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The KMOS Redshift One Spectroscopic Survey (KROSS): the Tully-Fisher relation at z~1

A. L. Tiley, J. P. Stott, A. M. Swinbank, M. Bureau, C. M. Harrison, R. Bowen, H. L. Johnson, A. J. Bunker, M. Jarvis, G. Magdis, R. M. Sharples, I. Smail, D. Sobral, P. Best

Abstract
We present the stellar mass (M*), and K-corrected K-band absolute magnitude (MK) Tully-Fisher relations (TFRs) for subsamples of the 584 galaxies spatially resolved in H α emission by the KMOS Redshift One Spectroscopic Survey (KROSS). We model the velocity field of each of the KROSS galaxies and extract a rotation velocity, V80 at a radius equal to the major axis of an ellipse containing 80 per cent of the total integrated H α flux. The large sample size of KROSS allowed us to select 210 galaxies with well-measured rotation speeds. We extract from this sample a further 56 galaxies that are rotationally supported, using the stringent criterion V80/σ 〉 3, where σ is the flux weighted average velocity dispersion. We find the MK and M* TFRs for this subsample to be MK / {mag}= (-7.3 ± 0.9) × [(log (V_{80}/{km s^{-1}})-2.25]- 23.4 ± 0.2, and log (M_{{ast }} / M_{{☉}})= (4.7 ± 0.4) × [(log (V_{80}/{km s^{-1}}) - 2.25] + 10.0 ± 0.3, respectively. We find an evolution of the M* TFR zero-point of -0.41 ± 0.08 dex over the last ̃8 billion years. However, we measure no evolution in the MK TFR zero-point over the same period. We conclude that rotationally supported galaxies of a given dynamical mass had less stellar mass at z ̃ 1 than the present day, yet emitted the same amounts of K-band light. The ability of KROSS to differentiate, using integral field spectroscopy with KMOS, between those galaxies that are rotationally supported and those that are not explains why our findings are at odds with previous studies without the same capabilities.

Keywords
galaxies: evolution, galaxies: general, galaxies: kinematics and dynamics

Monthly Notices of the Royal Astronomical Society
Volume 460, Issue 1, Page 103
2016 April

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Instituto de Astrofísica e Ciências do Espaço Universidade do Porto Faculdade de Ciências da Universidade de Lisboa Fundação para a Ciência e a Tecnologia
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