J/A+A/397/463 The Hamburg/SAO Survey for BCGs. I. (Ugryumov+, 2003)
The Hamburg/SAO Survey for low metallicity blue compact/HII galaxies (HSS-LM).
I. The first list of 46 strong-lined galaxies.
Ugryumov A.V., Engels D., Pustilnik S.A. Kniazev A.Y., Pramsky A.G.,
Hagen H.-J.
<Astron. Astrophys. 397, 463 (2003)>
=2003A&A...397..463U 2003A&A...397..463U
ADC_Keywords: Galaxies, peculiar ; Galaxies, photometry ; Spectroscopy ;
Radial velocities
Keywords: galaxies: dwarf - galaxies: abundances -
galaxies: distances and redshifts - surveys
Description:
We present the description and the first results of a new project
devoted to the search for extremely metal-deficient blue
compact/HII-galaxies (BCGs) and to the creation of a well selected
large BCG sample with strong emission lines. Such galaxies should be
suitable for reliable determination of their oxygen abundance through
the measurement of the faint [OIII]4363Å line. The goals of the
project are two-fold: a) to discover a significant number of new
extremely metal-poor galaxies (Z≤1/20Z☉), and b) to study the
metallicity distribution of local BCGs. Selection of candidates for
follow-up slit spectroscopy is performed on the database of objective
prism spectra of the Hamburg Quasar Survey.
The sky region is limited by δ≥0° and bII≤-30°. In
this paper we present the results of the follow-up spectroscopy
conducted with the Russian 6m telescope. The list of observed
candidates contained 52 objects, of which 46 were confirmed as
strong-lined BCGs (EW([OIII]5007≥100Å). The remaining five lower
excitation ELGs include three BCGs, and two galaxies classified as SBN
(Starburst Nucleus) and DANS (Dwarf Amorphous Nucleus Starburst). One
object is identified as a quasar with a strong Ly_alpha emission line
near λ=5000Å (z∼3). We provide a list with coordinates,
measured radial velocities, B-magnitudes, equivalent widths
EW([OIII]5007) and EW(Hβ) and for the 46 strong-lined BCGs the
derived oxygen abundances 12+log(O/H). The abundances range between
7.42 and 8.4 (corresponding to metallicities between 1/30 and
1/3Z☉). The sample contains four galaxies with Z≤1/20Z☉,
of which three are new discoveries. This demonstrates the high
efficiency of the new project to find extremely metal-deficient
galaxies. The radial velocities of the strong-lined ELGs range between
500 and 19000km/s with a median value of ∼6400km/s. The typical
B-magnitudes of the galaxies presented are 17.0mag-18.0mag.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 130 46 Parameters of the strong-lined BCGs
table3.dat 130 5 Parameters of Emission-Line Galaxies with
EW([OIII]5007)<100Å
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See also:
J/A+AS/135/511 : The Hamburg/SAO Survey for ELGs. I. (Ugryumov+ 1999)
J/A+AS/137/299 : The Hamburg/SAO Survey for ELGs. II. (Pustilnik+ 1999)
J/A+AS/142/417 : The Hamburg/SAO Survey for ELGs. III. (Hopp+, 2000)
J/A+A/366/771 : The Hamburg/SAO Survey for ELGs. IV (Kniazev+, 2001)
J/A+A/374/907 : The Hamburg/SAO Survey for ELGs. V. (Ugryumov+, 2001)
Byte-by-byte Description of file: table2.dat table3.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Galaxy name
15- 16 I2 h RAh Right ascension (J2000)
18- 19 I2 min RAm Right ascension (J2000)
21- 24 F4.1 s RAs Right ascension (J2000)
25 A1 --- DE- Declination sign
26- 27 I2 deg DEd Declination (J2000)
29- 30 I2 arcmin DEm Declination (J2000)
32- 33 I2 arcsec DEs Declination (J2000)
35- 39 I5 km/s RV Heliocentric radial velocity
41- 43 I3 km/s e_RV Error of radial velocity
46- 50 F5.2 mag Bmag Magnitude in B filter (1)
52- 55 F4.2 mag AB The extinction in Galaxy in the B-band (2)
57- 62 F6.2 mag BMAG Absolute B-magnitude (3)
64- 66 I3 0.1nm EWHb ? Equivalent width of Hβ (4861Å)
emission line
68- 71 I4 0.1nm EW5007 ? Equivalent width of [OIII]5007A
emission line
73- 76 F4.2 --- 12+log(O/H) ? The derived values of O abundance,
12+log(O/H)
77 A1 --- u_12+log(O/H) Uncertainty flag on 12+log(O/H) (4)
79-128 A50 --- Names Other names from NED
130 I1 --- Ref ? References to other sources of spectral
information (5)
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Note (1): APM magnitudes
Note (2): Extinction derived according to Schlegel et al. (1998ApJ...500..525S 1998ApJ...500..525S)
Note (3): Absolute magnitudes are calculated from the apparent ones
and the heliocentric velocities and are corrected for A_B
Note (4): The most uncertain data (∼0.2dex) are marked by a colon
Note (5): References:
1 - Popescu et al., 1996, Cat. J/A+AS/116/43
2 - Lu et al., 1993ApJS...88..383L 1993ApJS...88..383L
3 - van Zee et al., 1996AJ....112..129V 1996AJ....112..129V
4 - Eder et al., 1989ApJ...340...29E 1989ApJ...340...29E
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Acknowledgements: Dr. Simon Pustilnik
(End) Ugryumov Andrei [SAO RAS], Patricia Bauer [CDS] 02-Dec-2002