Re: poor agreement with Riess 99

From: Greg Aldering (aldering@panisse.lbl.gov)
Date: Wed May 07 2003 - 18:24:17 PDT

  • Next message: Alex Conley: "Re: poor agreement with Riess 99"

    HERE IS THE REVISED VERSION:

    Hi Rob,

    I started to investigate "what'sup" with SN1995bd and SN1996bo and
    found that your B-band magnitudes differ, sometimes by a lot, from the
    published Bmax tables from Table 3 of Riess 1999 (the 22 SNe paper).
    Further investigation showed generally poor agreement. Can you
    comment?

                no extinction cor
                Bmax mB mBcor Bmx-mB
                 R99 SCP03 SCP03
    ---------------------------------------------------------------------------
    SN1995bd 17.27 15.32 17.39 HUGE! (weird that mB_cor is much better)
    SN1996bo 16.15 15.85 15.92 +0.30

    also, here are the other Riess 1999 SNe for comparison

    SN1994M 16.35 16.25 16.13 +0.10
    SN1994S 14.79 14.78 14.93 +0.01
    SN1995ac 17.19 17.05 17.37 +0.14
    SN1996bl 17.08 16.67 17.14 +0.41 way off!

    These seem like large differences (some extremely large) given the
    small uncertainty you quote from fitting the same data (few tenths of a
    magnitude). Some of this is probably due to the crudeness of the
    delta-m15 fits quoted in Riess 1999. I seem to recall that in P99 we
    may have had a similar issue with the H96 data, but I haven't checked
    that yet.

    These offsets aren't enough to explain the anomalous extinction for
    95bd and 96bo, unless the extinction estimate is off. So, I looked at
    your E(B-V) values and compared them to the value in Phillips 1999

                  your ph99 tail ph99 peak
                 E(B-V) E(B-V) E(B-V)
    ------------------------------------------------------
    SN1995bd 0.339 0.242 NOT GIVEN - dm15 < 0.9
    SN1996bo 0.390 0.358 0.385

    So here, the agreement for E(B-V) at max for 96bo is good. 95bd may be
    another question, but it isn't as big an outlier as 96bo in the
    extinction-corrected fits.

    On to more data sifting.

    - Greg



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