TESTING MODIFIED NEWTONIAN DYNAMICS WITH ROTATION CURVES OF DWARF AND LOW SURFACE BRIGHTNESS GALAXIES
TESTING MODIFIED NEWTONIAN DYNAMICS WITH ROTATION CURVES OF DWARF AND LOW SURFACE BRIGHTNESS GALAXIES
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DOI：
10.1088/0004-637x/718/1/380
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发表时间：
2010-05
期刊：
影响因子：
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通讯作者：
R. Swaters;R. Sanders;S. McGaugh
中科院分区：
文献类型：
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作者：
R. Swaters;R. Sanders;S. McGaugh
矮星系和低表面亮度（LSB）星系是测试修正牛顿动力学（MOND）的理想对象，因为在大多数这些星系中，加速度低于MOND适用的阈值。我们从文献中选择了27个矮星系和LSB星系的样本。MOND成功地解释了在这里提供的样本中大约四分之三的星系的观测旋转曲线的一般形状。然而，对于剩下的四分之一，MOND不能充分解释观察到的旋转曲线。考虑到我们样本中星系的距离和倾角的不确定性，一小部分糟糕的MOND预测是可以预料的，这不一定是MOND的问题。我们还将MOND加速度常数a0作为自由参数进行拟合，以确定任何系统趋势。我们发现，似乎有中央表面亮度和最佳拟合值a0之间的相关性，在这个意义上说，较低的表面亮度星系往往有较低的a0。然而，这种相关性强烈地依赖于少数星系，其旋转曲线可能是不确定的，因为无论是酒吧或翘曲。如果没有这些星系，就没有太多的证据表明存在这种趋势，但是我们发现的a0 = 0.7 × 10−8 cm s−2的平均值比以前的研究结果要低一些。如果外部引力场是重要的，那么a0的这种较低的拟合值可能会出现。
Dwarf and low surface brightness (LSB) galaxies are ideal objects to test modified Newtonian dynamics (MOND), because in most of these galaxies the accelerations fall below the threshold where MOND supposedly applies. We have selected from the literature a sample of 27 dwarf and LSB galaxies. MOND is successful in explaining the general shape of the observed rotation curves for roughly three quarters of the galaxies in the sample presented here. However, for the remaining quarter, MOND does not adequately explain the observed rotation curves. Considering the uncertainties in distances and inclinations for the galaxies in our sample, a small fraction of poor MOND predictions is expected and is not necessarily a problem for MOND. We have also made fits taking the MOND acceleration constant, a0, as a free parameter in order to identify any systematic trends. We find that there appears to be a correlation between central surface brightness and the best-fit value of a0, in the sense that lower surface brightness galaxies tend to have lower a0. However, this correlation depends strongly on a small number of galaxies whose rotation curves might be uncertain due to either bars or warps. Without these galaxies, there is less evidence of a trend, but the average value we find for a0 ≈ 0.7 × 10−8 cm s−2 is somewhat lower than derived from previous studies. Such lower fitted values of a0 could occur if external gravitational fields are important.