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Дата изменения: Wed Apr 14 14:21:18 1999 Дата индексирования: Sat Sep 11 20:32:02 2010 Кодировка: Поисковые слова: флуоресценция |
Altogether we have observed 209 objects preselected as ELG candidates on
HQS objective prism plates, of which 196 had no previous spectroscopic
information.
134 (64 %) are found to be either ELGs, or quasars. Of 128 detected ELGs
108 were classified on the character of their spectra and their absolute
magnitudes as BCGs or probable BCGs.
One galaxy showing broad H
(FWHM = 1800 kms-1) and H
(FWHM = 1400 kms-1) and wide and strong He II
4686
(I(He II)/I(H
)
0.7) is a Seyfert galaxy (HS 1057+4632).
One very faint object (HS 0811+4913) of absolute
magnitude M
B= -11.4 is probably a super-association
in the dwarf spiral NGC 2541.
Two galaxies show emission line ratios characteristic for LINERs.
Two are difficult to classify. The remaining 14 ELGs are objects of lower
excitation: either Starburst Nuclei galaxies (SBN) or their lower mass
analogs Dwarf Amorphous Nuclear Starburst galaxies (DANS)
(Salzer et al. [1989]).
Since the main goal of the HSS is an efficient search for new BCGs,
the fraction of this type among all new detected ELGs - 84 %,
or 80 % among all emission-line objects, is very encouraging.
It is worth to note that after the analysis of the results of pilot part of the HSS (see Paper I), the selection algorithm was improved in order to clean the candidate lists for follow-up spectroscopy from the majority of stellar-like and second priority objects. The majority of the former have been found as blue stars, and the latter are either low excitation ELG or galaxies without emission lines. The overall detection efficiency of emission-line objects has grown significantly, up to 64 % for this second part of the HSS.
The distributions of the new HSS ELGs in the line-ratio diagrams
[O III]5007/H
versus
[N II]
6583/H
and
[O III]
5007/H
versus
[O II]
3727/[O III]
5007
(see Baldwin et al. ([1981]), Veilleux & Osterbrock
([1987]) for details) in general are similar to those shown
in Paper I.
Several new high excitation BCGs are discovered or rediscovered.
Follow-up spectroscopy with high signal-to-noise of these prominent
galaxies resulted in the discovery of new very metal-poor galaxies.
This data will appear in separate papers currently in preparation.
One more immediate conclusion comes from the absolute magnitudes of
new the ELGs in Table 2. Even with some
reservations concerning the accuracy of the apparent
magnitudes, the Hamburg/SAO Survey picks up well
objects with M
.
Thus, with additional photometry to improve the accuracy of B-magnitudes,
this sample will serve as an important instrument to study the still
poorly known faint end of the ELG luminosity function.
Altogether in Paper I and in the present paper we discovered 176 new
emission-line objects (10 of them QSOs), and for 32 more galaxies we got
quantitative data for their emission lines. Preliminary
classification of the 198 ELGs yields 155 confident or probable blue
compact/low-mass H II-galaxies. Thus a large fraction of BCGs relative
to all ELGs is found ( 78 %) demonstrating the high efficiency of
this survey to find on the Hamburg Quasar Survey photoplates namely
galaxies with H II-type spectra. A statistical analysis of
this BCG sample,
supplemented with galaxies from the next parts of the survey is underway.