Your SlideShare is downloading. ×
The VDDF:  Properties And Promise
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

The VDDF: Properties And Promise

314

Published on

Talk given at the AAS meeting in DC (#207, I think) about the Velocity Dispersion Distribution Function and its feasibilty to study the dynamical evolution of early-type galaxies in rich clusters.

Talk given at the AAS meeting in DC (#207, I think) about the Velocity Dispersion Distribution Function and its feasibilty to study the dynamical evolution of early-type galaxies in rich clusters.

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
314
On Slideshare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
0
Comments
0
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. Properties and Promise Robert C. Berrington Michael J. Pierce Sehyun Hwang (University of Wyoming) The Velocity Dispersion Distribution Function (VDDF) of Elliptical Galaxies: (E-mail: rberring@uwyo.edu)
  • 2. The VDDF
    • Originates from Schechter Luminosity Function
    • Transformed into velocity dispersion space (  ) via Faber-Jackson relation:
    • Takes the form:
    • Under the assumption galaxy halos are isothermal, we can convert the circular velocity (v c ) of spirals to  , and compare to Ellipticals.
  • 3. Data and Motivation
    • Total of 33 Abell clusters with an average of ~50 velocity dispersions/cluster.
      • Spectral resolution 0.9 Å (on WIYN/Hydra)
      • S/N ~30-100
      •   distribution yields VDDF
    • Tracer of galaxy gravitational potential
      • Minimal dependence on luminosity evolution.
      • Directly comparable with N-body simulations.
      • Quantitative measure of hierarchical merging?
  • 4. Individual Clusters
    • Abell 1656 (Coma)
      • Left: VDDF with best fit (solid curve)
      • Right: Error ellipses for best fit
    • Abell 548
      • Same as above
  • 5. Properties and Promise
    • Steeper low-  -end power laws (  ) have larger  * .
      • Quantitative measure of hierarchical merging?
      • Directly comparable with models
    • Weak correlation between cluster velocity dispersion (  cl ) and  * .
  • 6. Closing Statements
    • Pros
      • Minimal dependence on Luminosity evolution
      • Galaxy merging is continuous
        • Should see evolution in the VDDF for clusters at z~0.5 (versus z~1.0 for Luminosity evolution)
    • Cons
      • Cluster and galaxy evolution is stochastic
      • Requires multiple moderate resolution (R ~ 6000) spectra of galaxies—difficult at high z
  • 7.  
  • 8.  
  • 9.  
  • 10.  

×