Issue |
A&A
Volume 449, Number 3, April III 2006
|
|
---|---|---|
Page(s) | 997 - 1017 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20053119 | |
Published online | 24 March 2006 |
Star formation and stellar populations in the Wolf-Rayet(?) luminous compact blue galaxy IRAS 08339+6517
Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain e-mail: angelrls@iac.es
Received:
23
March
2005
Accepted:
28
November
2005
Aims.IRAS 08339+6517 is a luminous infrared and Lyα-emitting starburst galaxy that possesses a dwarf
companion object at a projected distance of 56 kpc. An tidal tail has recently been detected between both
galaxies, suggesting that about 70% of the neutral gas has been ejected from them.Methods.We present deep broad-band optical images, together with narrow band Hα CCD images, and optical
intermediate-resolution spectroscopy of both galaxies.Results.The images reveal interaction features between both systems and strong Hα emission in the inner part of
IRAS 08339+6517. The chemical composition of the ionized gas of the galaxies is rather similar. The analysis of their
kinematics also indicates interaction features and reveals an object that could be a candidate tidal dwarf galaxy or
a remnant of an earlier merger. Our data suggest that the
tail has been mainly formed from material
stripped from the main galaxy. We find weak spectral features that could be attributed to the presence of Wolf-Rayet
stars in this starburst galaxy and estimate an age of the most recent burst of around
4–6 Myr. A more evolved
underlying stellar population, with a minimal age between 100–200 Myr, is also detected and fits an exponential
intensity profile. A model which combines 85% young and 15% old populations can explain both the spectral energy
distribution and the
Balmer and
absorption lines presented in our spectrum. The star formation
rate of the galaxy is consistently derived using several calibrations, giving a value of ~9.5
yr-1.Conclusions.IRAS 08339+6517 does satisfy the criteria of a luminous compact blue galaxy, rare objects in the local universe
but common at high redshifts, being a very interesting target for detailed studies of galaxy evolution and
formation.
© ESO, 2006
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