Stellar dynamics of blue compact galaxies. II. Further indications of a merger in ESO 338-IG04
Artikel i vetenskaplig tidskrift, 2008

Context: Luminous blue compact galaxies, common at ∼ 1 but now relatively rare, show disturbed kinematics in emission lines. Aims: As part of a programme to understand their formation and evolution, we have investigated the stellar dynamics of a number of nearby objects in this class. Methods: We obtained long-slit spectra with VLT/FORS2 in the spectral region covering the near-infrared calcium triplet. In this paper we focus on the well-known luminous blue compact galaxy ESO 338-IG04(Tololo 1924-416). A previous investigation, using Fabry-Perot interferometry, showed that this galaxy has a chaotic Hαvelocity field, indicating that either the galaxy is not in dynamical equilibrium or that Hαdoes not trace the gravitational potential due to feedback from star formation. Results: Along the apparent major axis, the stellar and ionised gas velocities for the most part follow each other. The chaotic velocity field must therefore be a sign that the young stellar population in ESO 338-IG04is not in dynamical equilibrium. The most likely explanation, which is also supported by its morphology, is that the galaxy has experienced a merger and that this has triggered the current starburst. Summarising the results of our programme so far, we note that emission-line velocity fields are not always reliable tracers of stellar motions, and go on to assess the implications for kinematic studies of similar galaxies at intermediate redshift. © 2008 ESO.

Galaxies: individual: ESO 338-IG04

Galaxies: evolution

Galaxies: kinematics and dynamics

Galaxies: interactions

Galaxies: starburst

Författare

Robert Cumming

Chalmers, Institutionen för radio- och rymdvetenskap

K. Fathi

Instituto de Astrofísica de Canarias

G. Östlin

Stockholms universitet

T. Marquart

Uppsala universitet

I. Márquez

Instituto de Astrofisica de Andalucía (IAA)

J. Másegosa

Instituto de Astrofisica de Andalucía (IAA)

N. Bergvall

Uppsala universitet

P. Amram

Centre national de la recherche scientifique (CNRS)

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 479 3 725-733

Ämneskategorier

Astronomi, astrofysik och kosmologi

Fundament

Grundläggande vetenskaper

DOI

10.1051/0004-6361:20078916

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Senast uppdaterat

2023-09-18