The universal acceleration scale from stellar feedback
The universal acceleration scale from stellar feedback
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DOI：
10.1093/mnrasl/slaa103
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发表时间：
2020-06
影响因子：
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通讯作者：
Michael Y. Grudić;M. Boylan-Kolchin;C. Faucher-Giguère;P. Hopkins
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文献类型：
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作者：
Michael Y. Grudić;M. Boylan-Kolchin;C. Faucher-Giguère;P. Hopkins
几十年来，人们已经证实，在特征加速度标度$g\dagger}\sim 10^-8}，\rm{cm\，S^-2}}$之下，仅给出重子的情况下，自转曲线偏离牛顿引力预期。近年来，理论和观测研究表明，稠密气体的成星效率与面密度成正比，成星效率与星体密度成正比，星体成星效率∼Σ/Σ与Sigma_rm Crit}\sim\langelDot{p}/m_\ast}\Rangel/(\pi，G)\SIM1000\，\Rm{M_(-2)}}$(式中是年轻恒星群中单位质量恒星反馈输出的动量通量)有关。我们认为，更一般地，超临界质量应随局部引力加速度而变化，即：超临界质量应随局部引力加速度而变化，即：超临界质量g_rm tot}/g_rm crit}\EQUV(G\，M_{\rm tot}/R^{2})/\langle\点{p}/m_{\ast}\rangl$，其中mtot为总引力质量，$g_{\rm crit}=\langel点{p}/m_{\ast}\rangg=\pi，G\，Sigma_{\rm Crit}\约10^{-8}\，\rm{cm\，S^{-2}}\约\mathit{g}_{\dagger}$。因此，观测到的g†可能对应于恒星反馈不能阻止有效恒星形成的特征加速尺度，而重子最终将占据主导地位。我们进一步展示了这可能如何引起观测到的加速度标度$g_{\rm obs}\sim(g_{\rm重子}\，g_{\dagger})^{1/2}$(其中gbaryon是仅由重子引起的加速度)和平坦的旋转曲线。导出的特征加速度g†可以用基本常数(引力常数、质子质量和汤姆逊截面)来表示：$g\dagger}\sim 0.1，G\，m{mathrm{p}}/\sigma{rm T}$。
It has been established for decades that rotation curves deviate from the Newtonian gravity expectation given baryons alone below a characteristic acceleration scale $g_{\dagger }\sim 10^{-8}\, \rm {cm\, s^{-2}}$, a scale promoted to a new fundamental constant in MOND. In recent years, theoretical and observational studies have shown that the star formation efficiency (SFE) of dense gas scales with surface density, SFE ∼ Σ/Σcrit with $\Sigma _{\rm crit} \sim \langle \dot{p}/m_{\ast }\rangle /(\pi \, G)\sim 1000\, \rm {M_{\odot }\, pc^{-2}}$ (where $\langle \dot{p}/m_{\ast }\rangle$ is the momentum flux output by stellar feedback per unit stellar mass in a young stellar population). We argue that the SFE, more generally, should scale with the local gravitational acceleration, i.e. that SFE ${\sim}g_{\rm tot}/g_{\rm crit}\equiv (G\, M_{\rm tot}/R^{2}) / \langle \dot{p}/m_{\ast }\rangle$, where Mtot is the total gravitating mass and $g_{\rm crit}=\langle \dot{p}/m_{\ast }\rangle = \pi \, G\, \Sigma _{\rm crit} \approx 10^{-8}\, \rm {cm\, s^{-2}} \approx \mathit{ g}_{\dagger }$. Hence, the observed g† may correspond to the characteristic acceleration scale above which stellar feedback cannot prevent efficient star formation, and baryons will eventually come to dominate. We further show how this may give rise to the observed acceleration scaling $g_{\rm obs}\sim (g_{\rm baryon}\, g_{\dagger })^{1/2}$ (where gbaryon is the acceleration due to baryons alone) and flat rotation curves. The derived characteristic acceleration g† can be expressed in terms of fundamental constants (gravitational constant, proton mass, and Thomson cross-section): $g_{\dagger }\sim 0.1\, G\, m_{\mathrm{ p}}/\sigma _{\rm T}$.