论文标题
皇后。 viii。原始的新确定，他具有极为金属贫困的星系的丰富性：麻轻顿不对称的建议及其对哈勃张力的影响
EMPRESS. VIII. A New Determination of Primordial He Abundance with Extremely Metal-Poor Galaxies: A Suggestion of the Lepton Asymmetry and Implications for the Hubble Tension
论文作者
论文摘要
他丰富的原始$ y_ \ mathrm {p} $是对宇宙学的强大探测。目前，$ y_ \ mathrm {p} $最好是通过对金属贫困星系的观察来确定的，而只有少数已知的本地极为金属罚款（$ <0.1 z_ \ odot $）星系（EMPGS）可靠地使用HEI $ 10830近传输（nir）（NIR），具有可靠的He/H测量值。在这里，我们提出了10个EMPG的深层Subaru NIR光谱。结合了现有的光学数据，Markov链蒙特卡洛算法可靠地得出了10个EMPG中5个的He/H值。添加现有的3个EMPG和51个中等金属罚款（$ 0.1-0.4 Z_ \ ODOT $）星系，具有可靠的He/H估计值，我们获得了$ Y_ \ Mathrm {P} = 0.2370^{+0.0034} $ \ mathrm {（He/h）} - \ Mathrm {（o/h）} $ plane，在那里我们将EMPG的数量从3个锚定为星系中最金属贫困气体的He/H。尽管我们的$ y_ \ mathrm {p} $测量和以前的测量是一致的，但由于我们的EMPG，我们的结果略小（$ \ sim1σ$）。 With our $Y_\mathrm{P}$ and the existing primordial deuterium $D_\mathrm{P}$ measurement, we constrain the effective number of neutrino species $N_\mathrm{eff}$ and the baryon-to-photon ratio $η$ showing $\gtrsim 1-2σ$ tensions with the Standard Model and Planck Collaboration et al. （2020）。在紧张局势的激励下，我们允许电子neutrino $ξ_e$的退化参数变化，以及$ n_ \ mathrm {eff} $和$η$。我们获得$ξ_e= 0.05^{+0.03} _ { - 0.02} $，$ n_ \ mathrm {eff} = 3.11^{+0.34} _ { - 0.31} $ $ y_ \ Mathrm {p} $和$ d_ \ mathrm {p} $测量值，以$η$的先验为单位，取自Planck Collaboration等。 （2020）。我们的约束表明了Lepton的不对称性，并允许在$1σ$级别内高价值$ N_ \ Mathrm {eff} $，从而可以减轻Hubble张力。
The primordial He abundance $Y_\mathrm{P}$ is a powerful probe of cosmology. Currently, $Y_\mathrm{P}$ is best determined by observations of metal-poor galaxies, while there are only a few known local extremely metal-poor ($<0.1 Z_\odot$) galaxies (EMPGs) having reliable He/H measurements with HeI$λ$10830 near-infrared (NIR) emission. Here we present deep Subaru NIR spectroscopy for 10 EMPGs. Combining the existing optical data, He/H values of 5 out of the 10 EMPGs are reliably derived by the Markov chain Monte Carlo algorithm. Adding the existing 3 EMPGs and 51 moderately metal-poor ($0.1-0.4 Z_\odot$) galaxies with reliable He/H estimates, we obtain $Y_\mathrm{P}=0.2370^{+0.0034}_{-0.0033}$ by linear regression in the $\mathrm{(He/H)}-\mathrm{(O/H)}$ plane, where we increase the number of EMPGs from 3 to 8 anchoring He/H of the most metal-poor gas in galaxies. Although our $Y_\mathrm{P}$ measurement and previous measurements are consistent, our result is slightly ($\sim 1σ$) smaller due to our EMPGs. With our $Y_\mathrm{P}$ and the existing primordial deuterium $D_\mathrm{P}$ measurement, we constrain the effective number of neutrino species $N_\mathrm{eff}$ and the baryon-to-photon ratio $η$ showing $\gtrsim 1-2σ$ tensions with the Standard Model and Planck Collaboration et al. (2020). Motivated by the tensions, we allow the degeneracy parameter of electron-neutrino $ξ_e$ to vary as well as $N_\mathrm{eff}$ and $η$. We obtain $ξ_e = 0.05^{+0.03}_{-0.02}$, $N_\mathrm{eff}=3.11^{+0.34}_{-0.31}$, and $η\times10^{10}=6.08^{+0.06}_{-0.06}$ from the $Y_\mathrm{P}$ and $D_\mathrm{P}$ measurements with a prior of $η$ taken from Planck Collaboration et al. (2020). Our constraints suggest a lepton asymmetry and allow for a high value of $N_\mathrm{eff}$ within the $1σ$ level, which could mitigate the Hubble tension.
