Determination of Rotation Curves and Study of Galaxy Evolution Based on the KMOS 3D Survey at Redshifts 0.7 < z < 2.7
Va Syarif, Hesti Retno Tri Wulandari

Institut Teknologi Bandung
Jalan Ganesha 10, Bandung 40132, Indonesia

Abstract

Understanding galaxy evolution is key to unraveling the formation and growth of cosmic structures. This study examines the kinematic evolution of star-forming galaxies using KMOS 3D data across redshifts -0.7 < z < 2.7-. From a final sample of 24 galaxies, rotation curves and gas velocity dispersion profiles were derived using 3D Barolo modeling of H-\alpha- data.

Most galaxies exhibit rising then flattening rotation curves, indicating dark matter dominance even at high redshift. The Stellar Mass Tully-Fisher Relation (sTFR) shows no significant evolution in intercept, though galaxies lie below the local relation, suggesting lower past stellar masses at fixed rotation velocity. A strong evolution in intrinsic gas velocity dispersion (-\sigma_{gas}-) is observed, increasing from -\sim-14-24 km/s (-z<1-) to -\sim-40-50 km/s (-z>2-), consistent with disk settling. Dark matter fractions (-f_{DM}-) are higher at -2R_e- than at -R_e-, supporting inside-out growth with weakening radial gradients over time.

These results suggest that the basic kinematic structure of massive disk galaxies was already in place by -z \sim 2.3-, with evolution primarily in gas dynamics and stellar mass buildup.

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Topic: Galaxies and Cosmology