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Дата изменения: Sat Jan 10 17:37:56 1998
Дата индексирования: Sat Sep 11 20:37:07 2010
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Поисковые слова: m 45

The main observational parameters

The structure of the tables is as follows:

Table 2. Column 1 gives the object name from the Case or Markarian catalogs. Columns 2 and 3 give right ascension and declination on the epoch 1950.0 according to the original Case and Markarian catalogs. The coordinates for the Case catalog objects were obtained by the Catalog's authors from the objective-prism plates of Case survey. The estimated accuracy (r.m.s.) for $\alpha$ lies within $\pm$ 3'', for $\delta$ within $\pm$ 6'' (Pesch & Sanduleak [1983]). For Markarian galaxies the errors of coordinates usually lie inside 2'' (Lipovetsky [1983]).

Column 4 gives the eye-estimated apparent blue magnitudes according to the same sources.

The apparent magnitudes for Case catalog objects are eye-estimated from the objective-prism plates as the density of the continuum near 4500 Å. As was shown by Salzer et al. ([1995]) the mean difference between Case magnitudes m_CG and m_B is m_B = m_CG + 0.25, while the scatter about the mean is $\sigma_{m_B} \sim 0.6$.We present here the original CG magnitudes in order not to mix the CG magnitude values which were derived in the same homogenious manner with the m_B estimates and measurements for small part of galaxies given in variuos sources.

For the Markarian galaxies apparent photographic magnitudes (m_pg) were taken from the Zwicky catalog (Zwicky et al. 1961-1968).

Column 5 gives heliocentric velocity as determined from our spectra. Less accurate entries are marked by colon. In section 5.3 we discuss the estimate of errors of heliocentric velocities which follow from comparison with the data from CfA catalog (Huchra et al. [1995]) and which have rms about 100 km s^-1.

In column 6 we present the estimates of the absolute blue magnitudes not corrected for the Galaxy extinction, which are derived from the heliocentric velocities of the column 5.

Other names of a galaxy we give in column 7.

Table 3 contains the spectral information for the galaxies from Table 2. In column 1 we give the same name as in column 1 of Table 2. By asterisk before the object name we mark the objects for which the spectra were obtained with AIP CCD detector. They are in general of better quality. In column 2 we give IAU-type name of the galaxy in order of quick and comfortable reference to the same object in Table 2.

In column 3 we cite the original emission-line code of the galaxy for the strength of [OIII] doublet according to the Case catalog (s - strong, m - medium, w - weak). In columns 4 and 5 we give the uncorrected for internal and Galaxy extinction flux ratios of [OII] $\lambda$3727/H$\beta$ and [OIII] $\lambda$5007/H$\beta$, respectively. The Galaxy extinction in this sky region is very low. As for the possible internal extinction, it can be significant for some of the galaxies, but for most of them due to low enough signal/noise ratio it was difficult to do flux correction. So, for homogenity all the line ratios were given only as the observed ones.

In columns 6, 7 and 8 we present equivalent widths of H$\beta$, [OII] $\lambda$3727 and [OIII] $\lambda$5007, respectively. In column 9 we make an attempt of classification similar to that of Salzer ([1989b]) for emission-line galaxies, but with lack of the firm information on the size of the galaxies. Since we use only the parameters of excitation and luminosity, some uncorrectness may be present, but we expect, that in general this classification correctly reflects the distribution of types in our sample. For the lack of good information on object sizes we joined under BCGs all the galaxies with HII-region spectrum type using Salzer's determination of BCG type as composed from HIIH, DHIIH and SS types. We separated also several galaxies as DANS type in order not to mix this small group of very low excitation dwarfs with other HII galaxies. For some of the galaxies with weaker emission in OIII lines the classification may be ambigiuous, especially for border parameters of the line strength or absolute magnitude (BCG or DANS, DANS or SBN). So we mark these objects after the suggested classification by symbol "?" to indicate the uncertainty of the suggested type.

In Table 4 we present the information about 44 galaxies where emission lines have not been detected. Either common galaxian absorption features were detected (CaII H and K, G-band, MgI) or the spectra were too noisy to extract any information besides the absence of strong emission lines. In column 1 the object name from the Case or Markarian catalogs is given. Columns 2 and 3 are the catalog's right ascension and declination on the epoch 1950.0. An apparent blue magnitude of a galaxy from the Gase or Markarian catalogs is given in column 4. In column 5 we put the heliocentric velocity determined from absorption lines. Less reliable values are marked by colons. Absolute blue magnitudes in column 6 are based on the data from columns 4 and 5. The emission-line code (strength of [OIII] $\lambda\lambda$4959,5007) as is given in the Case catalog is reproduced in column 7. In column 8 we give either the absorption features in the spectra, from which the redshift was determined, or refer to the spectra as inconclusive ones due to a quite low S/N ratio. In column 9 we give alternative names of Case galaxies, if they are already known.