From: Gerson Goldhaber (g_goldhaber@lbl.gov)
Date: Fri Jul 09 2004 - 14:00:18 PDT
Dear Mamoru, Naoki and Chris,
In preparation for our collaboration meeting I am looking at the
Subaru data in greater detail. Let me first state that these SNe are an
excellent sample which should give us important cosmological information.
There are 13 SNe with unknown redshift.
From the lightcurve fits, and particularly the maximum magnitudes, I
got a very rough estimate of the expected redshifts.
z > 1.3 SuF02-076, -086
z > 1 SuF02-J01, -051, -057, -014, -004, -J02
z 0.9 to 1 SuF02-058, -056
z < 0.8 SuF02-034, SXDS_2-9, SXDS_2-4
Is there any information from photo-z, or could we get host galaxy spectra?
Together with the measured redshifts, there is thus a potentially very
substantial set of SNe with z > 1, namely 16.
Other comments.
1. I have plotted the SNe with known redshift on a Hubble plot,for our
favorit cosmology and find that the SNe magnitudes are dimmer than
expected by about 0.7 mag. ie. they follow the hubble curve with larger
magnitudes by about this offset. Calibration?
2. As I mentioned before, I question the calibration on Julian day
52616. Data taken on this day is high in normalized flux, with respect
to all other dates. This was noticeable in SNe : SuF02-000, -004, -012,
-019, -057, -081. The correction factor needed to bring these point in
agreement with the other data points is about 0.7 in flux.
3. Other SNe with some apparently inconsistent points are: SuF02-007,
-017, -034, -065, -071, -082
4.Two SNe SuF02-019 and -082 appear too dim by about 1.5 magnitudes.
Could they be at a higher redshift??
5.Two of the SNe SuF2-014 and -081 have exceptionally small stretch,
about 0.45. In our earlier study we had one such SN,
sn9571 at z=0.866, which Greg had studied. These 3 form a rather unique
set which needs to be explained. The one other SN I know of in the
Hamuy et al SN sn1992br with stretch measured between 0.53 to 0.63
(depending on the details of the fit). Alex Conley has several with
stretch arround somewhat over 0.6.
Hopefully we will be able to resolve some of these matters at our
collaboration meeting.
cheers Gerson
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