Hubble data on 11 Type Ia supernova puts constraints on Dark Energy

Discussion in 'Astronomy, Exobiology, & Cosmology' started by thed, Oct 2, 2003.

  1. thed IT Gopher Registered Senior Member

    Messages:
    1,105
    Press release can be read here. The paper submitted to ApJ can be read here.


    Edited to add, <a href="http://supernova.lbl.gov/">Also read the Supernova Cosmology Project</a>
     
  2. Mark Registered Senior Member

    Messages:
    150
    thed thanks for posting this
    and especially for including the link to the preprint
    so one can go directly to the paper itself and skip
    the press release

    it looks as if the percentage estimates of dark matter and
    energy did not shift significantly but just got more
    reliable and sharply defined

    what seems remarkable is that with the prevailing assumption
    of flatness they have a handle on the "equation-of-state"
    parameter "w" of dark energy
    if it has been constant over time they say it is pretty close to
    -1, which has been assumed by other people but with less confidence

    in case anyone is curious about w, it being minus one means that the pressure exerted by dark energy equals -1 times it's energy density. w being negative is what makes the pressure negative----which when plugged into the cosmological model (Friedmann equation) accelerates the expansion, so w is a good thing to have an observational grip on

    glad to see this, appreciate your posting it!
     

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