3D outer bulge structure from near infrared star counts
3D outer bulge structure from near infrared star counts
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DOI：
10.1051/0004-6361:20041218
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发表时间：
2004-07
影响因子：
6.5
通讯作者：
S. Picaud;A. Besancon;Astronomisches Rechen-Institut Heidelberg
中科院分区：
文献类型：
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作者：
S. Picaud;A. Besancon;Astronomisches Rechen-Institut Heidelberg
我们试图研究存在于银河系中心区域的不同恒星群的特征。采用蒙特卡罗方法，对DENIS近100个窗口近红外大尺度观测数据（Ks, J - Ks）在- 8◦< l < 12◦和|b| < 4◦处的（Ks, J - Ks）星计数数据同时拟合了11个薄圆盘和三轴外凸密度参数。采用种群合成方案测试了各种凸起密度曲线和光度函数。通过最大似然检验选择的最佳模型给出了以下描述：外凸起是方形的，延长的，并且相对于太阳中心方向定向10.6◦±3◦。似乎主要的膨胀人口年龄不超过10岁，但这一初步结果需要进一步的工作来证实。在薄圆盘的中间发现了一个重要的中心孔。我们讨论这些结果关于以前的发现和情节隆起的形成。
We attempt to study the characteristics of the different stellar populations present in the Galactic central region. A Monte Carlo method is used to simultaneously fit 11 thin disc and triaxial outer bulge density parameters on (Ks, J − Ks )s tar count data in almost 100 windows from the DENIS near infrared large scale survey at −8 ◦ < l < 12 ◦ and |b| < 4 ◦ . Various bulge density profiles and luminosity functions were tested using a population synthesis scheme. The best models, selected by a maximum likelihood test, give the following description: the outer bulge is boxy, prolate, and oriented 10.6 ◦ ± 3 ◦ with respect to the Sun-center direction. It seems that the main bulge population is not older than 10 Gyr, but this preliminary result needs further work to be confirmed. A significant central hole is found in the middle of the thin disc. We discuss these results in regard to previous findings and the scenario of bulge formation.