The KMOS Redshift One Spectroscopic Survey (KROSS): The Tully-Fisher Relation of Galaxies at z~1
Witnessing Disc Galaxy Evolution Through The Eyes of their Stellar Structures
Alfred Tiley
University of Oxford
Martin Bureau (University of Oxford (O)), Richard Bower (Durham University (D)), John Stott (O), Mark Swinbank (D), Andy Bunker (O), Matt Jarvis (O), Georgios Magdis (O), Ian Smail (D), Ray Sharples (D), Helen Johnson (D), Chris Harrison (D)
The KMOS Redshift One Spectroscopic Survey (KROSS), using the K-band Multi-Object Spectrograph (KMOS) at the Very Large Telescope (VLT), aims to study the spatially-resolved dynamics, star formation properties and metallicities of ~1000 star-forming galaxies at z~1.

At z~1, we begin to probe the epoch of peak star formation in the universe, a key era for galaxy mass assembly. The primary causes of this increased star formation are hotly debated, as are the dominant mechanisms for mass growth (e.g. major mergers, secular evolution with gas accretion). It is thus essential to constrain how the ratio of stellar, gaseous and dark mass in galaxies has varied over cosmic time, and determine whether this is related to the global fall of star formation activity with decreasing look-back time since z~1-3.

Using modelling of the spatially-resolved Ha kinematics to measure dynamical masses, and SED fitting to retrieve stellar masses, we present the observed and baryonic Tully-Fisher relations (TFRs) of the ~400 KROSS galaxies observed. We explore reasons for the increased intrinsic scatter found in all relations in comparison to z~0. Considering only rotationally supported galaxies, the slopes of the TFRs generally agree with low redshift comparison samples. However, there is an apparent evolution of the offset of the TFR over the last 7 Gyrs (-1.7 mag and +0.81 dex for the H-band and stellar mass TFR respectively since z=1) i.e. for a given dynamical mass, galaxies had less stellar mass at z~1 than today. The implications of this for galaxy evolution theory are discussed.
13:30 - 15:00