luminous), which is an important result for cosmological tests using the mass-luminosity relation to obtain the cluster mass function, since they rely on the assumption that clusters do not present different scaling relations according to their dynamical state.

FAPESP [2008/05970-0, 2008/04318-7]

FAPESP

CNPq

CNPq [472012/2007-0]

Identificador

ASTROPHYSICAL JOURNAL, BRISTOL, v. 746, n. 2, supl. 1, Part 6, pp. 594-610, FEB 20, 2012

0004-637X

http://www.producao.usp.br/handle/BDPI/35949

10.1088/0004-637X/746/2/139

http://dx.doi.org/10.1088/0004-637X/746/2/139

Idioma(s)

eng

Publicador

IOP PUBLISHING LTD

BRISTOL

Relação

ASTROPHYSICAL JOURNAL

Direitos

closedAccess

Copyright IOP PUBLISHING LTD

Palavras-Chave #GALAXIES: CLUSTERS: GENERAL #GALAXIES: CLUSTERS: INTRACLUSTER MEDIUM #LARGE-SCALE STRUCTURE OF UNIVERSE #X-RAYS: GALAXIES: CLUSTERS #DYNAMICAL EVOLUTION #LINEAR-REGRESSION #MORPHOLOGIES #ASTRONOMY #EINSTEIN #HISTORY #SAMPLE #MODELS #HALOS #CORE #ASTRONOMY & ASTROPHYSICS
Tipo

article

original article

publishedVersion