Characterizing bar structures : application to NGC 1300 , NGC 7479 and NGC 7723

Detailed surface photometry has been carried out for three barred galaxies with use of high resolution CCD broadband images in the B, V and I bands. Using azimuthal luminosity profiles and their decomposition into Fourier Series, the structural parameters (length and strength) of the bars in the three galaxies have been obtained. We have also inferred the corotation radii (CR) using information available in the B − I and B−V colour index profiles. The regions selected for the CR were the ends of the bars, or a little further out and with an older stellar population than the su rrounding regions. The resulting values, RCR ∼ 100′′±10′′ for NGC 1300, RCR ∼ 63′′ for NGC 7479 and RCR ∼ 23′′ for NGC 7723, are in agreement with those previously reported in the literature. This demonstrates the utility of accurate photometry for this type of observation.