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arXiv 1608.01677astro-ph.GA
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所有形态星系类型的Califa和Hipass速度函数

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.… 展开作者

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

摘要:

速度函数是一个基本的可观测的统计星系人口,同样重要的光度函数,但更难以测量。在这项工作中,我们提出了第一个直接测量的圆速度函数,代表在60 < v_circ < 320 km/s的所有形态类型的星系在给定的旋转速度。对于低质量星系群(60 < v_circ < 170 km/s),我们使用HIPASS速度函数。对于大质量星系群(170 < v_circ < 320 km/s),我们使用来自Calar Alto Legacy Integral Field Area Survey(CALIFA)的恒星圆速度。在早期的工作中,我们获得了226个星系在80%光半径处的圆速度测量值,并证明了CALIFA样品可以产生体积校正的星系分布函数。CALIFA的速度函数包括均匀的速度测量的晚型和早型旋转支持的星系,并具有关键的优势,不错过气体贫乏的大质量椭圆,HI调查是盲目的。我们表明,这两个速度函数可以以无缝的方式相结合,因为它们的有效性范围重叠。所得到的观察到的速度函数相比,来自宇宙学模拟的z = 0星系人口的速度函数。我们发现,暗物质-只有模拟显示出强烈的不匹配所观察到的VF。流体动力学模拟效果更好,但仍然不能完全再现观测结果。

英文摘要:

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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