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The Cosmological Constant
Type Ia supernovae

Basic Idea: Type Ia SN as standard candle, use to test kinematic effects of lambda, ie distance/redshift relation.

Systems of interest: Type Ia SN

  • What they are (believed to be): pictures
  • Usefulness as standard candle


  • Searching Method
  • Standard Candle:
    • light curve fitting
    • spectral evolution

Current Results

Criticisms and current questions

  • What are they? What is light curve relation?
    theorists at work on this
  • Evolution--rise time question
    want and are getting more
  • Low redshift sample
    getting more
  • dust: not much seen, also grey dust?
    going to higher z

Current work

  • As mentioned above--get more SN: high z and low z
  • Cepheids to calibrate (very low number)
  • Characterize better (all in a night's work)
  • Many groups

Future plans and hopes with this method

  • Better systematics
  • satellite (SNAPsat)

Other cosmological tests these can be used for

Some References

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Comments or Questions? Contact jcohn@astron.berkeley.edu