Anisotropy in Pantheon+ supernovae

Abstract

We employ Maximum Likelihood Estimators to examine the Pantheon+ catalogue of Type Ia supernovae for large scale anisotropies in the expansion rate of the Universe. The analyses are carried out in the heliocentric frame, the CMB frame, as well as the Local Group frame. In all frames, the Hubble expansion rate in the redshift range 0.023 < z < 0.15 is found to have a statistically significant dipolar variation exceeding 1.5 km/s/Mpc, i.e. bigger than the claimed 1% uncertainty in the SH0ES measurement of the Hubble parameter H_0. The deceleration parameter too has a redshift-dependent dipolar modulation at > 5 sigma significance, consistent with previous findings using the SDSSII/SNLS3 Joint Lightcurve Analysis catalogue. The inferred cosmic acceleration cannot therefore be due to a Cosmological Constant, but is likely a general relativistic effect due to the anomalous bulk flow in our local Universe.

Comment: 34 pages, 11 figures, 9 tables; Accepted for publication in EPJ C; Code available on: https://github.com/Shin107/Anisotropy-in-Pantheon-Plus

References in corpus (58)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Array Programming with NumPy
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• The Complete Light-curve Sample of Spectroscopically Confirmed Type Ia Supernovae from Pan-STARRS1 and Cosmological Constraints from The Combined Pantheon Sample
• The Supernova Legacy Survey: Measurement of Omega_M, Omega_Lambda and w from the First Year Data Set
• A Comprehensive Measurement of the Local Value of the Hubble Constant with 1 km/s/Mpc Uncertainty from the Hubble Space Telescope and the SH0ES Team
• Improved cosmological constraints from a joint analysis of the SDSS-II and SNLS supernova samples
• Planck 2018 results. I. Overview and the cosmological legacy of Planck
• The Pantheon+ Analysis: Cosmological Constraints
• Dark Energy Survey Year 1 Results: Cosmological Constraints from Galaxy Clustering and Weak Lensing
• DESI 2024 VI: Cosmological Constraints from the Measurements of Baryon Acoustic Oscillations
• The Pantheon+ Analysis: The Full Dataset and Light-Curve Release
• SALT2: using distant supernovae to improve the use of Type Ia supernovae as distance indicators
• Jerk, snap, and the cosmological equation of state
• A kinematical approach to dark energy studies
• Cosmological parameters from the comparison of peculiar velocities with predictions from the 2M++ density field
• Relativistic cosmology and large-scale structure
• Is the Observable Universe Consistent with the Cosmological Principle?
• Evidence for anisotropy of cosmic acceleration
• Probing the anisotropic local universe and beyond with SNe Ia data
• Does Hubble Tension Signal a Breakdown in FLRW Cosmology?
• A Challenge to the Standard Cosmological Model
• Marginal evidence for cosmic acceleration from Type Ia supernovae
• The effect of peculiar velocities on supernova cosmology
• Probing the isotropy of cosmic acceleration traced by Type Ia supernovae
• The Pantheon+ Analysis: Improving the Redshifts and Peculiar Velocities of Type Ia Supernovae Used in Cosmological Analyses
• Analyzing the Large-Scale Bulk Flow using CosmicFlows4: Increasing Tension with the Standard Cosmological Model
• Hints of FLRW Breakdown from Supernovae
• Measuring cosmic bulk flows with Type Ia Supernovae from the Nearby Supernova Factory
• On Larger $H_0$ Values in the CMB Dipole Direction
• Improved constraints on cosmological parameters from SNIa data
• Constraining dark matter halo properties using lensed SNLS supernovae
• Is the expansion of the universe accelerating? All signs point to yes
• Apparent cosmic acceleration from type Ia supernovae
• Searching for new physics with profile likelihoods: Wilks and beyond
• BAHAMAS: new SNIa analysis reveals inconsistencies with standard cosmology
• Multipole decomposition of the general luminosity distance 'Hubble law' -- a new framework for observational cosmology
• Testing the Cosmological Principle with CatWISE Quasars: A Bayesian Analysis of the Number-Count Dipole
• Peculiar motions, accelerated expansion and the cosmological axis
• Is there really a Hubble tension?
• Is the expansion of the universe accelerating? All signs still point to yes a local dipole anisotropy cannot explain dark energy
• Evaluating bulk flow estimators for CosmicFlows-4 measurements
• The cosmic radio dipole: Bayesian estimators on new and old radio surveys
• Do supernovae indicate an accelerating universe?
• The deceleration parameter in `tilted' Friedmann universes
• The multipole expansion of the local expansion rate
• Testing $\Lambda$CDM cosmology in a binned universe: anomalies in the deceleration parameter
• The deceleration parameter in `tilted' universes: generalising the Friedmann background
• Cosmological foundations revisited with Pantheon+
• Testing the isotropy of cosmic acceleration with Pantheon+ and SH0ES: A cosmographic analysis
• Testing cosmic anisotropy with Pade approximation and Pantheon+ sample
• Large-scale peculiar motions and cosmic acceleration
• Consistency of Pantheon+ supernovae with a large-scale isotropic universe
• A local infall from a cosmographic analysis of Pantheon+
• Approximations for the divergence of the local large-scale structure velocity field and its implications for Tilted Cosmology
• Yet another sample of RFGC galaxies
• Cosmological inference from within the peculiar local universe

Cited by in corpus (8)

• The redshift dependence of the inferred $H_0$ in a local void solution to the Hubble tension
• Testing anisotropic Hubble expansion
• Anisotropy in the cosmic acceleration inferred from supernovae
• Horndeski in motion
• Measuring cosmic dipole with the GRB luminosity-time relation
• Testing the cosmological principle on gigaparsec scales
• Expected redshift drift for tilted observers
• A Quantitative Framework for Testing the Hubble Tension in a Bianchi Type I Cosmological Background