Measuring the Speed of Light with Updated Hubble Diagram of High-redshift Standard Candles

Liu, Yuting; Cao, Shuo; Biesiada, Marek; Lian, Yujie; Liu, Xiaolin; Zhang, Yilong

doi:10.3847/1538-4357/acc7a5

Cited by 4 publications

(1 citation statement)

References 91 publications

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“…Given the above, six parameters define the current (today, at time 𝑡 = 𝑡 0 ) state of the model universe in terms of its expansion rate, mass components, initial density fluctuations and curvature (see [15]): The Hubble-Lemaitre constant 𝐻 0 ≈ 67.4 ± 0.5 km s −1 Mpc −1 , the baryon density parameter Ω b,0 ≈ 0.05, the dark matter density parameter Ω c,0 ≈ 0.26 (leading to the matter density 3Variations of the fundamental constants are being searched for, see [13] for a recent review. See also [14] for a suggestion to measure the possible variation of 𝑐.…”

Section: Pos(corfu2022)231mentioning

confidence: 99%

The many tensions with dark-matter based models and implications on the nature of the Universe

Kroupa,

Gjergo,

Asencio

et al. 2023

Proceedings of Corfu Summer Institute 2022 "School and Workshops on Elementary Particle Physics and Gravity" — PoS(CORFU2022)

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Section: Pos(corfu2022)231mentioning

confidence: 99%

The many tensions with dark-matter based models and implications on the nature of the Universe

Kroupa,

Gjergo,

Asencio

et al. 2023

Proceedings of Corfu Summer Institute 2022 "School and Workshops on Elementary Particle Physics and Gravity" — PoS(CORFU2022)

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A millisecond pulsar position determined to 0.2 mas precision with VLBI

Ding,

Deller,

Freire

et al. 2024

A&A

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Precise millisecond pulsar (MSP) positions determined with very long baseline interferometry (VLBI) hold the key to building the connection between the kinematic and dynamic reference frames respectively used for VLBI and pulsar timing. A frame connection would provide an important pathway to examining the planetary ephemerides used in pulsar timing, and would potentially enhance the sensitivities of the pulsar timing arrays used to detect stochastic gravitational-wave background in the nano-Hz regime. We aim to significantly improve the precision of the VLBI-based MSP position (from $ at present) by reducing the two dominant components in the positional uncertainty --- the propagation-related uncertainty and the uncertainty resulting from the frequency-dependent core shifts of the reference sources. We introduce a new differential astrometry strategy called PINPT (Phase-screen Interpolation plus frequeNcy-dePendent core shifT correction; pronounced ``pinpoint''), which entails the use of multiple calibrators observed at several widely separated frequencies. The strategy allows determination of the core shift and mitigates the impact of residual delay in the atmosphere. We implemented the strategy on an MSP that is well constrained astrometrically with VLBI and pulsar timing. Using the PINPT strategy, we determined core shifts for four AGNs around and derived a VLBI-based pulsar position with uncertainties of 0.17\,mas and 0.32\,mas in Right Ascension and Declination, respectively, approaching the uncertainty level of the best-determined timing-based MSP positions. Additionally, incorporating the new observations into historical ones, we refined the pulsar proper motion and the parallax-based distance to the $ level and the subparsec level, respectively. The realization of the PINPT strategy promises a factor-of-five positional precision enhancement (over conventional VLBI astrometry) for all kinds of compact radio sources observed at $ including most fast radio bursts.

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Measuring the speed of light with cosmological observations: current constraints and forecasts

Santos,

Bengaly,

Morais

et al. 2024

J. Cosmol. Astropart. Phys.

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We measure the speed of light with current observations, such as Type Ia Supernova, galaxy ages, radial BAO mode, as well as simulations of forthcoming redshift surveys and gravitational waves as standard sirens. By means of a Gaussian Process reconstruction, we find that the precision of such measurements can be improved from roughly 6% and to about 2–2.5% when the gravitational wave simulations are considered, and to 1.5–2% when redshift survey are included in the analysis as well. This result demonstrates that we will be able to perform a cosmological measurement of a fundamental physical constant with significantly improved precision, which will help us underpinning if its value is truly consistent with local measurements, as predicted by the standard model of Cosmology.

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Measuring the Speed of Light with Updated Hubble Diagram of High-redshift Standard Candles

Cited by 4 publications

References 91 publications

The many tensions with dark-matter based models and implications on the nature of the Universe

The many tensions with dark-matter based models and implications on the nature of the Universe

A millisecond pulsar position determined to 0.2 mas precision with VLBI

Measuring the speed of light with cosmological observations: current constraints and forecasts

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