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arXiv 1008.2162astro-ph.COastro-ph.HE
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z = 3以来超大质量黑洞与宿主星系的协同演化

On the co-evolution of supermassive black holes and their host galaxies since z = 3

Asa F. L. Bluck, Christopher J. Conselice, Omar Almaini, Elise S. Laird, Kirpal Nandra, Ruth Gruetzbauch

摘要:

[摘要]为了研究星系恒星和中心黑洞质量之间关系的演化,我们构造了一个体积有限的85 AGN完整样本,其宿主星系恒星质量M_{*} > 10^{10.5} M_{sol},在0.4 < z < 3时比X射线光度L_{X} > 2.35 x 10^{43} erg s^{-1}。我们计算了居住在这些星系中心的超大质量黑洞的爱丁顿极限质量,并观察到平均爱丁顿极限黑洞质量随红移的增加。通过假设爱丁顿比(μ)没有演变,然后假设存在向爱丁顿极限的最大可能演变,我们将M_{*} / M_{BH}比的最大可能演变量化为位于700 < M_{*}/M_{BH} < 10000的范围内,与M_{*} / M_{BH} ~ 1000的局部值相比。我们还发现,活动星系核(L_{X} > 2.35 x 10^{43} erg s^{-1})的比例随着红移从z = 0.7时的1.2 +/-0.2%上升到z = 2.5时的7.4 +/-2.0%。我们用我们的结果来计算的最大时间尺度,我们的样本AGN可以继续在其观察到的速度吸积超过当地的星系-黑洞质量关系。我们利用这些时间尺度计算了自z = 3以来处于活动状态的大质量星系的总比例(L_{X} > 2.35 x 10^{43} erg s^{-1}),发现在这一时期,至少有40%的大质量星系将是赛弗光度AGN或更亮。此外,我们还计算出活动星系核在宇宙中活动所产生的能量密度为1.0(+/- 0.3)x 10^{57}尔格Mpc^{-3} Gyr^{-1},这可能为活动星系核反馈恒星形成提供了重要的能量来源。我们还用这种方法计算了活动星系核的X射线光度密度随红移的演化,发现大质量星系Seyfert光度活动星系核是宇宙中z < 3时X射线辐射的主要来源。

英文摘要:

[Abridged] To investigate the evolution in the relation between galaxy stellar and central black hole mass we construct a volume limited complete sample of 85 AGN with host galaxy stellar masses M_{*} > 10^{10.5} M_{sol}, and specific X-ray luminosities L_{X} > 2.35 x 10^{43} erg s^{-1} at 0.4 < z < 3. We calculate the Eddington limiting masses of the supermassive black holes residing at the centre of these galaxies, and observe an increase in the average Eddington limiting black hole mass with redshift. By assuming that there is no evolution in the Eddington ratio (μ) and then that there is maximum possible evolution to the Eddington limit, we quantify the maximum possible evolution in the M_{*} / M_{BH} ratio as lying in the range 700 < M_{*}/M_{BH} < 10000, compared with the local value of M_{*}/M_{BH} ~ 1000. We furthermore find that the fraction of galaxies which are AGN (with L_{X} > 2.35 x 10^{43} erg s^{-1}) rises with redshift from 1.2 +/- 0.2 % at z = 0.7 to 7.4 +/- 2.0 % at z = 2.5. We use our results to calculate the maximum timescales for which our sample of AGN can continue to accrete at their observed rates before surpassing the local galaxy-black hole mass relation. We use these timescales to calculate the total fraction of massive galaxies which will be active (with L_{X} > 2.35 x 10^{43} erg s^{-1}) since z = 3, finding that at least ~ 40% of all massive galaxies will be Seyfert luminosity AGN or brighter during this epoch. Further, we calculate the energy density due to AGN activity in the Universe as 1.0 (+/- 0.3) x 10^{57} erg Mpc^{-3} Gyr^{-1}, potentially providing a significant source of energy for AGN feedback on star formation. We also use this method to compute the evolution in the X-ray luminosity density of AGN with redshift, finding that massive galaxy Seyfert luminosity AGN are the dominant source of X-ray emission in the Universe at z < 3.

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