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Description
We present BVRI CCD photometry of ~600 stars in the central region of a resolved spiral galaxy NGC 1560 which is seen almost edge-on, apparently located in the IC 342 group. The V-(B-V) diagram shows a dominant group of significantly reddened blue plume stars consisting of young massive main-sequence and evolved blue supergiant stars. The tip of the blue plume is found to be at V~21 mag and (B-V)~0.4mag. The I-(R-I) diagram shows a large group of red supergiants the brightest of which are extending to I~19.5mag at (R-I)~1.1mag. The logarithmic slope of the V luminosity function of the blue plume stars is 0.69+/-0.10, similar to that for other nearby galaxies. The mean color of the blue plume stars is <(B-V)>=0.25+/-0.03mag. The total reddening, including both foreground and internal reddening, is estimated from the mean color of the blue plume stars, to be E(B-V)=0.40+/-0.10mag, whereas the foreground reddening based on the H I column density and faint galaxy counts is E(B-V)=0.16mag. Combining our results with those in the literature, we have obtained distance estimates using four methods: brightest blue stars [(m-M)_0_=27.11mag], brightest red stars [(m-M)_0_=27.02mag], B-band Tully-Fisher relation [(m-M)_0_=26.96mag], and H-band Tully-Fisher relation [(m-M)_0_=26.86mag]. These four estimates agree very well. Taking the average of these four estimates, we obtain a value for the true distance modulus to NGC 1560, (m-M)_0_=27.0+/-0.1mag, corresponding to a distance of 2.5+/-0.1Mpc.
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