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\IBVShead{4312}{22 March 1996}                                               
                                                                                
\centerline{\ft OPTICAL OBSERVATIONS OF SN 1996C IN MCG+08-25-47}               
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\begintext                                                                      
                                                                                
                                                                                
Supernova (SN) 1996C in MCG+08-25-47 was discovered on 1996 Feb. 15 (UT)        
by J. Mueller (1996) on a IV-N plate obtained by herself and K. M.              
Rykoski in the course of the second Palomar Sky Survey.                         
Precise positions were measured by Sicoli (1996) on UT Feb. 22.99 and
by Balam (1996) on UT Feb. 24.47. The offset from the center of the
galaxy was determined to be 13\farcs 4 north and 1\farcs 6 west of the galaxy's
nucleus.                                                                      
Garnavich et al. (1996) provided confirmation of SN 1996C from an
image obtained by J. Luu with the 1.2-m telescope at Mt. Hopkins on
UT Feb. 17.5. The supernova was estimated to be V = 16.                        
In addition, a spectrogram of SN 1996C was obtained by D. Koranyi (1996) using
the 1.5-m Tillinghast telescope, showing SN 1996C to be a type-Ia
supernova near maximum. Weak H$\alpha$ emission from the host galaxy
indicated a redshift of z = 0.027.                                                               
 
Photometric and astrometric observations of SN 1996C were obtained on  
four nights using the 1.82-m Plaskett telescope and SITe-1 charge-coupled
device (CCD) of the Dominion Astrophysical Observatory. All CCD frames
were bias subtracted and flat fielded,                                                                               \vskip 5mm
\epsfysize=9.5cm                                                                 
\centerline{\epsffile{4312-f1.ps}}                                                
\begin{center}                                                                  
Figure 1. Secondary standard stars near MCG+08-25-47                            
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\centerline{Table 1. Photometric standard stars near MCG+08-25-47}
\begin{center}
\begin{tabular}{ccccc} 
\hline
Star & (2000)  &(2000) & V & B$-$V \\ 
\hline
\\
A& 13\fh 50\fmm 47\fss 81 & +49\degr 18\farcmm 38\farcs 9&14.93 (0.01)& +0.56 (0.01)\\
B& 13\fh  51\fmm  07\fss 46 & +49\degr 18\farcmm 28\farcs 9 & 16.76 (0.01)& +0.55 (0.02)\\
C& 13\fh  50\fmm  52\fss 79 & +49\degr 17\farcmm 05\farcs 5 & 16.59 (0.03)& +1.00 (0.03)\\
D& 13\fh  50\fmm  56\fss 47 & +49\degr 16\farcmm 01\farcs 0 & 17.31 (0.06)& +0.93 (0.06)\\ \hline
\end{tabular}
\end{center}

\vskip 4mm

\noindent using median filtered twilight
flats, in the usual manner using IRAF\footnote{IRAF is distributed
by National Optical Observatories, which is operated by the Association
of Universities for Research in Astronomy, Inc., under contract to the
National Science Foundation}. Local photometric standard stars from the
Guide Star Photometric Catalog (Lasker et al., 1988) were observed at 
the same airmass as the supernova field. The data has been brought to
the standard system using color transformation coefficients that were
determined by observation of the M92 standard stars of Christian et al.
(1985).

A photometric sequence of secondary standard stars (Figure 1) was 
established in the field of MCG+08-25-47 and are listed in Table 1.
The astrometric positions of the secondary standard stars were calculated
from a frame constants solution involving six Guide Star Catalog (GSC)
stars (Jenkner et al., 1990). The mean error, within the polygon of GSC
stars, was determined to be 0\farcs 6. A detailed description of our astrometric
reduction techniques can be found in Tatum et al. (1994).  
 

Differential magnitudes and colors of SN 1996C are listed in Table 2
for four nights (UT Feb. 24, 25, March 1, and March 14). The photometry was
performed using the (IRAF) PHOT routine with a measuring aperture of 2\farcs 8 
and sky annulus of 19" radius.  The FWHM of the stars was determined as 2\farcs 4.
 The comparison and check stars are labelled as stars A and B in Table 1 and
Figure 1.
The standard deviation of all nightly comparison $-$ check star 
differential magnitudes was 0.012 and 0.011 magnitudes in the
B and V filter images.



