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arXiv 0712.0860astro-ph
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具有高分辨光速场的低表面亮度半导体质量模型

Mass Models for Low Surface Brightness Galaxies with High Resolution Optical Velocity Fields

Rachel Kuzio de Naray, Stacy S. McGaugh, W. J. G. de Blok

摘要:

我们提出了高分辨率的光学速度场从DensePak积分场光谱,以及派生的旋转曲线,低表面亮度星系的样本。在没有重子的限制下,我们拟合了NFW和伪等温晕模型的数据,发现旋转曲线的形状和晕中心密度更好地描述了等温晕。对于这些星系与测光,我们提出了晕适合恒星的质量与光比的三个假设。我们发现,在最大盘和NFW晕相互排斥的情况下,重子的速度贡献是足够显著的。我们发现在星系的中心有大量的尖点质量过剩,在尖点CDM晕中预期的质量至少是数据所允许的两倍。我们还发现,为了使数据与LCDM相一致,需要~20 km/s的非圆运动和/或功率谱在我们探测的尺度上具有较低的振幅。

英文摘要:

We present high-resolution optical velocity fields from DensePak integral field spectroscopy, along with derived rotation curves, for a sample of low surface brightness galaxies. In the limit of no baryons, we fit the NFW and pseudoisothermal halo models to the data and find the rotation curve shapes and halo central densities to be better described by the isothermal halo. For those galaxies with photometry, we present halo fits for three assumptions of the stellar mass-to-light ratio. We find that the velocity contribution from the baryons is significant enough in the maximum disk case that maximum disk and the NFW halo are mutually exclusive. We find a substantial cusp mass excess at the centers of the galaxies, with at least two times more mass expected in the cuspy CDM halo than is allowed by the data. We also find that to reconcile the data with LCDM, ~20 km/s noncircular motions are needed and/or the power spectrum has a lower amplitude on the scales we probe.

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