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arXiv · 1608.01677

The Califa and Hipass velocity function for all morphological galaxy types

S. Bekeraitė·C. J. Walcher·L. Wisotzki·D. J. Croton·J. Falcón-Barroso·M. Lyubenova·D. Obreschkow·S. F. Sánchez·K. Spekkens·P. Torrey·G. van de Ven·M. A. Zwaan·Y. Ascasibar·J. Bland-Hawthorn·R. González-Delgado·B. Husemann·R. A. Marino·M. Vogelsberger·B. Ziegler·the CALIFA collaboration
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Abstract

The velocity function is a fundamental observable statistic of the galaxy population, similarly impor- tant as the luminosity function, but much more difficult to measure. In this work we present the first directly measured circular velocity function that is representative between 60 < v_circ < 320 km/s for galaxies of all morphological types at a given rotation velocity. For the low mass galaxy population (60 < v_circ < 170 km/s), we use the HIPASS velocity function. For the massive galaxy population (170 < v_circ < 320 km/s), we use stellar circular velocities from the Calar Alto Legacy Integral Field Area Survey (CALIFA). In earlier work we obtained the measurements of circular velocity at the 80% light radius for 226 galaxies and demonstrated that the CALIFA sample can produce volume- corrected galaxy distribution functions. The CALIFA velocity function includes homogeneous velocity measurements of both late and early-type rotation-supported galaxies and has the crucial advantage of not missing gas-poor massive ellipticals that HI surveys are blind to. We show that both velocity functions can be combined in a seamless manner, as their ranges of validity overlap. The resulting observed velocity function is compared to velocity functions derived from cosmological simulations of the z = 0 galaxy population. We find that dark matter-only simulations show a strong mismatch with the observed VF. Hydrodynamic simulations fare better, but still do not fully reproduce observations.

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S. Bekeraitė, C. J. Walcher, L. Wisotzki, D. J. Croton, J. Falcón-Barroso, M. Lyubenova, D. Obreschkow, S. F. Sánchez, K. Spekkens, P. Torrey, G. van de Ven, M. A. Zwaan, Y. Ascasibar, J. Bland-Hawthorn, R. González-Delgado, B. Husemann, R. A. Marino, M. Vogelsberger, B. Ziegler, the CALIFA collaboration. 2016-08-04. The Califa and Hipass velocity function for all morphological galaxy types. https://doi.org/10.3847/2041-8205%2F827%2F2%2Fl36

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