the morphology of clusters of galaxies: the cluster-galaxy connection
DESCRIPTION
The morphology of clusters of galaxies: the cluster-galaxy connection. Irini Sakelliou. Birmingham : T. Ponman MPIA : S. Falter, V. Smolcic, E. Bell MPE : A. Finoguenov Colorado: P. Motl. How structure is formed. The formation of a Coma-like cluster. Left panels : Dark matter - PowerPoint PPT PresentationTRANSCRIPT
The morphology of clusters of galaxies: the cluster-galaxy
connection
Irini Sakelliou
Birmingham : T. PonmanMPIA : S. Falter, V. Smolcic, E. BellMPE : A. FinoguenovColorado: P. Motl
Ringberg 2005
How structure is formed
The formation of a Coma-like cluster.
Left panels : Dark matterRight panels : Hot gas
Ringberg 2005
Galaxy-Cluster interactionsThey should affect both : the cluster and its
galaxies
An infalling galaxy in A2125 (z~0.25) Chandra/HST/VLA/KPNO images 01-06-04 NASA press release
Ringberg 2005
Temperature mapsContours= surface brightness
How/when and at which stage of cluster formation a) the galaxies are affected/tranformed and b) the ICM is affected by the infalling material?
Ringberg 2005
Simple measures of the structure. That it can work with X-ray and optical and
simulated images
• Centroid offset : Determination of the centre of the distribution in annuli of increasing radius. The annuli are not concentric.
• Ellipticity
• Position Angle
Ringberg 2005
Ellipticity & Position angle
Accumulation of counts (cnt) along circular annuli (). If the 2D distribution is elliptical the cnt- plot should have 2 peaks. The shape of the cnt- plot depends on the ellipticity and the position angle.
Ringberg 2005
Abell 2255XMM-Newton image in the (0.3 - 10.0) keV energy range(~14ks MOS exposure) Abell 2255 is a ~7keV at z=0.08
SDSS cluster galaxies.Red circle = XMM FOV
Ringberg 2005
High-z cluster at z=0.22 from COSMOS (Smolcic et al. 2006)
It is a poor cluster, in the process of merging with other groups. X-ray contoursRed cluster galaxiesBlue galaxies
Ringberg 2005
A2255: Centroid offset
X-rays: ICM distribution Optical : galaxy distribution
Ringberg 2005
Ellipticity & Position angle
Ringberg 2005
A2255: position angle
Ringberg 2005
Summary, Concluding remarks, & future
• A simple method to determine the dynamical ‘age’ of clusters from X-ray and optical observations
• There are still problems to be solved (e.g., errors)
• We need simple methods for determining the structure of clusters if we want to go higher redshifts
• Use simulated X-ray images to set the baseline
z= 0.25
Simulated X-ray images from Motl et al.2004
z= 0.00