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A galaxy lacking dark matter

机译：缺乏暗物质的星系

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摘要

Studies of galaxy surveys in the context of the cold dark matter paradigm have shown that the mass of the dark matter halo and the total stellar mass are coupled through a function that varies smoothly with mass. Their average ratio M-halo/M-stars has a minimum of about 30 for galaxies with stellar masses near that of the Milky Way (approximately 5 x 10(10) solar masses) and increases both towards lower masses and towards higher masses(1,2). The scatter in this relation is not well known; it is generally thought to be less than a factor of two for massive galaxies but much larger for dwarf galaxies(3,4). Here we report the radial velocities of ten luminous globular-cluster-like objects in the ultra-diffuse galaxy(5) NGC1052-DF2, which has a stellar mass of approximately 2 x 10(8) solar masses. We infer that its velocity dispersion is less than 10.5 kilometres per second with 90 per cent confidence, and we determine from this that its total mass within a radius of 7.6 kiloparsecs is less than 3.4 x 10(8) solar masses. This implies that the ratio M-halo/M-stars is of order unity (and consistent with zero), a factor of at least 400 lower than expected(2). NGC1052-DF2 demonstrates that dark matter is not always coupled with baryonic matter on galactic scales.
机译：在冷暗物质范例的背景下进行的银河调查研究表明，暗物质晕的质量和总星体质量是通过随质量平滑变化的函数耦合的。对于恒星质量接近银河系的星系（大约5 x 10（10）太阳质量），它们的M-halo / M-stars平均比率至少约为30，并且朝着较低质量和朝着较高质量增加（1 ，2）。这种关系的散布是未知的。对于大质量星系，通常认为它小于二分之一，而对于矮星系，它要大得多（3,4）。在这里，我们报告了超散射星系（5）NGC1052-DF2中的十个球形球状团簇物体的径向速度，其中恒星质量约为2 x 10（8）太阳质量。我们推断出它的速度色散小于每秒10.5公里，置信度为90％，由此我们可以确定，它在7.6千帕秒半径内的总质量小于3.4 x 10（8）太阳质量。这意味着M-halo / M-stars之比为1阶（且与零一致），比预期值低至少400倍（2）。 NGC1052-DF2证明在银河系尺度上暗物质并不总是与重子物质结合。

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  • 来源
    《Nature》 |2018年第7698期|629-632|共4页
  • 作者

    van Dokkum Pieter; Danieli Shany; Cohen Yotam; Merritt Allison; Romanowsky Aaron J.; Abraham Roberto; Brodie Jean; Conroy Charlie; Lokhorst Deborah; Mowla Lamiya; OSullivan Ewan; Zhang Jielai;

  • 作者单位

    Yale Univ, Dept Astron, New Haven, CT 06511 USA;

    Yale Univ, Dept Astron, New Haven, CT 06511 USA;

    Yale Univ, Dept Astron, New Haven, CT 06511 USA;

    Yale Univ, Dept Astron, New Haven, CT 06511 USA;

    San Jose State Univ, Dept Phys & Astron, San Jose, CA 95192 USA;

    Univ Toronto, Dept Astron & Astrophys, 50 St George St, Toronto, ON M5S 3H4, Canada;

    Univ Calif Observ, 1156 High St, Santa Cruz, CA 95064 USA;

    Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA;

    Univ Toronto, Dept Astron & Astrophys, 50 St George St, Toronto, ON M5S 3H4, Canada;

    Yale Univ, Dept Astron, New Haven, CT 06511 USA;

    Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA;

    Univ Toronto, Dept Astron & Astrophys, 50 St George St, Toronto, ON M5S 3H4, Canada;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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