Kinematics of Haro 11: The miniature Antennae
Journal article, 2015

Luminous blue compact galaxies are among the most active galaxies in the local Universe in terms of their star formation rate per unit mass. They are rare at the current cosmic epoch, but were more abundant in the past and may be seen as the local analogues of higher red shift Lyman break galaxies. Studies of their kinematics is key to understanding what triggers their unusually active star formation. In this work, we investigate the kinematics of stars and ionised gas in Haro 11, one of the most luminous blue compact galaxies in the local Universe. Previous works have indicated that many of these galaxies may be triggered by galaxy mergers. We have employed Fabry-Perot interferometry, long-slit spectroscopy, and integral field unit (IFU) spectroscopy to explore the kinematics of Haro 11. We target the near-infrared calcium triplet, and use cross-correlation and penalised pixel fitting techniques to derive the stellar velocity field and velocity dispersion. We analyse ionised gas through emission lines from hydrogen, [O III], and [S III]. When spectral resolution and signal to noise allows, we investigate the line profile in detail and identify multiple velocity components when present. The spectra reveal a complex velocity field whose components, both stellar and gaseous, we attempt to disentangle. We find that to first order, the velocity field and velocity dispersions derived from stars and ionised gas agree. Hence the complexities reveal real dynamical disturbances providing further evidence for a merger in Haro 11. Through decomposition of emission lines, we find evidence for kinematically distinct components, for instance, a tidal arm. The ionised gas velocity field can be traced to large galactocentric radii, and shows significant velocity dispersion even far out in the halo. If interpreted as virial motions, this indicates that Haro 11 may have a mass of similar to 10(11) M-circle dot. Haro 11 shows many resemblances with the famous Antennae galaxies both morphologically and kinematically, but it is much denser, which is the likely explanation for the higher star formation efficiency in Haro 11.

Lyman-Break Galaxies

Haro 11

Velocity-Fields

Forming Galaxies

Ultraviolet-Luminous

Far-Ultraviolet

Massive Star-Clusters

interactions

Multiband Surface Photometry

kinematics and dynamics

X-Ray Observations

Stellar Dynamics

Alpha

galaxies evolution

Blue Compact Galaxies

Galaxies

Author

G. Östlin

Stockholm University

T. Marquart

Stockholm University

Uppsala University

Robert Cumming

Chalmers, Earth and Space Sciences, Onsala Space Observatory

K. Fathi

Stockholm University

N. Bergvall

Uppsala University

A. Adamo

Stockholm University

P. Amram

Laboratoire d'Astrophysique de Marseille

M. Hayes

Stockholm University

Astronomy and Astrophysics

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

Vol. 583 A55- A55

Subject Categories

Astronomy, Astrophysics and Cosmology

DOI

10.1051/0004-6361/201323233

More information

Latest update

4/5/2022 7