[vsnet-obs 27733] SN observation (APO)

[Hitoshi YAMAOKA <yamaoka@rc.kyushu-u.ac.jp>]

>Subject: SNe 2000bk, 2000ce, 2000cf
Date: Mon, 15 May 2000 14:08:43 -0700 (PDT)
From: Kevin Krisciunas <kevin@lensing.astro.washington.edu>

After a good clear night on May 11th UT, I conclude that the field
star calibration for 2000bk needed revision, especially the V-I
colors.  I have updated that at my website:

http://vsnet.astro.washington.edu/kevin/apo.html

We got good images on 2000ce on May 11th, and also 2000cf.  See my 
website.  Plus, we got JHK near infrared photometry of 2000ce and an 
H-band measure on 2000cf.  However, cf is awfully close to its host
nucleus, so there is a serious gradient in the galaxy light near it.  
Aperture photometry should be OK on 2000ce, but not the IR measure
on cf, really.

I would say that 2000ce is a much better target than cf.  Though it
is quite far west, at 8 hours RA, it is far north, so can be observed
quite far into the evening.  And it is brighter.

Here's what I sent Dan Green at the IAUC office today:

SUPERNOVA 2000ce IN UGC 4195

K. Krisciunas and A. Rest (Univ. of Washington) report preliminary
photometry obtained by Rest and R. McMillan (Apache Point
Observatory), using the APO 3.5-m telescope.  On May 11.12 UT we find
V = 16.92, B-V = +0.74, V-R = +0.35, V-I = +0.33, with uncertainties
of +/- 0.03 mag. A software aperture of diameter 4.5 arcsec was used.
We also find on May 11.25 UT infrared magnitudes of J = 16.65 +/-
0.07, H = 15.85 +/- 0.07, K = 15.99 +/- 0.10, using a software
aperture of diameter 5.7 arsec and a sky annulus of radius 5.7 to 9.5
arcsec.  If the estimated time of maximum light (IAUC 7422) of May 4
is correct and this object's V minus near infrared color evolution is
similar to the supernovae studied by Krisciunas et al. (1999,
astro-ph/9912219), then the extinction along the line of sight to this
object is roughly A_V = 2.3 mag, which would explain the red B-V color
so soon after maximum.  

SUPERNOVA 2000cf IN MCG +11-19-25

K. Krisciunas, A. Rest, and R. McMillan report preliminary photometry,
obtained as for 2000ce.  On May 11.18 UT we find V = 17.09, B-V =
+0.08, V-R = +0.10, V-I = -0.11, with uncertainties of +/- 0.03 mag.
Near infrared photometry of May 11.27 UT yields H = 16.79 +/- 0.14,
but is affected by a rather serious gradient in the underlying galaxy
light. 

Kevin

--------
reformatted:

SN2000ce  20000511.12   16.92V   APO
SN2000ce  20000511.12   17.66B   APO
SN2000ce  20000511.12   16.57R   APO
SN2000ce  20000511.12   16.59I   APO
SN2000ce  20000511.25   16.65J   APO
SN2000ce  20000511.25   15.85H   APO
SN2000ce  20000511.25   15.99K   APO
SN2000cf  20000511.18   17.09V   APO
SN2000cf  20000511.18   17.17B   APO
SN2000cf  20000511.18   16.99R   APO
SN2000cf  20000511.18   17.20I   APO
SN2000cf  20000511.27   16.79:H  APO

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