2003A&A...407...91G


C.D.S. - SIMBAD4 rel 1.7 - 2020.02.17CET21:01:17

2003A&A...407...91G - Astronomy and Astrophysics, volume 407, 91-104 (2003/8-3)

Spectroscopic and photometric studies of low-metallicity star-forming dwarf galaxies. II. HS 1442+4250.

GUSEVA N.G., PAPADEROS P., IZOTOV Y.I., GREEN R.F., FRICKE K.J., THUAN T.X. and NOESKE K.G.

Abstract (from CDS):

We present broad-band V and I imaging and long-slit spectroscopy in the optical range λλ3600-7500Å of the dwarf irregular galaxy HS 1442+4250. The oxygen abundance 12+log(O/H)=7.63±0.02 (Z=Z/19) in the brightest H II region of HS 1442+4250 places the galaxy among the most metal-deficient emission-line galaxies. The low metallicity and blue colour (V-I)∼0.4mag of the low-surface-brightness (LSB) component make HS 1442+4250 a likely rare young dwarf galaxy candidate. We use four methods to estimate the stellar population age in the LSB component of HS 1442+4250. Different star formation histories are considered. The equivalent widths of hydrogen Hα and Hβ emission lines, and of hydrogen Hγ and Hδ absorption lines, the spectral energy distribution and the observed (V-I) colours of the LSB regions are reproduced quite well by models with only young and intermediate-age stellar populations. By contrast, the observational data cannot be reproduced by a stellar population formed continuously with a constant star formation rate in the age range from 0 to >2Gyr. While a faint old stellar population in HS 1442+4250 with an age >2Gyr is not excluded, we find no evidence for such a population from the present data.

Abstract Copyright:

Journal keyword(s): galaxies: abundances - galaxies: dwarf - galaxies: evolution - galaxies: starburst - galaxies: stellar content

Simbad objects: 5

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Number of rows : 5

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 SBSG 0335-052 bCG 03 37 44.04 -05 02 38.5     16.65     ~ 426 1
2 Mrk 116 PaG 09 34 02.1 +55 14 25           ~ 985 1
3 LEDA 39402 H2G 12 17 17.093 -28 02 32.67   17       ~ 123 0
4 MCG+07-29-060 QSO 14 17 01.716 +43 30 13.52   15.6       ~ 148 0
5 UGC 9497 H2G 14 44 12.8032800372 +42 37 43.773570223   16.0       ~ 57 0

    Equat.    Gal    SGal    Ecl

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2020.02.17-21:01:17

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