Morphology - Galaxy Morphology and Environment Main...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
7/11/11 Fraction of galaxies of different types plotted as function of cluster radius and projected density Galaxy Morphology and Environment Main relation – E’s more common in clusters than field f(E) = fraction of ellipticals f(Sp) = fraction of spirals regular, symmetric cluster – f(E) = 40% “ratty”, asymmetric cluster – f(E) = 15% (Oemler 1974) f(Sp) increases with R in clusters – almost no spirals in cores of clusters Dressler (1980) – first systematic study of 55 clusters with 6000 galaxies Concluded that the fundamental relation is morphology-density rather than morphology-radius However, not easy to say which is more fundamental since in clusters N ~ R-1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
7/11/11 Coma cluster – red=E; blue=spirals; green contours= X-rays
Background image of page 2
7/11/11 These substructure groupings may travel through the cluster together ü maintains a similar density for a given galaxy no matter where it is in cluster ü helps explain how morphology-density relation can be maintained even as galaxy moves throughout cluster Many clusters contain significant substructure Contour plots of projected galaxy density in clusters Bar represents 0.24 Mpc at cluster distance (Geller & Beers
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
7/11/11 What role does substructure play in dictating galaxy morphology? Sanroma & Salvador-Sole (1990) – randomize azimuthal position of galaxy in Dressler’s cluster study but preserve radial position removes small-scale substructure but preserves large-scale radial variations found morphlogy-density relation was similar to “unshuffled” data f(E) always ~50% in centers of clusters, regardless of varying central density in clusters
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 15

Morphology - Galaxy Morphology and Environment Main...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online