ON THE MASS OF THE LOCAL GROUP
ON THE MASS OF THE LOCAL GROUP
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DOI：
10.1088/0004-637x/793/2/91
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发表时间：
2013-12
期刊：
影响因子：
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通讯作者：
R. González;A. Kravtsov;N. Gnedin
中科院分区：
文献类型：
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作者：
R. González;A. Kravtsov;N. Gnedin
我们使用最近自行测量的切向速度的M31，沿着其径向速度和距离，推导出银河系和M31的晕质量的总和的可能性。这是使用在ΛCDM宇宙学的Bolshoi宇宙学模拟中的晕对样本来完成的，这些样本被选择来匹配本地群的属性和环境。由此产生的似然性给出了MMW，200 c + MM31，200 c的质量之和的估计值=（90%置信区间）。这个估计与银河系和M31的个别质量估计一致，并且与使用时间参数估计的质量一致，尽管有点偏低。我们表明，虽然时间参数是无偏的平均所有对，对约束有径向和切向速度类似的本地组的参数高估了质量的总和的一个因素为1.6。使用类似的技术，我们估计总暗物质的质量封闭在1百万秒差距的本地集团的重心是（90%的置信区间）。
We use recent proper motion measurements of the tangential velocity of M31, along with its radial velocity and distance, to derive the likelihood of the sum of halo masses of the Milky Way and M31. This is done using a sample of halo pairs in the Bolshoi cosmological simulation of ΛCDM cosmology selected to match the properties and the environment of the Local Group. The resulting likelihood gives an estimate of the sum of the masses of MMW, 200c + MM31, 200c = (90% confidence interval). This estimate is consistent with individual mass estimates for the Milky Way and M31 and is consistent, albeit somewhat on the low side, with the mass estimated using the timing argument. We show that although the timing argument is unbiased on average for all pairs, for pairs constrained to have radial and tangential velocities similar to that of the Local Group the argument overestimates the sum of masses by a factor of 1.6. Using similar technique, we estimate the total dark matter mass enclosed within 1 Mpc from the Local Group barycenter to be (90% confidence interval).