Comment on 'a slightly oblate dark matter halo revealed by a retrograde precessing Galactic disk warp' by Huang et al
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| Autores principales: | , , , , , |
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| Formato: | Preprint |
| Publicado: |
2024
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| _version_ | 1866914862676836352 |
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| author | Dehnen, Walter Schönrich, Ralph Drimmel, Ronald Chrobáková, Žofia Poggio, Eloisa Semczuk, Marcin |
| author_facet | Dehnen, Walter Schönrich, Ralph Drimmel, Ronald Chrobáková, Žofia Poggio, Eloisa Semczuk, Marcin |
| contents | Huang et al. (2024) measured the derivative of the phase $ϕ_{\mathrm{w}}$ of the Galactic warp traced by classical Cepheids with respect to their age $τ$ and interpreted it as the warp precession rate $ω\equiv\mathrm{d}ϕ_{\mathrm{w}}/\mathrm{d}t=-\mathrm{d}ϕ_{\mathrm{w}}/\mathrm{d}τ$. This interpretation is unfounded: young stars follow trajectories close to those of their parental gas and trace the instantaneous gas warp, not its shape at their time of birth: $ϕ_{\mathrm{w}}$ should hardly depend on Cepheid age. We show that the measured $\mathrm{d}ϕ_{\mathrm{w}}/\mathrm{d}τ>0$ is consistent with an omitted-variable bias from neglecting the natural twist $\mathrm{d}ϕ_{\mathrm{w}}/\mathrm{d}R$ of the warp and the $R$-$τ$ correlation for Cepheids (originating from the Galactic metallicity gradient and the Cepheid metallicity-age correlation). |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2407_06341 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Comment on 'a slightly oblate dark matter halo revealed by a retrograde precessing Galactic disk warp' by Huang et al Dehnen, Walter Schönrich, Ralph Drimmel, Ronald Chrobáková, Žofia Poggio, Eloisa Semczuk, Marcin Astrophysics of Galaxies Huang et al. (2024) measured the derivative of the phase $ϕ_{\mathrm{w}}$ of the Galactic warp traced by classical Cepheids with respect to their age $τ$ and interpreted it as the warp precession rate $ω\equiv\mathrm{d}ϕ_{\mathrm{w}}/\mathrm{d}t=-\mathrm{d}ϕ_{\mathrm{w}}/\mathrm{d}τ$. This interpretation is unfounded: young stars follow trajectories close to those of their parental gas and trace the instantaneous gas warp, not its shape at their time of birth: $ϕ_{\mathrm{w}}$ should hardly depend on Cepheid age. We show that the measured $\mathrm{d}ϕ_{\mathrm{w}}/\mathrm{d}τ>0$ is consistent with an omitted-variable bias from neglecting the natural twist $\mathrm{d}ϕ_{\mathrm{w}}/\mathrm{d}R$ of the warp and the $R$-$τ$ correlation for Cepheids (originating from the Galactic metallicity gradient and the Cepheid metallicity-age correlation). |
| title | Comment on 'a slightly oblate dark matter halo revealed by a retrograde precessing Galactic disk warp' by Huang et al |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2407.06341 |