Supernova 1996C is located 14'' north of the core of its host galaxy.
The host galaxy can be detected as far as 23'' north of the galaxy core.
Contamination of the supernova observations by the host galaxy
has been minimized by building  models of the host galaxy using
elliptical isophotal fitting (Jedrzejewski, 1987), as implemented
with the IRAF routines ELLIPSE and BMODEL in the STSDAS
package, and subtracting the model galaxies from the original images.
Errors, induced by the modelling process, have been estimated by 
placing artificial SNe in areas of the host galaxy
that have similar surface brightness and gradient to the region
containing SN 1996C. The mean error induced by the modelling process
is 0.02 in the B images and 0.01 in V images. The resultant 
galaxy subtracted observations are listed in Table 2 as
$V_{sub}$ and $B-V_{sub}$.



Preliminary fitting (Figure 2) of the V band light curve template of
Leibundgut (1988) to the galaxy-modelled observations of Table 2
implies that (B) maximum occurred on UT 1996 Feb. 15 (JDT 2450128)
when SN 1996C was apparent magnitude V = 16.65.



The author wishes to acknowledge G.C.L. Aikman (Dominion
Astrophysical Observatory), for obtaining the UT Mar. 14 images
of SN 1996C, and F.D.A. Hartwick and the Natural Sciences and
Engineering Research Council (NSERC) of Canada for their support
in this work.
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\centerline{3}
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                                                                           \centerline{Table 2. Observations of SN 1996C}                                  
\begin{center}                                                                  
\begin{tabular}{ccccc} 
\hline                                            
JDE    & $V_{Sub}$ & $B-V_{Sub}$ & V & B$-$V  \\ 
\hline                           
(2450000+)& & \\ 
\hline                                                         
137.97 & 16.87 (0.01) & +0.08 (0.02) & 16.72 (0.02) & +0.11 (0.02) \\           
138.90 & 16.91 (0.02) & +0.14 (0.03) & 16.73 (0.02) & +0.16 (0.03) \\           
143.89 & 17.21 (0.01) & +0.33 (0.02) & 17.00 (0.02) & +0.37 (0.03) \\     
156.90 & 18.09 (0.01) & +0.81 (0.05) & 17.94 (0.02) & +0.92 (0.04) \\ 
\hline
\end{tabular}                                                                   
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\centerline{\epsffile{4312-f2.ps}}                                              
\begin{center}                                                                  
Figure 2. Light curve (V) of SN 1996C                                           
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\beginauthors 
\authorsrightcol                                                                  
D.D. BALAM                                                                     
Dept. of Physics and Astronomy                                                  
University of Victoria                                                          
Victoria, BC, CANADA,  V8W 3P6                                                  
Internet: cosmos@uvvm.uvic.ca                                                   
\endauthors                                                                     
                                                                                
\references                                                                     

                                                                                
Balam, D.D., 1996, {\it IAU Circular}, No.\,6325                                       

Christian, C.A., Adams, M., Barnes, J.V., Butcher, H., Hayes, D.S.,
 Mould, J.R., and Siegel, M., 1985, {\it PASP}, {\bf 97}, 363
                                                                                

Garnavich, P., Reiss, A., and Kirshner, R., 1996, {\it IAU Circular}, No.\,6317         

Jedrzejewski, R.I., 1987, {\it MNRAS}, {\bf 226}, 727

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\centerline{4}
\vskip 1mm


Jenkner, H., Lasker, B. M., Sturch, C.R., McLean, B.J., Shara, M.M.,
 and Russell, J.L., 1990, {\it AJ}, {\bf 99}, 2082


Koranyi, D., 1996, {\it IAU Circular}, No.\,6317


Lasker, B.M., Sturch, C.R., Lopez, C., Mallama, A.D., McLaughlin, S.F.,
 Russell, J.L., Wisniewski, W.Z., Gillespie, B.A., Jenkner, H.,
 Siciliano, E.D., Kenny, D., Baumert, J.H., Goldberg, A.M., Henry, G.W.,
 Kemper, E., and Siegel, M.J., 1988, {\it Ap. J. Suppl.}, {\bf 68}, 1


Leibundgut, B., 1988, PhD Thesis, Basel                                         
                                                                                

Mueller, J., 1996, {\it IAU Circular}, No.\,6317                                        

Sicoli, P., 1996, {\it IAU Circular}, No.\,6325                                         

Tatum, J. B., Balam, D. D., and Aikman, G. C. L., 1994, {\it Planet. Space Sci.},     
{\bf 42}, 611                                                                
                                                                                
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