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Date: Sat, 3 Apr 93 14:07:53 PST
From: alex%bkyim.hepnet@Lbl.Gov (ALEX FILIPPENKO, UC BERKELEY, 510-642-1813)
Subject: some more info on SN 93J
4-3-93
Dear SN 1993J observers:
Here is some more information that might be of use to you.
The supernova really is fading quite rapidly. The light curves
and the spectra both suggest that it is a Type II linear, but
time will tell...
Cheers,
Alex Filippenko
****
From Steve Unger, La Palma (29146::swu):
The following table gives VERY rough magnitudes for the SN.
The V mag has an error of +/-0.2mag and the colours have +/-0.1mag.
These are external errors. The internal ones (i.e. the changes
from night to night) will be smaller - as shown by the uniform
trends.
I would only advise these as a guide, pending a full analysis.
Alan 1993 Apr 2 0500
Time V B-V U-B V-R V-I
---- - --- --- --- ---
Mar 30.9 10.78 0.05 -0.85 -- 0.18
Mar 31.1 10.85 0.10 -0.74 0.11 0.23
Mar 31.9 11.06 0.22 -0.65 0.21 0.40
Apr 01.9 11.31 0.29 -0.57 0.25 0.46
Apr 02.1 11.41 0.32 -0.49 0.26 0.50
****
From Taichi Kato (Kyoto University)
"tkato@kusastrotkato@kusastro.kyoto-u.ac.jp"
M. Okyudo (Nishiharima Observatory, Hyogo, Japan) obtained following
differential photometry of SN1993J using 0.6-m reflector + CCD.
The color band is Johnson V (uncalibrated, but the color system is
very close to the standard V).
1993 Apr. 1.660 UT SN - star A = -0.18
He also confirmed that relative magnitudes between A,B and C are
in pretty good agreement (within 0.01 mag) with those by Michael Richmond.
One may conclude that
a) Ignoring the systematic difference, the SN faded by 0.51 mag
since Richmond's observations.
b) No evidence of variability was found among the comparison stars.
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