Unravelling the origin of the counter-rotating core in IC 1459 with KMOS
Galaxy structure in the low-redshift universe
Laura Prichard
University of Oxford
R. L. Davies (Oxford), R. C. W. Houghton(Oxford), J. P. Stott (Oxford)
IC 1459 is the archetype of a massive early-type galaxy (ETG) with a rapidly counter-rotating core. Understanding the origins of kinematically distinct populations in individual galaxies will allow us to shed light on the formation processes of ETGs. We present new NIR integral field spectroscopic data from the K-band Multi-Object Spectrograph (KMOS) on the VLT. By combining the 24 integral field units of KMOS, we generate over 45,000 spectra spanning this bright galaxy, allowing us to study IC1459 in unparalleled detail. We use this data to trace the kinematics and study the stellar populations of IC 1459 to better understand the origin of the counter-rotating core. We study dwarf-sensitive absorption features to investigate the initial mass functions of the distinct components. We also find that the co-rotating stars and gas in the core feature a striking asymmetric velocity dispersion. Combining these results, we conclude this is strong evidence that the counter-rotating core is the result of the accretion of a gas rich system, which likely triggered a starburst event in the centre.


09:00 - 10:30
BS - Lecture Theatre A25 (121)