THE LIGHT CURVES OF TYPE Ia SUPERNOVA 2004fu

CCD UBV RI photometry is presented for type Ia supernova 2004fu in NGC 6949. The light and colour curves are typical for this class of objects, absolute magnitude at maximum and decline rate are in agreement with the relationship between these parameters, established for SNe Ia. SN 2004fu was discovered by Arbour (2004) on unfiltered CCD images taken with a 0.3-m Schmidt-Cassegrain reflector on November 4.87 (at mag approximately 16.8) and 5.81 (mag approximately 16.5). The new object was located at α = 203511.54, δ = +644825.7 (equinox 2000.0), which is 29 east and 15 north of the center of the Sc galaxy NGC 6949. Modjaz et al. (2004) report that a spectrum (range 350-740 nm) of SN 2004fu, obtained on November 10.17 UT with the F. L. Whipple Observatory 1.5-m telescope, shows it to be a type-Ia supernova, several days before maximum light. We started photometric observations of SN 2004fu immediately after discovery, on November 6, with 60-cm reflector of Crimean Observatory of Sternberg Astronomical Institute (C60) equipped with Roper Scientific VersArray1300B CCD camera, and continued monitoring nearly each night until November 25. On November 22 images were obtained at 38-cm reflector of Crimean Astrophysical Observatory (C38) with Apogee AP-47p CCD camera. From 2004 December 29 until 2005 March 26 we observed SN 2004fu on four nights at 70-cm reflector in Moscow (M70) with AP-47p CCD camera, and on 2005 May 4 last images were obtained at C60. The reductions and photometric techniques were described by Tsvetkov (2006) and Tsvetkov et al. (2006). The image of SN 2004fu with comparison stars is shown in Fig. 1. Supernova is far away form the center of the galaxy and from the spiral arms, and the galaxy background does not affect the measurements. The magnitudes of the comparison stars are presented in Table 1, and photometry of SN is reported in Table 2. The light curves are shown in Fig. 2, where we also plotted the data obtained by amateur observers in the BV R bands reported at SNWeb. Their data in B are in good agreement with our results, while in the V and R bands some systematic differences can be found. We achieved excellent photometric coverage on premaximum rise and first few days of brightness decline, but later only sporadic observations were obtained. We can derive dates and magnitudes of maximum light: Bmax = 15.87 on JD 2453326.3 http://www.astrosurf.com/snweb2/2004/04fu/04fuMeas.htm