In total 216 candidates were observed during the January - June, 1995, of which 33 objects were observed with the 6m telescope, 183 objects with the Calar Alto 2.2m telescope, and 4 with both instruments. Due to the schedule of the observations almost all candidates are located in the region $\alpha = 12^{\rm h} - 17^{\rm h}$ and $\delta = +45\hbox{$^\circ$}- +50\hbox{$^\circ$}$ .We find 59 new emission line galaxies, 4 quasars and 7 galaxies with absorption lines. For 11 of the known ELGs we measure emission line ratios and make quantitative classification. The remaining objects are stars or they have featureless spectra with signal-to-noise ratios insufficient to detect weak lines. The overall detection efficiency of emission-line objects (calculated after exclusion of 11 known ELGs) is rather low for this first sample, (63/205 or 30.7%). This is especially true when compared with the efficiency from Popescu et al. (1997) of about 76%, for the same photographic plates. Nevertheless, we will improve on it by including additional selection criteria, as will be discussed in Sect. 5.3.

The new emission-line galaxies are listed in Table 1, containing the following information:
Column 1: The object's IAU-type name with the prefix HS.
Columns 2 and 3: Right ascension and declination for epoch B1950. The coordinates are measured on direct plates of the HQS and are accurate to $\sim$ $2\hbox{$^{\prime\prime}$}$ (Hagen et al. 1995).
Column 4: Heliocentric velocity. Typical accuracy is between 30 and 90 km s^-1.
Column 5: Apparent B magnitude, as obtained by the calibration of the digitized photoplates (Engels et al. 1994). It has an rms accuracy of $\sim$ $0\hbox{$.\!\!^{\rm m}$}5$ for objects fainter than $m_B = 16\hbox{$.\!\!^{\rm m}$}0$ (Popescu et al. 1996). Magnitudes marked by an asterisk are taken from the APM survey (Maddox et al. 1990). Since the calibration algorithm is optimized for point sources the brightness of extended galaxies is underestimated. We expect that uncertainties of the magnitudes can be up to 2 mag (Popescu et al. 1996).
Column 6: Absolute B magnitude calculated from the apparent B magnitude and the heliocentric velocities. No correction for galactic extinction is made because all observed objects are located at high galactic latitudes and because the corrections are significantly smaller than the uncertainties of the magnitudes.
Column 7: Preliminary spectral classification type (see Sect. 4.1.1)
Column 8: Alternative names taken from the NED.

The results of line flux measurements are given in Table 2. It contains the following information:
Column 1: The object's IAU-type name with the prefix HS.
Column 2: Observed flux (in 10^-16 erg s^-1 cm^-2) of the H ${\beta}$ $\lambda$ 4861 Å line.
Columns 3, 4, 5: The observed flux ratios [OII]/H ${\beta}$ ,[OIII]/H ${\beta}$ and H $\alpha$ /H ${\beta}$ . For objects without detected H ${\beta}$ emission line, the absolute fluxes are given.
Columns 6, 7: The observed flux ratios [NII] $\lambda$ 6583 Å/H $\alpha$ , and ([SII] $\lambda$ 6716 Å + [SII] $\lambda$ 6731 Å)/H $\alpha$ .
Columns 8, 9, 10: Equivalent widths of the lines [OII] $\lambda$ 3727 Å, H ${\beta}$ and [OIII] $\lambda$ 5007 Å.

4.1.1 Classification criteria

According to VO87 a confident separation of the two ionization mechanisms and a classification of the galaxy can be obtained from its location on the [OIII] $\lambda\,5007$ Å/H ${\beta}$ versus [NII] $\lambda\,6583$ Å/H $\alpha$ diagram. This diagram has the advantage of being reddening-insensitive and is used to classify the ELGs from the Calar Alto observations which cover a wide spectral region from 3700 Å to 8100 Å.

The observations of the 12 ELGs with the 6m telescope do not cover the red region. For these objects we use the [OIII] $\lambda\,5007$ Å/H ${\beta}$ versus [OII] $\lambda\,3727$ Å/[OIII] $\lambda\,5007$ Å diagram, which is also a good constraint on the ionization mechanisms, but it is reddening-sensitive, so that extinction corrections would be desirable. However this correction is unreliable for the 6m telescope observations due to poor S/N ratios near the H $\gamma$ emission line. Nevertheless for high-excitation BCGs the average reddening is not large (Izotov et al. 1993a, 1994, 1997b), and therefore, even without extinction correction they occupy nearly the correct positions in this diagnostic diagram. For lower-excitation galaxies, however, the reddening is getting larger in average, and thus the possible uncertainty of their classification can increase, especially if an object falls into the transition area.

