Photometry of SN 2002bo with template image subtraction

摘要

VRI photometry of the type Ia supernova 2002bo is presented. This SN exploded in a dusty region of the host galaxy NGC 3190, thus, subtraction of a template frame was necessary to obtain reliable photometry. We used a template frame of NGC 3190 taken during the course of our galaxy imaging project, fortunately, just a few days before SN 2002bo was discovered. The aim of this project is to collect template frames of nearby galaxies that are potential hosts of bright SNe. Subtraction of pre-SN images helped us to exclude the background light contamination of the host galaxy. The maximum occurred at JD 2452346, with maximal V brightness of 13.~m58. MLCS analysis led to T_0(B) = JD 2452346.1 ± 0.8 (fiducial Bmaximum), E(B-V), = 0.~m24 ± 0~m.02, μ0 = 32.46 ± 0.06, Δ = -0.14 + 0.04. E(B-V) = 0~m.024(2) indicates a significant extinction in the host galaxy as the galactic reddening is negligible toward NGC 3190. The accepted value of Δ indicates that SN 2002bo was a slightly overluminous SN by about 0~m.14 relative to fiducial SN type Ia. The distance turned out to be 31.0 ± 3 Mpc. In addition, the heavily obscured SN 2002cv was also detected on the I frame taken on JD 2452434 (June 8, 2002), and a variable star is found in the field, very close to the host galaxy.