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Do supernovae indicate an accelerating universe?
- Source :
- Eur.Phys.J.ST, Eur.Phys.J.ST, 2021, 230 (9), pp.2067-2076. ⟨10.1140/epjs/s11734-021-00199-6⟩
- Publication Year :
- 2021
- Publisher :
- Springer Science and Business Media LLC, 2021.
-
Abstract
- In the late 1990's, observations of 93 Type Ia supernovae were analysed in the framework of the FLRW cosmology assuming these to be `standard(isable) candles'. It was thus inferred that the Hubble expansion rate is accelerating as if driven by a positive Cosmological Constant $\Lambda$. This is still the only direct evidence for the `dark energy' that is the dominant component of the standard $\Lambda$CDM cosmological model. Other data such as BAO, CMB anisotropies, stellar ages, the rate of structure growth, etc are all `concordant' with this model but do not provide independent evidence for accelerated expansion. Analysis of a larger sample of 740 SNe Ia shows that these are not quite standard candles, and highlights the "corrections" applied to analyse the data in the FLRW framework. The latter holds in the reference frame in which the CMB is isotropic, whereas observations are made in our heliocentric frame in which the CMB has a large dipole anisotropy. This is assumed to be of kinematic origin i.e. due to our non-Hubble motion driven by local inhomogeneity in the matter distribution. The $\Lambda$CDM model predicts how this peculiar velocity should fall off as the averaging scale is raised and the universe becomes sensibly homogeneous. However observations of the local `bulk flow' are inconsistent with this expectation and convergence to the CMB frame is not seen. Moreover the kinematic interpretation implies a corresponding dipole in the sky distribution of high redshift quasars, which is rejected by observations at 4.9$\sigma$. The acceleration of the Hubble expansion rate is also anisotropic at 3.9$\sigma$ and aligned with the bulk flow. Thus dark energy may be an artefact of analysing data assuming that we are idealised observers in an FLRW universe, when in fact the real universe is inhomogeneous and anisotropic out to distances large enough to impact on cosmological analyses.<br />Comment: 14 pages, 4 figures, 4 tables
- Subjects :
- cosmological model
quasar: redshift
Cosmic microwave background
General Physics and Astronomy
Cosmological constant
Astrophysics
baryon: oscillation: acoustic
01 natural sciences
General Relativity and Quantum Cosmology
Cosmology
High Energy Physics - Phenomenology (hep-ph)
general relativity
Peculiar velocity
General Materials Science
dark energy
010303 astronomy & astrophysics
media_common
supernova: Type I
Physics
Hubble constant
cosmological constant
redshift: high
High Energy Physics - Phenomenology
kinematics
density: perturbation
flow
Robertson-Walker
[PHYS.GRQC]Physics [physics]/General Relativity and Quantum Cosmology [gr-qc]
Computer Science::Mathematical Software
symbols
Baryon acoustic oscillations
expansion: acceleration
Astrophysics - Cosmology and Nongalactic Astrophysics
velocity
density: primordial
Cosmology and Nongalactic Astrophysics (astro-ph.CO)
media_common.quotation_subject
FOS: Physical sciences
General Relativity and Quantum Cosmology (gr-qc)
Astrophysics::Cosmology and Extragalactic Astrophysics
Computer Science::Digital Libraries
temperature: fluctuation
symbols.namesake
0103 physical sciences
structure
Physical and Theoretical Chemistry
010308 nuclear & particles physics
Universe
gravitation
[PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph]
anisotropy: dipole
Dark energy
Einstein
galaxy
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
cosmic background radiation: anisotropy
Hubble's law
Subjects
Details
- ISSN :
- 19516401 and 19516355
- Volume :
- 230
- Database :
- OpenAIRE
- Journal :
- The European Physical Journal Special Topics
- Accession number :
- edsair.doi.dedup.....a373ebf21b6b185ec73783d7d94195f1