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Дата изменения: Wed Apr 14 14:21:19 1999
Дата индексирования: Sat Sep 11 20:29:12 2010
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Поисковые слова: arp 220

Emission-line galaxies

The new emission line galaxies are listed in Table 2 containing the following information:
column 1: The object's IAU-type name with the prefix HS.
column 2: Right ascension for epoch B1950.
column 3: Declination for epoch B1950. The coordinates were measured on direct plates of the HQS and are accurate to $\sim$ 2$\arcsec$ (Hagen et al. [1995]).
column 4: Heliocentric velocity and its r.m.s. uncertainty in km s^-1.
column 5: Apparent B-magnitude obtained by calibration of digitized photoplates with photometric standard stars (Engels et al. [1994]), having an r.m.s. accuracy of $\sim$ $0\fm5$ for objects fainter than m_B = $16\fm0$ (Popescu et al. [1996]). Since the algorithm to calibrate the objective prism spectra is optimized for point sources the brightnesses of extended galaxies are underestimated. We expect that uncertainties of the magnitudes can be up to 2 mag (Popescu et al. [1996]).
column 6: Absolute B-magnitudes calculated from the apparent B-magnitude and heliocentric velocity. 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 according to the spectral data presented in this article. BCG means that the galaxy posesses a characteristic H II-region spectrum and low enough luminosity, SBN and DANS are galaxies of lower excitation with a corresponding position in line ratio diagrams, as discussed in Paper I. SBN are the brighter fraction of this type. The Seyfert galaxy shows widened H$\alpha$ and H$\beta$ and strong and widened He II$\lambda$4686 Å line. SA are probable super-associations in the outskirts of two dwarf spirals. Two objects are difficult to classify. They are coded as NON.
column 8: One or more alternative names, according to the information from NED.

The spectra of all emission-line galaxies are shown in the Appendix A.

The results of line flux measurements are given in Table 4. It contains the following information:
column 1: The object's IAU-type name with the prefix HS.
column 2: Observed flux (in 10^-16ergs^-1cm^-2) of the H$\beta$$\lambda$4861 Å line. For few objects without H$\beta$ emission line the fluxes are given for H$\alpha$ marked by an asterisk. For about 10 objects observed during non-photometric conditions this parameter is unreliable and marked by (:)
columns 3,4,5: The observed flux ratios [O II]/H$\beta$, [O III]/H$\beta$ and H$\alpha$/H$\beta$.
columns 6,7: The observed flux ratios [N II]$\lambda$6583 Å/H$\alpha$, and ([S II]$\lambda$6716 Å + [S II]$\lambda$6731 Å)/H$\alpha$.
columns 8,9,10: Equivalent widths of the lines [O II]$\lambda$3727 Å, H$\beta$ and [O III]$\lambda$5007 Å. For few objects without detected H$\beta$ emission line the equivalent widths are given for H$\alpha$ marked by an asterisk.

Below we give notes on several individual objects in Table 2.

HS0737+4011 This is a comet-like galaxy. The spectrum is shown for its head.
HS0811+4913 This is a probable super-association (SA) at 75$\arcsec$ to NEE from the nucleus of the SA(s)cd galaxy NGC 2541 (M _B = -17.5) with a radial velocity 556 kms^-1.
HS1035+4758 Nearby BCG with a recent supernovae type IIP (SN1998bv, Kniazev et al. [1998], Merlino et al. [1998], Pustilnik et al. [1999]).
HS1057+4632 KUG 1047+465 is at 67$\arcsec$ to NNE.
HS1102+4120 An object resembling on the Digital Sky Survey (DSS) an elliptical galaxy with a size $15\arcsec\times12\arcsec$ elongated NE-SW. Due to strong [S II] lines the galaxy is classified as LINER in diagnostic diagrams involving this line. But its luminosity is untypically low for a LINER. An alternative classification is therefore an H II galaxy with some enhanced [S II] shock excitation (post-merger starburst ?).
HS1457+4458AB Two ELGs with close redshifts at $\approx$20 $^{\prime\prime}$ from each other (15 kpc in projection). Interacting pair ?
HS1542+4116 Seemingly a dwarf companion of the SB(r)b galaxy NGC 5993, which is at 52$\arcsec$ to the west. This SB galaxy is a component of the pair KPG 471.
HS1604+4127 Seemingly a dwarf companion of a barred dwarf spiral CGCG 1604.0+4127 at 41$\arcsec$ to NE. The latter is a component of the galaxy pair KPG 482.
HS1614+4709 Probable companion of the face-on dwarf spiral UGC 10310$\equiv$Arp 2.
HS1643+4015 This is a disturbed galaxy of about 24$\arcsec$in extent with two knots in the central part. The spectrum is shown for the brighter eastern one.
HS1717+4955 Seemingly a dwarf companion of the SB(s)dm galaxy UGC 10806 (M _B = -17.8) with a radial velocity of $\sim$ 927 kms^-1(see for details Kniazev et al. [1999]).

Several new BCGs from this paper were reobserved with higher S/N ratio in order to measure the flux of the [O III]$\lambda$4363 line, necessary to determine unambiguously the electron temperature T_e([O III]) of the H II-region and the oxygen abundance. A preliminary determination according to the procedure decribed by Izotov et al. ([1997]) shows a log(O/H)+12 for the five most metal-deficient BCGs HS 0822+3542, HS 0837+4717, HS 1013+3809, HS 1033+4757 and HS 1442+4250 to be 7.4, 7.68, 7.63, 7.7 and 7.7, respectively. A more detailed presentation of their spectroscopy will appear in forthcoming publications.