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| Main Authors: | , , , , , , , |
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| Format: | Preprint |
| Published: |
2022
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2206.10405 |
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| _version_ | 1866913246970118144 |
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| author | Tenachi, Wassim Oria, Pierre-Antoine Ibata, Rodrigo Famaey, Benoit Yuan, Zhen Arentsen, Anke Martin, Nicolas Viswanathan, Akshara |
| author_facet | Tenachi, Wassim Oria, Pierre-Antoine Ibata, Rodrigo Famaey, Benoit Yuan, Zhen Arentsen, Anke Martin, Nicolas Viswanathan, Akshara |
| contents | We report on the discovery in the Gaia DR3 astrometric and spectroscopic catalog of a new polar stream that is found as an over-density in action space. This structure is unique as it has an extremely large apocenter distance, reaching beyond 100 kpc, and yet is detected as a coherent moving structure in the Solar neighborhood with a width of $\sim 4$ kpc. A sub-sample of these stars that was fortuitously observed by LAMOST has a mean spectroscopic metallicity of $\langle {\rm [Fe/H]}\rangle = -1.60^{+0.15}_{-0.16}$ dex and possesses a resolved metallicity dispersion of $σ({\rm [Fe/H]}) = 0.32^{+0.17}_{-0.06}$ dex. The physical width of the stream, the metallicity dispersion and the vertical action spread indicate that the progenitor was a dwarf galaxy. The existence of such a coherent and highly radial structure at their pericenters in the vicinity of the Sun suggests that many other dwarf galaxy fragments may be lurking in the outer halo. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2206_10405 |
| institution | arXiv |
| publishDate | 2022 |
| record_format | arxiv |
| spellingShingle | Typhon: a polar stream from the outer halo raining through the Solar neighborhood Tenachi, Wassim Oria, Pierre-Antoine Ibata, Rodrigo Famaey, Benoit Yuan, Zhen Arentsen, Anke Martin, Nicolas Viswanathan, Akshara Astrophysics of Galaxies We report on the discovery in the Gaia DR3 astrometric and spectroscopic catalog of a new polar stream that is found as an over-density in action space. This structure is unique as it has an extremely large apocenter distance, reaching beyond 100 kpc, and yet is detected as a coherent moving structure in the Solar neighborhood with a width of $\sim 4$ kpc. A sub-sample of these stars that was fortuitously observed by LAMOST has a mean spectroscopic metallicity of $\langle {\rm [Fe/H]}\rangle = -1.60^{+0.15}_{-0.16}$ dex and possesses a resolved metallicity dispersion of $σ({\rm [Fe/H]}) = 0.32^{+0.17}_{-0.06}$ dex. The physical width of the stream, the metallicity dispersion and the vertical action spread indicate that the progenitor was a dwarf galaxy. The existence of such a coherent and highly radial structure at their pericenters in the vicinity of the Sun suggests that many other dwarf galaxy fragments may be lurking in the outer halo. |
| title | Typhon: a polar stream from the outer halo raining through the Solar neighborhood |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2206.10405 |