Our Local Group's Microwave Background Radiation dipole

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SUMMARY

The Local Group's dipole for Microwave Background Radiation (CMB) is not aligned with the center of mass of the Local Supercluster due to the influence of the Great Attractor, which is a concentration of superclusters including the Norma cluster. The Local Group experiences a virgocentric flow of approximately 200 km/s, but the motion towards the Great Attractor is significantly faster at about 600 km/s, making it more prominent in the CMB dipole. This motion is orthogonal to the direction of the Virgo cluster, similar to Earth's motion relative to the Sun. The discrepancies in redshift measurements and the positioning of superclusters highlight the complexities of cosmic motion.

PREREQUISITES
  • Understanding of Cosmic Microwave Background (CMB) and its significance in cosmology
  • Familiarity with superclusters, specifically the Virgo and Hydra-Centaurus superclusters
  • Knowledge of redshift and its implications for cosmic distance measurement
  • Basic principles of gravitational attraction in astrophysical contexts
NEXT STEPS
  • Research the dynamics of the Great Attractor and its impact on nearby superclusters
  • Study the anisotropy of the Cosmic Microwave Background and its implications for cosmic motion
  • Explore the redshift measurements of various superclusters, focusing on the Norma cluster
  • Investigate the gravitational interactions between the Local Group and the Virgo cluster
USEFUL FOR

Astronomers, astrophysicists, and cosmologists interested in the dynamics of cosmic structures and the implications of CMB anisotropies on our understanding of the universe.

zankaon
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Why isn't our Local Group's dipole for Microwave Background Radiation pointed towards the center of mass for our Local Supercluster? Clusters are suppose to be just infalling towards gravitational well of it's supercluster. http://en.wikipedia.org/wiki/Cosmic_microwave_background"
See anisotropy velocity relative to CMB section.
 
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Because there is a greater flow than this virgocentric flow. It takes the Virgo supercluster and the Hydra-Centaurus supercluster towards the "Great Attractor". This is probably a concentration of more superclusters having the Norma cluster at its center. The virgocentric flow takes place within this "river" of matter and galaxies and is about 200 km/s. However, the motion towards the Great Attractor is about 600 km/s, and is therefore one that is more visible in the CMB dipole.
 
We could be accelerating towards the centre of the Virgo cluster, but orbiting around it.

Our motion relative to the CMB (allowing for our motion around the galactic centre) is roughly orthogonal to the direction of the centre of the Virgo cluster, just like the direction of the Earth's motion is more or less orthogonal to the direction of the Sun.

Garth
 
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zankaon said:
Why isn't our Local Group's dipole for Microwave Background Radiation pointed towards the center of mass for our Local Supercluster? Clusters are suppose to be just infalling towards gravitational well of it's supercluster. http://en.wikipedia.org/wiki/Cosmic_microwave_background"
See anisotropy velocity relative to CMB section.

Web site: http://en.wikipedia.org/wiki/Great_Attractor"
has a nice 2MASS etc. infrared sky. On large magnification, our Local Group's dipole in relation to CMB frame of reference is in direction of Hydra/Centaurus s.c.s at redshift Z .016 and .02. This is somewhat off from Shapely concentration at Z .048. This differs markedly from a Virgocentric infall. The image refers also to Norma s.c. Z .016 and nearby supposed G.A. which differs markedly from CMB dipole - contradiction? Also the text refers to Norma being near to Hydra/Centaurus - another contradiction?
 
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I don't think this is correct. Carroll & Ostlie in "An Introduction to Modern Astrophysics" mention that the Hydra-Centaurus supercluster is also being pulled by the Great Attactor. Same you can read in this page here: http://www.solstation.com/x-objects/greatatt.htm. In wikipedia you can read that it is currently assumed to have the Norma cluster in its center.
 

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