From: Chris Lidman (clidman@eso.org)
Date: Wed Oct 13 2004 - 10:08:52 PDT
Hi Serena,
I've been trying to understand 99Q a bit better. Here are some things
to things to consider.
k-corrections
-------------
Comparing table 1 in Riess's 2000 paper and your table 7, I infer the
following k-corrections
Date Reiss Ours
=================
+6.2 -0.93 -0.80
+14.5 -0.93 -1.12
+30.2 -0.93 -1.05
+32.9 -0.93 -1.05
+45.3 -0.93 -1.00
=================
Is it true that we find a decrease of 0.32 magnitudes in the
k-correction between day 6.2 and day 14.2? This seems to be a lot at
first glance.
Peak B-band magnitude from the high-z team
------------------------------------------
> From Tonry's 03 paper
Dist mod. of 99Q = 42.61
Since Tonry uses B=-19.5 as the peak magnitude of a Ia
B_max (99Q) = 23.06
If we use the photometry in table 1 of Riess et al. we would infer
B(6.2 days) = 23.31
If I use Gerson's template to work out the magnitude at maximum light, I
derive
B_max (99Q) = 23.08
So the results between Reiss 00 and Tonry 03 are consistent.
Depending on what is included and what is left out, Vitaly derives
values that vary between 23.01 and 23.35.
See http://panisse.lbl.gov/collab/archive/iband/0056.html
So, in some cases, we get a fainter peak B-band magnitude, although
we have not done an extinction correction.
On our B-band Hubble diagram, we would expect Bmax = 22.5 if s=1 at
z=0.45. Hence, 99Q is about 0.5 magnitudes fainter than the Hubble
line in the B-band. Note that I have not attempted to correct for
extinction.
On the I-band Hubble diagram, 99Q is about 0.8 magnitudes fainter than
the Hubble line if we use their photometry.
Cheers, Chris.
-- European Southern Observatory Alonso de Córdova 3107, Vitacura Casilla 19001, Santiago 19 CHILEPh. +56 2 463 3106 FAX +56 2 463 3101
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