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

Abstract

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 ($<0.1Z_{\odot }$) galaxies (EMPGs) having reliable He/H measurements with HeI$\lambda$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 ($0.1-0.4Z_{\odot }$) galaxies with reliable He/H estimates, we obtain $Y_{\mathrm{P}}=0.2370_{-0.0033}^{+0.0034}$ by linear regression in the $(He/H)-(O/H)$ 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 ($\sim 1\sigma$) 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 $\eta$ showing $\gtrsim 1-2\sigma$ tensions with the Standard Model and Planck Collaboration et al. (2020). Motivated by the tensions, we allow the degeneracy parameter of electron-neutrino ${\xi }_e$ to vary as well as $N_{\mathrm{eff}}$ and $\eta$. We obtain ${\xi }_e=0.05_{-0.02}^{+0.03}$, $N_{\mathrm{eff}}=3.11_{-0.31}^{+0.34}$, and $\eta \times 10^{10}=6.08_{-0.06}^{+0.06}$ from the $Y_{\mathrm{P}}$ and $D_{\mathrm{P}}$ measurements with a prior of $\eta$ 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 $1\sigma$ level, which could mitigate the Hubble tension.

22 pages, 9 figures, accepted for publication in ApJ

References in corpus (26)

• A Comprehensive Measurement of the Local Value of the Hubble Constant with 1 km/s/Mpc Uncertainty from the Hubble Space Telescope and the SH0ES Team
• Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination of the Hubble Constant and Stronger Evidence for Physics Beyond LambdaCDM
• The trouble with $H_0$
• Primordial Nucleosynthesis in the Precision Cosmology Era
• Primordial Nucleosynthesis: from precision cosmology to fundamental physics
• The effects of He I 10830 on helium abundance determinations
• On the Hubble constant tension in the SNe Ia Pantheon sample
• On the evolution of the Hubble constant with the SNe Ia Pantheon Sample and Baryon Acoustic Oscillations: a feasibility study for GRB-cosmology in 2030
• Galileon Gravity in Light of ISW, CMB, BAO and $H_0$ data
• Extremely metal-poor star-forming galaxies. New detections and general morphological and photometric properties
• EMPRESS. V. Metallicity Diagnostics of Galaxies over 12+log(O/H)=~6.9-8.9 Established by a Local Galaxy Census: Preparing for JWST Spectroscopy
• The PHLEK Survey: A New Determination of the Primordial Helium Abundance
• Primordial Deuterium after LUNA: concordances and error budget
• PArthENoPE Revolutions
• Determination of the primordial helium abundance based on NGC 346 an HII region of the Small Magellanic Cloud
• Improved constraints on lepton asymmetry from the cosmic microwave background
• A new determination of the primordial helium abundance using the analyses of HII region spectra from SDSS
• J1234+3901: an extremely metal-deficient compact star-forming dwarf galaxy at redshift 0.133
• A Bayesian direct method implementation to fit emission line spectra: Application to the primordial He abundance determination
• EMPRESS. IV. Extremely Metal-Poor Galaxies (EMPGs) Including Very Low-Mass Primordial Systems with M*=10^4--10^5 M_sun and 2--3% (O/H)_sun: High (Fe/O) Suggestive of Metal Enrichment by Hypernovae/Pair-Instability Supernovae
• Lepton Asymmetric Universe
• Probing the properties of relic neutrinos using the cosmic microwave background, the Hubble Space Telescope and galaxy clusters
• Hubble tension in lepton asymmetric cosmology with an extra radiation
• WMAP 5-year constraints on lepton asymmetry and radiation energy density: Implications for Planck
• EMPRESS. VII. Ionizing Spectrum Shapes of Extremely Metal-Poor Galaxies: Uncovering the Origins of Strong HeII and the Impact on Cosmic Reionization
• EMPRESS. VI. Outflows Investigated in Low-Mass Galaxies with $M_{\ast }=10^4-10^7{M}_{\odot }$: Weak Feedback in Low-Mass Galaxies?

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• Big bang nucleosynthesis and early dark energy in light of the EMPRESS $Y_p$ results and the $H_0$ tension
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