Searching for new physics using high precision absorption spectroscopy; continuum placement uncertainties and $Δα/α$ towards the quasar PHL957
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| Main Authors: | , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866910627514023936 |
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| author | Webb, John K. Lee, Chung-Chi Milaković, Dinko Dougan, Darren Dzuba, Vladimir A. Flambaum, Victor V. |
| author_facet | Webb, John K. Lee, Chung-Chi Milaković, Dinko Dougan, Darren Dzuba, Vladimir A. Flambaum, Victor V. |
| contents | Detecting or placing upper limits on spacetime variations of fundamental constants requires quantifying every potential source of uncertainty. We continue our previous study into the impact of continuum variations on measurements of the fine structure constant, here in the context of quasar absorption systems. An automated (hence objective and reproducible) continuum modelling method is reported in an accompanying paper. We apply the method to the $z_{abs}=1.7975$ absorption system towards the quasar PHL957. Multiple continuum fits are generated, and for each, we derive independent models of the system, each giving its own measurement of the fine structure constant $α$. This process isolates and quantifies the error contribution associated with continuum placement uncertainty. This source of uncertainty, ignored in many previous measurements, arises in two ways: (i) slight local continuum tilt uncertainty generates small line shifts, and (ii) different continuum estimates produce slightly different kinematic structures in the absorption system model. Taking continuum placement uncertainty into account, the new PHL957 measurement we obtain is $Δα/α= -0.53^{+5.45}_{-5.51} \times 10^{-6}$. This measurement assumes terrestrial magnesium isotopic abundances. Recommendations are provided for future $α$ measurements. Finally, we also note the potential importance of the effects identified here for future redshift drift experiments. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2410_00684 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Searching for new physics using high precision absorption spectroscopy; continuum placement uncertainties and $Δα/α$ towards the quasar PHL957 Webb, John K. Lee, Chung-Chi Milaković, Dinko Dougan, Darren Dzuba, Vladimir A. Flambaum, Victor V. Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology Detecting or placing upper limits on spacetime variations of fundamental constants requires quantifying every potential source of uncertainty. We continue our previous study into the impact of continuum variations on measurements of the fine structure constant, here in the context of quasar absorption systems. An automated (hence objective and reproducible) continuum modelling method is reported in an accompanying paper. We apply the method to the $z_{abs}=1.7975$ absorption system towards the quasar PHL957. Multiple continuum fits are generated, and for each, we derive independent models of the system, each giving its own measurement of the fine structure constant $α$. This process isolates and quantifies the error contribution associated with continuum placement uncertainty. This source of uncertainty, ignored in many previous measurements, arises in two ways: (i) slight local continuum tilt uncertainty generates small line shifts, and (ii) different continuum estimates produce slightly different kinematic structures in the absorption system model. Taking continuum placement uncertainty into account, the new PHL957 measurement we obtain is $Δα/α= -0.53^{+5.45}_{-5.51} \times 10^{-6}$. This measurement assumes terrestrial magnesium isotopic abundances. Recommendations are provided for future $α$ measurements. Finally, we also note the potential importance of the effects identified here for future redshift drift experiments. |
| title | Searching for new physics using high precision absorption spectroscopy; continuum placement uncertainties and $Δα/α$ towards the quasar PHL957 |
| topic | Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2410.00684 |