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4. Some optical and HI parameters of the galaxies

As was mentioned in introduction, the problem of the membership of galaxies in the IC 342/Maffei complex remains unresolved due to the strong absorption in this region and the lack of reliable direct estimates of distance to some of the galaxies. To judge the completeness of the present data, we collect in Table 7 (click here) some basic parameters of the galaxies around IC 342. In addition to the galaxies considered above, we include in the Table several objects whose distance and other parameters are presently known with low accuracy. In Table 7 (click here) such parameters are marked by "(:)''. For 12 galaxies, ranked according to their radial velocities, the following data are presented in Table 7 (click here):

(1) -- the galaxy name;

(2) -- the measured radial velocity (km/s) and the radial velocity reduced to the centroid of the Local Group (Karachentsev & Makarov 1996);

(3) -- the standard angular diameter (arcmin) and apparent axial ratio;

(4) -- the total blue magnitude of the galaxy and its morphological type;

(5) -- the estimated absorption correction, AB, and the galactic latitude (degrees);

(6) -- the HI line width (km/s) at a level of 50% of the line peak and the log of integrated HI flux tex2html_wrap_inline1678;

(7) -- the photometric distance modulus (mag) and the corresponding distance in Mpc; the distances estimated via radial velocity with tex2html_wrap_inline1680 are put in brackets;

(8) -- the standard linear diameter (kpc) and the absolute total magnitude corrected for inclination according to RC3;

(9) -- the total mass (inside the standard diameter) - to total luminosity, and the total HI mass - to - the total mass (in the solar units);

(10) -- notes concerning the source of the data on distance, magnitude and absorption.

The data presented in Table 7 (click here) may be useful for an analysis of the dynamical situation in the IC 342/Maffei complex of galaxies. Without going into a detailed discussion of the membership of the galaxies of the complex, we discuss here two items only.

    1. In spite of possible systematic errors in the determination of the distance to the galaxies, as well as absorption estimates, the integral parameters of the galaxies considered are in a general agreement with their morphological type. A possible exception is NGC 1569 which has an abnormally low mass-to-luminosity ratio. this peculiarity leads to a biased estimate of its distance (tex2html_wrap_inline1682) from the Tully-Fisher relation (Krismer et al. 1995).
    2. When going from normal spirals to irregular dwarfs, the standard error of distance estimate via the brightest stars remains constant, tex2html_wrap_inline1684 (Karachentsev & Tikhonov 1994). However, the accuracy of the Tully-Fisher (1977) method falls when it is applied to a dwarf galaxy whose rotation amplitude is comparable to the internal turbulent motions of its HI clouds. The problem is further amplified by the strong absorption in the Milky Way zone. Because of this, the brightest stars method has a major advantage over the Tully-Fisher relation in the region of IC 342/Maffei.

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