$\begin{figure} \psfig {figure=ds8109f4.ps,width=9.7cm} \end{figure}$

Figure 4: a, b) Classification diagrams for ELGs. The dashed line separates regions of HII-type and AGN spectra, according to VO87 and BPT81. The dotted lines separate the region in which high $T_{\rm eff}$ star excitation takes place from the region of low ionization populated by DANS and SBN (after S89a)

In Fig. 4 emission-line galaxies from the HSS sample are plotted in comparison with some BCGs from the SBS (Izotov et al. 1994, 1997b; Thuan et al. 1995) and ELGs from the Case survey (Weistrop & Downes 1988, 1991; Augarde et al. 1987; Salzer et al. 1995; Ugryumov et al. 1998). The branch of HII-galaxies is separated from AGN by a short-dashed line running in both figures from the left-top corners populated by objects showing strong emission lines to the right-bottom corners populated by objects with a low level of gas ionization.

It is clear from the data in Fig. 4 that the major part of the observed HSS emission-line galaxies belongs to HII-galaxies and only a few objects can be classified as probable AGN.

From the two objects in the AGN region of Fig. 4a only one -- HS 1609+4902 -- can be definitely classified in both diagrams as a Sy2 galaxy. The second probable AGN-type object is HS 1304+4710. In Fig. 4a it is located not too far from the border line separating HII-type objects from AGNs. We tentatively classify it as a possible LINER (low-ionization nuclear emission-line region galaxies; Heckman 1980). In Fig. 4b this object falls however within the HII-type region. A possible reason for this is the reddenning due to the dust extinction.

Among the second priority candidates we find a number of low-excitation massive galaxies with nondetected (in low S/N spectra) H ${\beta}$ and [OIII] $\lambda\,5007$ Å emission lines. They are tentatively classified as possible LINERs (marked as LINER? in Table 1) according to the flux ratios of [NII] $\lambda\,6583$ Å and H $\alpha$ (Heckman 1980). Although these galaxies are not shown in Fig. 4, they, likely, populate the extreme right-bottom corner in Fig. 4a.

We use some additional criteria for the classification of ELGs in the cases where the S/N ratio is insufficient to use the diagnostic diagrams. As it was emphasized by Salzer (1989a, hereafter S89a) there is a tight correlation between the ELG type and their mean global parameters such as luminosity and size. In particular, the ELGs with the highest excitation are low-luminosity, compact objects, while AGN-type objects are almost always high-luminosity, large galaxies.

Two more objects in Fig. 4b, HS 1038+4616 and HS 1443+5018, fall into AGN region. We suspect that it is due to poor S/N ratio for H ${\beta}$ . Therefore, their large [OIII] $\lambda\,5007$ Å/H ${\beta}$ ratios are unreliable, and, probably these galaxies are low excitation BCGs. Indeed, their low luminosities ( $M_B = -17\hbox{$.\!\!^{\rm m}$}2$ and $-17\hbox{$.\!\!^{\rm m}$}1$ , respectively) are more compatible with a HII-type nature.

HII-galaxies can be splitted further into several classes depending on physical parameters such as sizes, absolute magnitudes, colors, metal abundance, equivalent widths (EW) of the [OIII] $\lambda$ 5007 Å line and morphology. S89a have proposed the following sequence of HII-galaxy types (starting with the least luminous and most compact objects and ending with the most luminous, quite large spirals): "Sargent-Searle (SS) objects'' (or "Blue Compact Dwarfs (BCD)''), "dwarf HII hotspot (DHIIH) galaxies'', "HII hotspot (HIIH) galaxies'', "Dwarf Amorphous Nucleus Starburst (DANS) galaxies'' and "Starburst Nucleus (SBN) galaxies''. There is also a significant correlation of the luminosity with other parameters, such as metallicity, EW of the [OIII] $\lambda$ 5007 Å line and color.

The insufficient quality of our spectroscopy does not allow to perform such detailed classification. Therefore, in our case SS, DHIIH and HIIH galaxies are taken together as one class of blue compact/HII galaxies (BCGs), which are objects with strong and moderate emission lines, caused by the large number of young OB-stars in current burst of star formation.

Following S89a, we separate the BCGs and low-excitation ELGs regions in the diagnostic diagrams with dotted lines (Fig. 4). This border is derived from the analysis and generalization of good-quality ELG observational data from the UM survey. To classify objects near the border we use additional parameters, such as EW([OIII] $\lambda$ 5007 Å) and M_B, according to their characteristic values for corresponding ELGs from S89a.

