التفاصيل البيبلوغرافية
| العنوان: |
The Local Stellar Halo is Not Dominated by a Single Radial Merger Event |
| المؤلفون: |
Donlon II, Thomas, Newberg, Heidi Jo, Kim, Bokyoung, Lepine, Sebastien |
| سنة النشر: |
2021 |
| مصطلحات موضوعية: |
Astrophysics - Astrophysics of Galaxies |
| الوصف: |
We use halo dwarf stars with photometrically determined metallicities that are located within 2 kpc of the Sun to identify local halo substructure. The kinematic properties of these stars do not indicate a single, dominant radial merger event (RME). The retrograde Virgo Radial Merger (VRM) component has [Fe/H] = -1.7. A second, non-rotating RME component we name Nereus is identified with [Fe/H] = -2.1 and has similar energy as the VRM. A possible third RME we name Cronus is identified that is co-rotating with the disk, has lower energy than the VRM, and has [Fe/H] = -1.2. We identify the Nyx Stream in the data. In addition to these substructures, we observe metal-poor halo stars ([Fe/H] ~ -2.0 and $\sigma_v$ ~ 180 km s$^{-1}$) and a disk/Splash component with lower rotational velocity than the disk and lower metallicity than typically associated with the Splash. An additional excess of halo stars with low velocity and metallicity of [Fe/H] = -1.5 could be associated with the shell of a lower energy RME or indicate that lower energy halo stars have higher metallicity. Stars which comprise the "Gaia Sausage" velocity structure are a combination of the components identified in this work. |
| نوع الوثيقة: |
Working Paper |
| DOI: |
10.3847/2041-8213/ac7531 |
| URL الوصول: |
http://arxiv.org/abs/2110.11465 |
| رقم الانضمام: |
edsarx.2110.11465 |
| قاعدة البيانات: |
arXiv |