Spectroscopic VIMOS/IFU observations are presented for three galaxies known to host two stellar counter-rotating discs of comparable sizes. For the first time both the kinematics and stellar population properties of the two counter-rotating discs in the observed galaxies were separated and measured. The secondary, less massive, stellar component rotates in the same direction as the ionised gas and is on average younger and less metal-rich than the main galaxy disc. These results support the scenario of gas accretion followed by star formation as the origin for large counter-rotating stellar discs in galaxies, and set an upper limit of 44% to those formed by binary galaxy mergers.
Disentangling the kinematics and stellar populations of counter-rotating stellar discs in galaxies
MORELLI, LORENZO;PIZZELLA, ALESSANDRO;CORSINI, ENRICO MARIA;DALLA BONTA', ELENA
2013
Abstract
Spectroscopic VIMOS/IFU observations are presented for three galaxies known to host two stellar counter-rotating discs of comparable sizes. For the first time both the kinematics and stellar population properties of the two counter-rotating discs in the observed galaxies were separated and measured. The secondary, less massive, stellar component rotates in the same direction as the ionised gas and is on average younger and less metal-rich than the main galaxy disc. These results support the scenario of gas accretion followed by star formation as the origin for large counter-rotating stellar discs in galaxies, and set an upper limit of 44% to those formed by binary galaxy mergers.
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