4.1.2 Selection effects

The main ELG candidate selection criteria applied here are a blue continuum (near $\lambda$ 4000 Å) and the presence of strong or moderate [OIII] $\lambda\lambda$ 4959, 5007 Å emission lines recognized in digitized prism spectra with magnitudes in the range B = $16\hbox{$.\!\!^{\rm m}$}0 - 19\hbox{$.\!\!^{\rm m}$}5$ . Figure 5 shows the equivalent widths of the [OIII] $\lambda$ 5007 Å line versus the apparent and absolute blue magnitudes. It is evident from Fig. 5a that the detection limit of the HSS for BCGs based on this strongest emission line is EW([OIII] $\lambda$ 5007 Å) $\le$ 15 Å. There is a clear trend of increase of equivalent widths (EW) with apparent magnitude, and even more noticeable anticorrelation between EWs and absolute magnitudes, if not only BCGs but all ELGs are taken into account. Similar trends were noticed for the UM ELGs by Salzer et al. (1989a,b).

$\begin{figure} \psfig {figure=ds8109f5.ps,width=10.0cm,angle=0} \end{figure}$

Figure 5: a, b) Logarithm of the equivalent width of [OIII] $\lambda$ 5007 Å emission line versus blue apparent a) and absolute magnitudes b) for HSS ELGs. BCG are plotted as filled circles and other types as empty circles. The solid line joins averages of equivalent widths taken over 1 mag apparent magnitude intervals a) and over 2 mag absolute magnitude intervals b)

In analogy to the UM ELGs, the anticorrelation evident in Fig. 5b is caused by two effects. First, because of the brightness limit imposed by the plates we miss low-luminosity ELGs with weak emission lines. The galaxies would populate the lower left corner of the Fig. 5b. Second, the region of avoidance in the upper right corner is most likely caused by metallicity effects. In general HII-regions in bright galaxies have larger heavy element abundance, and, therefore, they are cooler with lower EW([OIII] $\lambda$ 5007 Å).

4.2 Quasars

QSOs with strong emission lines might be selected in our sample if either the Ly $\alpha$ $\lambda$ 1216 Å line redshifted to $z \sim 3$ or the MgII $\lambda$ 2798 Å line redshifted to $z \sim 0.9$ appear in the wavelength region between 5000 Å and the sensitivity break of the Kodak IIIa-J photoemulsion near 5400 Å. This produces an easily visible emission peak on the digitized prism spectra even for very faint objects (B $\sim 19\hbox{$.\!\!^{\rm m}$}0 - 20\hbox{$.\!\!^{\rm m}$}0$ ) which is usually hard to distinguish from low-redshifted [OIII] features.

Both kinds of QSOs are present in our sample (Table 3): HS 1313+4651 with $z \sim 3$ , and HS 1446+4611 and HS 1300+4835 with $z \sim 0.8$ . The fourth QSO (HS 1040+4904) might have been a distant ELG because the feature visible in the objective prism spectrum was thought to be [OII] $\lambda$ 3727 Å emission line shifted to a wavelength near 4000 Å. However, the slit spectrum suggests that an identification with MgII $\lambda$ 2798 Å emission line at $z \sim 0.5$ is more likely.

4.3 Objects without emission lines

4.3.1 Absorption-line galaxies

The signal-to-noise ratio of spectra for seven bright non-ELG galaxies is sufficient to detect absorption lines, allowing the determination of redshifts. These galaxies are listed in Table 4.

Taking into account a probable underestimation of their apparent brightnesses by 1 magnitude, they are (with one exception) quite luminous, with M_B in the range $-19\hbox{$.\!\!^{\rm m}$}0$ to $-20\hbox{$.\!\!^{\rm m}$}5$ . Most of them have noticeable H ${\beta}$ and H $\gamma$ absorption and so they are probably post-starburst galaxies.

4.3.2 Stellar objects

To separate stellar spectra from other non emission-line spectra we use a template with the most common stellar features which is cross-correlated with the observed spectra. We found 111 objects with definite stellar spectra. Six of them are obvious M-stars. The remaining stellar spectra are roughly classified as A - G stars, most of them having intermediate types between A and F, or F and G. The coordinates, apparent magnitudes, spectral types and lists of absorption features identified in the spectra of these objects are given in Table 5.

4.3.3 Non-classified objects

The spectra of 24 objects show neither emission nor absorption features and, therefore, cannot be classified. We divide them into three categories according to the slope of their continuum in the range between 4000 and 5000 Å. Six objects (25%) have "blue'' spectra ( $\alpha(4000-5500) \leq -0.2$ ), 10 objects (42%) have "flat'' spectra ( $-0.2 \le \alpha(4000-5000) \le +0.2$ ) and 8 objects (33%) are "red'' objects ( $\alpha(4000-5000) \geq +0.2$ ). Thus, if these non-classified objects are stars, most of them are rather hot.

One of the non-classified objects observed with the 6m telescope (HS 1517+4021) has a quite strange spectrum in the range 3700-5500 Å, indicating a possible composite system. On the DSS (Digital Sky Survey) we find an indication of a close faint companion star, which could have entered into IPCS circular aperture.

4 Results of follow-up spectroscopy