From: Robert A. Knop Jr. (robert.a.knop@vanderbilt.edu)
Date: Tue May 20 2003 - 11:07:20 PDT
On Tue, May 20, 2003 at 10:24:16AM -0700, Greg Aldering wrote:
>
> Hi Rob,
>
> The differences I find between the old and new kcor1 are much larger
> than you describe. I fully admit that I may be misunderstanding
> something here, but so you can see what I'm talking about, here is a
> table of oldkcor1-newkcor1 versus redshift for P99 SNe:
There's something wrong with the old gersontable, then.
Consider one example:
> z kcor1 diff
> ----------------------
> 0.495 0.172
This is SN 969.
Looking at the file:
/home/astro34/aldering/njnunes/minuit/SNMIN_22jul98/Output_ri/snminuit_sn969.ps
I see kcorr_R=-0.714.
I've got kcorr1=-0.712 in my table.
The kcorr1 values in the old gersontable don't seem to correspond to the
kcorrs from the snminuit fits. As such, before we get worried about
differences, we need to figure out what was going on there.
...in fact, looking at my copy of the old gerson table, I see -0.714 in
there. I think you're just looking at the wrong column.
> The differences are not only large (perhaps a definition change?), but
> 9739 stands out from the trend.
That's because of what I said earlier -- 9739 formally has E(B-V)=-0.8,
and it's at a bad redshift, which would tend to make it's K-correction
value stand out by 0.2-0.3 magnitudes.
> If there is a good explaination for this, then I guess my next concern
> would be in publishing this new magnitude for 9739 since the difference
> - using the same data - is well outside the quoted uncertainty.
Then the thing to do is make that d(R-I)<0.25 color error cut I talked
about earlier, which eliminates another 4 P99 SNe. (It would cut out 5,
but one of them is cut by one of the other cuts.)
Should I proceed with this?
-Rob
-- --Prof. Robert Knop Department of Physics & Astronomy, Vanderbilt University robert.a.knop@vanderbilt.edu
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