The Structure of the Galactic Halo |
| |
Authors: | Cui-Hua Du Zhen-Yu Wu Jun Ma Xu Zhou |
| |
Institution: | [1]College of Physical Sciences, Graduate School of Chinese Academy of Sciences, Beijing 100049, China [2]National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China |
| |
Abstract: | We used the star counts in 21 BATC fields obtained with the National Astronomical Observatories (NAOC) 60/90 cm Schmidt Telescope to study the structure of the Galactic halo.Adopting a de Vaucouleurs γ/4 law halo,we found that the halo is somewhat flatter (c/a~0.4) towards the Galactic center than in the anticentre and antirotation direction (c/a > 0.4).We also notice that the axial ratios are smaller (flatter) towards the low latitude fields than the high latitude fields,except for a few fields.We provide robust limits on the large-scale flattening of the halo.Our analysis shows that the axial ratio of the halo may vary with distance and the observation direction.At large Galactocentric radii,the halo may not have a smooth density distribution,but rather,it may be largely composed of overlapping streams or substructures,which provides a support for the hybrid formation model. |
| |
Keywords: | Galaxy:structure-Galaxy:halo-Galaxy:fundamental parametersGalaxy:formation |
本文献已被 维普 万方数据 等数据库收录! |
|