Understanding the shape and diversity of dwarf galaxy rotation curves in ΛCDM
Understanding the shape and diversity of dwarf galaxy rotation curves in ΛCDM
复制标题
了解ΛCDM中矮星系旋转曲线的形状和多样性
DOI：
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
F. Fraternali
中科院分区：
文献类型：
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作者：
J. Read;G. Iorio;G. Iorio;O. Agertz;F. Fraternali
矮星系自转曲线的形状和多样性与LCDM中的暗物质晕明显不一致。我们从矮星系模拟中生成模拟旋转曲线数据，以表明这是由于恒星反馈驱动的爆发性星星形成。有三个主要影响。首先，恒星反馈将暗物质尖端转变为核心。忽略这样的变换导致旋转曲线形状的差拟合和晕圈浓度参数c的大的系统偏差。其次，如果接近最近的恒星暴，大的HI气泡会使旋转曲线失去平衡。这使得气体的旋转速度的潜在的穷人探针，导致系统误差的晕维里质量M200的半德克斯。第三，当星系在近正面（i<40度）观察时，正确校正它们的倾角i是具有挑战性的。这导致旋转曲线非常浅，M200的系统性低估超过dex。这三个问题都可以很容易地避免。使用一个新的coreNFW配置文件，占尖核转换，我们表明，我们能够成功地恢复旋转曲线的形状，暗物质晕质量M200，和浓度参数c在我们引用的不确定性，只要星系接近平衡。我们适合我们的核心NFW模型四矮不规则选择跨越一系列的旋转曲线形状。我们得到了NGC 6822和WLM的一个很好的拟合。然而，IC 1613和DDO 101给出了较差的拟合。对于IC 1613，这归因于不平衡和其不确定的倾斜;对于DDO 101，问题在于其不确定的距离。假设i_IC1613 ~ 15度且D_DDO101 ~ 12 Mpc，我们能够很好地拟合这两个星系。我们的结论是，一旦我们避免不平衡的星系，或那些测量不好的倾斜和/或距离，LCDM提供了一个显着的匹配矮星系旋转曲线。
The shape and wide diversity of dwarf galaxy rotation curves is at apparent odds with dark matter halos in LCDM. We generate mock rotation curve data from dwarf galaxy simulations to show that this owes to bursty star formation driven by stellar feedback. There are three main effects. Firstly, stellar feedback transforms dark matter cusps into cores. Ignoring such transformations leads to a poor fit of the rotation curve shape and a large systematic bias on the halo concentration parameter c. Secondly, if close to a recent starburst, large HI bubbles push the rotation curve out of equilibrium. This makes the gas rotational velocity a poor probe of the underlying potential, leading to a systematic error on the halo virial mass M200 of up to half a dex. Thirdly, when galaxies are viewed near face-on (i<40deg), it is challenging to properly correct for their inclination i. This leads to a very shallow rotation curve, with a systematic underestimate of M200 of over a dex. All three problems can be easily avoided, however. Using a new coreNFW profile that accounts for cusp-core transformations, we show that we are able to successfully recover the rotation curve shape; dark matter halo mass M200; and concentration parameter c within our quoted uncertainties, provided that the galaxy is close to equilibrium. We fit our coreNFW model to four dwarf irregulars chosen to span a range of rotation curve shapes. We obtain an excellent fit for NGC 6822 and WLM. However, IC 1613 and DDO 101 give a poor fit. For IC 1613, this owes to disequilibria and its uncertain inclination; for DDO 101, the problem is its uncertain distance. Assuming i_IC1613 ~ 15deg and D_DDO101 ~ 12Mpc, we are able to fit both galaxies very well. We conclude that, once we avoid disequilibrium galaxies, or those with poorly measured inclination and/or distance, LCDM gives a remarkable match to dwarf galaxy rotation curves.
DOI：
10.1088/2041-8205/730/2/l13
发表时间：
2011-02
期刊：
The Astrophysical Journal Letters
影响因子：
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作者：
F. Bigiel;A. Leroy;F. Walter;E. Brinks;W. D. Blok;C. Kramer;H. Rix;A. Schruba;K. Schuster;A. Usero;H. Wiesemeyer
通讯作者：
F. Bigiel;A. Leroy;F. Walter;E. Brinks;W. D. Blok;C. Kramer;H. Rix;A. Schruba;K. Schuster;A. Usero;H. Wiesemeyer