• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The Astrophysical journal >Can Supermassive Black Holes Form In Metal-enriched High-redshift Protogalaxies?
【24h】

Can Supermassive Black Holes Form In Metal-enriched High-redshift Protogalaxies?

机译：富含金属的高红移原星系会形成超大质量黑洞吗？

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Primordial gas in protogalactic DM halos with virial temperatures T_(vir) approx > 10~4 K begins to cool and condense via atomic hydrogen. Provided that this gas is irradiated by a strong UV flux and remains free of H_2 and other molecules, it has been proposed that the halo with T_(vir) ～ 10~4 K may avoid fragmentation and lead to the rapid formation of an SMBH as massive as M ≈ 10~5-10~6 M_☉. This "head start" would help explain the presence of SMBHs with inferred masses of several times 10~9 M_☉, powering the bright quasars discovered in the SDSS at redshift z approx > 6. However, high-redshift DM halos with T_(vir) ～ 10~4 K are likely already enriched with at least trace amounts of metals and dust produced by prior star formation in their progenitors. Here we study the thermal and chemical evolution of low-metallicity gas exposed to extremely strong UV radiation fields. Our results, obtained in one-zone models, suggest that gas fragmentation is inevitable above a critical metallicity, whose value is between Z_(cr) ≈ 3 × 10~(-4) Z_☉ (in the absence of dust) and as low as Z_(cr) ≈ 5 × 10~(-6) Z_☉ (with a dust-to-gas mass ratio of about 0.01 Z/Z_☉). We propose that when the metallicity exceeds these critical values, dense clusters of low-mass stars may form at the halo nucleus. Relatively massive stars in such a cluster can then rapidly coalesce into a single more massive object, which may produce an intermediate-mass BH remnant with a mass up to M appqox < 10~2-10~3 M_☉.
机译：原银DM光晕中的原始气体的病毒温度T_（vir）大约> 10〜4 K，开始通过原子氢进行冷却和冷凝。假设这种气体被强紫外线辐射并保持不含H_2和其他分子，则有人提出T_（vir）〜10〜4 K的卤素可以避免碎裂并导致SMBH快速形成。如M≈10〜5-10〜6M_☉。这种“开端”将有助于解释推断质量为10〜9M_☉数倍的SMBH的存在，从而为SDSS中发现的亮类星体提供了红移z大约>6。但是，高红移DM光晕与T_（vir ）〜10〜4 K可能已经在其祖先中富集了至少痕量的由先前恒星形成而产生的金属和尘埃。在这里，我们研究暴露于极强紫外线辐射场下的低金属气体的热化学演化。我们在一个区域模型中获得的结果表明，在金属临界温度以上，气体破碎是不可避免的，其临界值在Z_（cr）≈3×10〜（-4）Z_☉（无尘）之间且低。 Z_（cr）≈5×10〜（-6）Z_☉（粉尘/气体质量比约为0.01 Z /Z_☉）。我们建议当金属度超过这些临界值时，可能在晕核上形成密集的低质量恒星团。然后，在这样一个星团中相对较大的恒星可以迅速合并为一个更大的物体，这可能会产生质量为M appqox <10〜2-10〜3M_☉的中等质量BH残余物。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号