THE EVOLUTION OF THE MBH–σ RELATION INFERRED FROM THE AGE DISTRIBUTION OF LOCAL EARLY-TYPE GALAXIES AND ACTIVE GALACTIC NUCLEI EVOLUTION
THE EVOLUTION OF THE MBH–σ RELATION INFERRED FROM THE AGE DISTRIBUTION OF LOCAL EARLY-TYPE GALAXIES AND ACTIVE GALACTIC NUCLEI EVOLUTION
复制标题
从局域早型星系年龄分布和活动星系核演化推论MBH-σ关系的演化
DOI：
10.1088/0004-637x/694/2/867
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
Z. Haiman
中科院分区：
文献类型：
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作者：
F. Shankar;M. Bernardi;Z. Haiman
我们利用球状体的局部速度色散函数（VDF），结合它们的年龄分布，在假设（1）每个球状体附近的大多数恒星都是在一个事件中形成的，（2）速度色散σ在之后几乎保持不变的情况下，预测了较高红移（0 < z <$6）的VDF。我们进一步假设，超大质量黑洞与恒星同时形成，并且在椭球体势阱形成的±1 Gyr内，黑洞质量与宿主速度色散之间的关系保持MBH <$σβ与β <$4的形式，但允许归一化随红移演变为<$（1 + z）α。我们计算的BH质量函数与VDF在每个红移，并比较累计总BH质量密度与推断的综合类星体光度函数（LF;所谓的Socluttan参数）。这种比较对类星体活动的占空比或爱丁顿比不敏感，我们发现两个BH质量密度之间的匹配有利于相对温和的红移演化，α = 0.33，在超过99%的置信水平下排除了α = 1.3的正演化。在基于VDF的BH质量函数和基于类星体LF的BH质量函数中，特征BH质量之间的直接匹配也产生了λ <$0.5 -1的平均爱丁顿比，该比在0 <$z <$3内大致恒定。如果星系从形成的那一刻起由于耗散过程而平均增加了它们的速度色散，那么数据仍然允许MBH-σ关系中的强正演化。如果我们假设宿主星系的平均速度色散演化为σ（z）= σ（0）×（1 + z）−γ，我们发现当α = 1.5时，γ = 0.23的下限。后一种估计代表了星系演化模型的一个有趣的约束条件，可以通过水力模拟进行测试。然而，这种耗散模型也意味着在较高的z处λ减小，与几项独立研究不同。
We utilize the local velocity dispersion function (VDF) of spheroids, together with their inferred age distributions, to predict the VDF at higher redshifts (0 < z ≲ 6), under the assumption that (1) most of the stars in each nearby spheroid formed in a single episode and, (2) the velocity dispersion σ remained nearly constant afterward. We assume further that a supermassive BH forms concurrently with the stars, and within ±1 Gyr of the formation of the potential well of the spheroid, and that the relation between the mass of the BH and host velocity dispersion maintains the form MBH ∝ σβ with β ≈ 4, but with the normalization allowed to evolve with redshift as ∝(1 + z)α. We compute the BH mass function associated with the VDF at each redshift, and compare the accumulated total BH mass density with that inferred from the integrated quasar luminosity function (LF; the so-called Sołtan argument). This comparison is insensitive to the assumed duty cycle or Eddington ratio of quasar activity, and we find that the match between the two BH mass densities favors a relatively mild redshift evolution, with α ∼ 0.33, with a positive evolution as strong as α ≳ 1.3 excluded at more than 99% confidence level. A direct match between the characteristic BH mass in the VDF-based and quasar LF-based BH mass functions also yields a mean Eddington ratio of λ ∼ 0.5–1 that is roughly constant within 0 ≲ z ≲ 3. A strong positive evolution in the MBH–σ relation is still allowed by the data if galaxies increase, on average, their velocity dispersions since the moment of formation due to dissipative processes. If we assume that the mean velocity dispersion of the host galaxies evolves as σ(z) = σ(0) × (1 + z)−γ, we find a lower limit of γ ≳ 0.23 for α ≳ 1.5. The latter estimate represents an interesting constraint for galaxy evolution models and can be tested through hydro simulations. This dissipative model, however, also implies a decreasing λ at higher z, at variance with several independent studies.
DOI：
10.1111/j.1365-2966.2008.13553.x
发表时间：
2008-06
影响因子：
4.8
作者：
K. Coppin;M. Swinbank;R. Neri;P. Cox;D. Alexander;I. Smail;M. Page;J. Stevens;K. Knudsen;R. Ivison;A. Beelen;F. Bertoldi;A. Cosmology;D. University;Iram;D. Physics;Mssl;University College London;CfAR;U. Hertfordshire;AIfA;U. Bonn;Ifa;U. Edinburgh;UK-ATC;Ias;U. Paris-sud;Iap;Universit'e PierreMarie Curie
通讯作者：
K. Coppin;M. Swinbank;R. Neri;P. Cox;D. Alexander;I. Smail;M. Page;J. Stevens;K. Knudsen;R. Ivison;A. Beelen;F. Bertoldi;A. Cosmology;D. University;Iram;D. Physics;Mssl;University College London;CfAR;U. Hertfordshire;AIfA;U. Bonn;Ifa;U. Edinburgh;UK-ATC;Ias;U. Paris-sud;Iap;Universit'e PierreMarie Curie
DOI：
10.1086/587475
发表时间：
2007-09
期刊：
The Astrophysical Journal
影响因子：
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作者：
Yue Shen;J. Greene;M. Strauss;G. Richards;D. Schneider
通讯作者：
Yue Shen;J. Greene;M. Strauss;G. Richards;D. Schneider
国家射电天文台/NASA/德克萨斯大学（美国）
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