Measuring the Hubble Constant through the Galaxy Pairwise Peculiar Velocity
The Hubble constant H _0 , the current expansion rate of the Universe, is one of the most important parameters in cosmology. The cosmic expansion regulates the mutually approaching motion of a pair of celestial objects due to their gravity. Therefore, the mean pairwise peculiar velocity of celestial...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2024-01-01
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| Series: | The Astrophysical Journal Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/2041-8213/ad9aa7 |
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| Summary: | The Hubble constant H _0 , the current expansion rate of the Universe, is one of the most important parameters in cosmology. The cosmic expansion regulates the mutually approaching motion of a pair of celestial objects due to their gravity. Therefore, the mean pairwise peculiar velocity of celestial objects, which quantifies their relative motion, is sensitive to both H _0 and the dimensionless total matter density Ω _m . Based on this, using the Cosmicflows-4 data, we measured H _0 for the first time via the galaxy pairwise velocity in the nonlinear and quasi-linear range. Our results yield H _0 = 75.5 ± 1.4 km s ^−1 Mpc ^−1 and ${{\rm{\Omega }}}_{m}=0.31{1}_{-0.028}^{+0.029}$ . The uncertainties of H _0 and Ω _m can be improved to around 0.6% and 2%, respectively, if the statistical errors become negligible in the future. |
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| ISSN: | 2041-8205 |