Distance to the Dorado Group

Abstract—Based on the archival images from the Hubble Space Telescope, we performed the photometry of the brightest galaxies of the Dorado group: NGC 1433, NGC 1533, NGC 1566, and NGC 1672. In the obtained CM-diagrams, red giants are specified, and distances to galaxies are measured by the TRGB method. The estimates obtained: 14.2 ± 1.2, 15.1 ± 0.9, 14.9 ± 1.0, and 15.9 ± 0.9 Mpc show that all the galaxies mentioned are located at approximately similar distances and form a scattered group with the average distance D = 15.0 Mpc. In the lenticular galaxy NGC 1533, it was found that blue and red supergiants form a ring structure at a distance of 3.6 kpc from the center, and are also visible in the hydrogen arm between the galaxy NGC 1533 and the dwarf IC 2038. High metallicity of these stars (Z = 0.02) indicates their origin from the gas of NGC 1533.