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| Main Authors: | , , , , , , , , , |
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| Format: | Preprint |
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2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2408.06415 |
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| _version_ | 1866913682277007360 |
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| author | Foote, Hayden R. Besla, Gurtina Garavito-Camargo, Nicolás Patel, Ekta Thomas, Guillaume F. Bonaca, Ana Price-Whelan, Adrian M. Peter, Annika H. G. Zaritsky, Dennis Conroy, Charlie |
| author_facet | Foote, Hayden R. Besla, Gurtina Garavito-Camargo, Nicolás Patel, Ekta Thomas, Guillaume F. Bonaca, Ana Price-Whelan, Adrian M. Peter, Annika H. G. Zaritsky, Dennis Conroy, Charlie |
| contents | Stellar streams in the Milky Way are promising detectors of low-mass dark matter (DM) subhalos predicted by $Λ$CDM. Passing subhalos induce perturbations in streams that indicate the presence of the subhalos. Understanding how known DM-dominated satellites impact streams is a crucial step towards using stream perturbations to constrain the properties of dark perturbers. Here, we cross-match a \textit{Gaia} EDR3 and SEGUE member catalog of the Cetus-Palca stream (CPS) with H3 for additional radial velocity measurements and fit the orbit of the CPS using this 6-D data. We demonstrate for the first time that the ultra-faint dwarf Segue 2 had a recent (77$\pm$5 Myr ago) close flyby (within the stream's 2$σ$ width) with the CPS. This interaction enables constraints on Segue 2's mass and density profile at larger radii ($\mathcal{O}(1)$ kpc) than are probed by its stars ($\mathcal{O}(10)$ pc). While Segue 2 is not expected to strongly affect the portion of the stream covered by our 6-D data, we predict that if Segue 2's mass within $\sim 6$ kpc is $5\times 10^9\,M_\odot$, the CPS's velocity dispersion will be $\sim 40$ km s$^{-1}$ larger at $ϕ_1>20^\circ$ than at $ϕ_1<0^\circ$. If no such heating is detected, Segue 2's mass cannot exceed $10^9\,M_\odot$ within $\sim 6$ kpc. The proper motion distribution of the CPS near the impact site is mildly sensitive to the shape of Segue 2's density profile. This study presents a critical test for frameworks designed to constrain properties of dark subhalos from stream perturbations. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2408_06415 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Segue 2 Recently Collided with the Cetus-Palca Stream: New Opportunities to Constrain Dark Matter in an Ultra-Faint Dwarf Foote, Hayden R. Besla, Gurtina Garavito-Camargo, Nicolás Patel, Ekta Thomas, Guillaume F. Bonaca, Ana Price-Whelan, Adrian M. Peter, Annika H. G. Zaritsky, Dennis Conroy, Charlie Astrophysics of Galaxies Stellar streams in the Milky Way are promising detectors of low-mass dark matter (DM) subhalos predicted by $Λ$CDM. Passing subhalos induce perturbations in streams that indicate the presence of the subhalos. Understanding how known DM-dominated satellites impact streams is a crucial step towards using stream perturbations to constrain the properties of dark perturbers. Here, we cross-match a \textit{Gaia} EDR3 and SEGUE member catalog of the Cetus-Palca stream (CPS) with H3 for additional radial velocity measurements and fit the orbit of the CPS using this 6-D data. We demonstrate for the first time that the ultra-faint dwarf Segue 2 had a recent (77$\pm$5 Myr ago) close flyby (within the stream's 2$σ$ width) with the CPS. This interaction enables constraints on Segue 2's mass and density profile at larger radii ($\mathcal{O}(1)$ kpc) than are probed by its stars ($\mathcal{O}(10)$ pc). While Segue 2 is not expected to strongly affect the portion of the stream covered by our 6-D data, we predict that if Segue 2's mass within $\sim 6$ kpc is $5\times 10^9\,M_\odot$, the CPS's velocity dispersion will be $\sim 40$ km s$^{-1}$ larger at $ϕ_1>20^\circ$ than at $ϕ_1<0^\circ$. If no such heating is detected, Segue 2's mass cannot exceed $10^9\,M_\odot$ within $\sim 6$ kpc. The proper motion distribution of the CPS near the impact site is mildly sensitive to the shape of Segue 2's density profile. This study presents a critical test for frameworks designed to constrain properties of dark subhalos from stream perturbations. |
| title | Segue 2 Recently Collided with the Cetus-Palca Stream: New Opportunities to Constrain Dark Matter in an Ultra-Faint Dwarf |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2408.06415 |