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The missing massive satellites of the Milky Way

文献类型：期刊论文

作者Wang, Jie1; Frenk, Carlos S.1; Navarro, Julio F.2; Gao, Liang3; Sawala, Till1
刊名MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
出版日期2012-08-01
卷号424期号:4页码:2715-2721
关键词Galaxy: abundances Galaxy: halo dark matter
英文摘要Recent studies suggest that only three of the 12 brightest satellites of the Milky Way (MW) inhabit dark matter haloes with maximum circular velocity, V-max, exceeding similar to 30 kms(-1). This is in apparent contradiction with the Lambda cold dark matter (CDM) simulations of the Aquarius Project, which suggest that MW-sized haloes should have at least eight subhaloes with V-max > 30 kms(-1). The absence of luminous satellites in such massive subhaloes is thus puzzling and may present a challenge to the Lambda CDM paradigm. We note, however, that the number of massive subhaloes depends sensitively on the (poorly known) virial mass of the MW, and that their scarcity makes estimates of their abundance from a small simulation set like Aquarius uncertain. We use the Millennium Simulation series and the invariance of the scaled subhalo velocity function (i.e. the number of subhaloes as a function of nu, the ratio of the subhalo V-max to the host halo virial velocity, V-200) to secure improved estimates of the abundance of rare massive subsystems. In the range 0.1 nu) is approximately Poisson distributed about an average given by < N-sub > = 10.2 (nu/0.15)(-3.11). This is slightly lower than that in Aquarius haloes, but consistent with recent results from the Phoenix Project. The probability that a Lambda CDM halo has three or fewer subhaloes with V-max above some threshold value, V-th, is then straightforward to compute. It decreases steeply both with decreasing V-th and with increasing halo mass. For V-th = 30 kms(-1), similar to 40 per cent of M-halo = 10(12) M-circle dot haloes pass the test; fewer than similar to 5 per cent do so for M-halo >= 2 x 10(12) M-circle dot and the probability effectively vanishes for M-halo >= 3 x 10(12) M-circle dot. Rather than a failure of Lambda CDM, the absence of massive subhaloes might simply indicate that the MW is less massive than is commonly thought.
收录类别SCI
语种英语
WOS记录号WOS:000307385100024
源URL[http://ir.bao.ac.cn/handle/114a11/6092]  
专题国家天文台_星系宇宙学研究部
作者单位1.Univ Durham, Dept Phys, Inst Computat Cosmol, Durham DH1 3LE, England
2.Univ Victoria, Dept Phys & Astron, Victoria, BC V8W 3P6, Canada
3.Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China
推荐引用方式
GB/T 7714		 Wang, Jie,Frenk, Carlos S.,Navarro, Julio F.,et al. The missing massive satellites of the Milky Way[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2012,424(4):2715-2721.
APA Wang, Jie,Frenk, Carlos S.,Navarro, Julio F.,Gao, Liang,&Sawala, Till.(2012).The missing massive satellites of the Milky Way.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,424(4),2715-2721.
MLA Wang, Jie,et al."The missing massive satellites of the Milky Way".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 424.4(2012):2715-2721.

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