Evidence for anisotropy of cosmic acceleration
By J. Colin, Roya Mohayaee, M. Rameez, S. Sarkar. Astronomy & Astrophysics, 2018
202 citations recorded by the source corpus.
Observations reveal a “bulk flow” in the local Universe which is faster and extends to much larger scales than are expected around a typical observer in the standard ΛCDM cosmology. This is expected to result in a scale-dependent dipolar modulation of the acceleration of the expansion rate inferred from observations of objects within the bulk flow. From a maximum-likelihood analysis of the Joint Light-curve Analysis catalogue of Type Ia supernovae, we find that the deceleration parameter, in addition to a small monopole, indeed has a much bigger dipole component aligned with the cosmic microwave background dipole, which falls exponentially with redshift z: q0 = qm + qd.n̂ exp(-z/S). The best fit to data yields qd = −8.03 and S = 0.0262 (⇒d ∼ 100 Mpc), rejecting isotropy (qd = 0) with 3.9σ statistical significance, while qm = −0.157 and consistent with no acceleration (qm = 0) at 1.4σ. Thus the cosmic acceleration deduced from supernovae may be an artefact of our being non-Copernican observers, rather than evidence for a dominant component of “dark energy” in the Universe.
Subfields: Astronomy and Astrophysics
View Paper: https://www.semanticscholar.org/paper/3954c477679c5b50d804aafbd9bcd9db2683e49b
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Astronomy and Astrophysics
Citations in the corpus
- Probing cosmic isotropy with a new X-ray galaxy cluster sample through the LX–T scaling relation (2020, background): “…of distant radio sources (Condon 1988; Blake & Wall 2002; Singal 2011; Rubart & Schwarz 2013; Tiwari & Nusser 2016; Bengaly et al. 2018, 2019; Colin et al. 2019), gamma-ray bursts (Řípa & Shafieloo 2017; Andrade et al. 2019), peculiar velocities of galaxy clusters (Kashlinsky et al. 2008,…”
- A Test of the Cosmological Principle with Quasars (2020, background): “In fact, as observed in our heliocentric frame, the inferred acceleration is essentially a dipole aligned approximately with the local bulk flow of galaxies and towards the CMB dipole (Colin et al. 2019), so cannot be due to a cosmological constant.”
- The Pantheon+ Analysis: Cosmological Constraints (2022, background): “Previous analyses of the first Pantheon sample (e.g., Andrade et al. 2018; Brownsberger et al. 2019; Colin et al. 2019; Soltis et al. 2019) typically search for radial or hemispherical residuals across the sky.”