THE SIZE–VIRIAL RADIUS RELATION OF GALAXIES
THE SIZE–VIRIAL RADIUS RELATION OF GALAXIES
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DOI：
10.1088/2041-8205/764/2/l31
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发表时间：
2012-12
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影响因子：
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通讯作者：
A. Kravtsov
中科院分区：
文献类型：
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作者：
A. Kravtsov
我使用的丰度匹配的ANEQUALITY，这已被证明是成功的复制星系聚类和其他统计数据，推导出的维里半径，R200，不同形态类型的星系和广泛的恒星质量的估计。我表明，超过8个数量级的恒星质量星系的所有形态类型遵循近似线性关系的半质量半径的恒星分布，r1/2，维里半径，r1/2 <$0.015 R200，与散射<$0.2德克斯。这样的尺度与模型的预期非常一致，模型假设星系的大小由晕的角动量r1/2 <$λR200控制，其中λ是星系母晕的自旋。该关系的离散度与λ分布的预期离散度相当。此外，我表明，当不同形态类型的星系的恒星和气体的表面密度分布的半径rn = 0.015 R200重新标度，重新标度的轮廓符合近似普适指数（晚期类型）和德Vaucouleurs（早期类型）的形式，只有约30%-50%的分散在R <$1 -3rn。值得注意的是，晚型星系和早型星系在R 1 rn处有相似的平均恒星表面密度分布。因此，它们的恒星分布之间的主要区别是在R < rn处。研究结果表明，星系的大小和重子的径向分布主要受其母晕性质的影响，晚型盘和早型球状体的大小都受母晕角动量的控制。
I use the abundance matching ansatz, which has proven to be successful in reproducing galaxy clustering and other statistics, to derive estimates of the virial radius, R200, for galaxies of different morphological types and a wide range of stellar masses. I show that over eight orders of magnitude in stellar mass galaxies of all morphological types follow an approximately linear relation between half-mass radius of their stellar distribution, r1/2, and virial radius, r1/2 ≈ 0.015 R200, with scatter of ≈0.2 dex. Such scaling is in remarkable agreement with the expectation of models that assume that galaxy sizes are controlled by halo angular momentum, r1/2∝λR200, where λ is the spin of galaxy parent halo. The scatter about the relation is comparable with the scatter expected from the distribution of λ. Moreover, I show that when the stellar and gas surface density profiles of galaxies of different morphological types are rescaled by the radius rn = 0.015 R200, the rescaled profiles follow approximately universal exponential (for late types) and de Vaucouleurs (for early types) form with scatter of only ≈30%–50% at R ≈ 1–3rn. Remarkably, both late- and early-type galaxies have similar mean stellar surface density profiles at R ≳ 1rn. The main difference between their stellar distributions is thus at R < rn. The results of this study imply that galaxy sizes and radial distribution of baryons are shaped primarily by properties of their parent halos and that the sizes of both late-type disks and early-type spheroids are controlled by halo angular momentum.