Walter K. Huchtmeier , Matthias Ehle , PASA, 16 (1), in press.
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Discussion
Most of the observed HI-profiles (of the whole sample) are narrow (13.5 kms-1 for the narrowest line) which is typical for dwarf galaxies (slow rotation). From the distribution of radial velocities of the detected galaxies within our sample we derive that most of these galaxies are within the Local Supercluster, about 25% of the detected galaxies are within the Local Volume. There are only a few low surface brightness (LSB) background objects. Typical global values for the galaxies in the Local Volume are fainter or equal to an absolute B magnitude of -15, linear diameter of 1.5 kpc, average HI mass of 5
, and a total mass of 6
(the typical corrected linewidth being of the order of 50 kms-1).
The correlation between linear optical diameter in kpc (at the D25 level, de Vaucouleurs et al. 1976) and the total HI mass for the whole sample is the same as observed for the Kraan-Korteweg-Tammann sample (Kraan-Korteweg and Tammann 1979, for the HI observations e.g. Huchtmeier and Richter 1988). The same is true for the correlation between HI mass and total mass.
In nearly all cases the HI distribution is centered on the optical position of the galaxy. However, lower contours of the HI distribution often show asymmetric shapes (see Fig.2) and two galaxies are definitely disturbed in the HI distribution and/or the velocity field. On average the HI distribution is larger than the optical extent (D25) by a factor of 3.
The upper limits of MHI/LB in Fig.3 are more or less close to our sensitivity limit except one very low value which corresponds to AM1012-443. There is an HI detection for AM1013-394 at a radial velocity of 263 kms-1 (Mathewson et al. 1995) with a flux of 2 Jy kms-1 which we probably did not see due to our sensitivity limit. Their other HI line for this source has a radial velocity of 2982 kms-1 which happened to lie at the edge of the bandpass of our observations and was not further considered.
Since the first compilation of galaxies in the LV in 1979 by Kraan-Korteweg and Tammann the number of known galaxies increased from 179 to 303 galaxies (Karachentsev 1998, priv. comm.). This search for nearby dwarf galaxies - the first part of which is presented here - is expected to further increase this number.
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