Anisotropic Hubble Expansion in Pantheon+ Supernovae
R. McConville, and E. Colgáin. (2023)cite arxiv:2304.02718Comment: 4 pages, 7 figures. Comments welcome.
Abstract
We decompose the Pantheon+ Type Ia supernovae (SN) sample in hemispheres on
the sky finding angular variations up to $4$ km/s/Mpc in the Hubble constant
$H_0$ both in the SH0ES redshift range $0.0233 < z < 0.15$ and in the extended
redshift range $0.01 < z < 0.7$. We assume the $Łambda$CDM model, so our
findings become model dependent in extended redshift ranges. $H_0$ is larger in
a hemisphere encompassing the CMB dipole direction. The variations we see
exceed the errors on the recent SH0ES determination, $H_0 = 73.04 1.04$
km/s/Mpc, but are not large enough to explain early versus late Universe
discrepancies in the Hubble constant. The removal of low redshift SN leads to a
weakening of angular $H_0$ variations, but we confirm that they persist beyond
the influence of the Shapley supercluster $z > 0.06$
Description
Anisotropic Hubble Expansion in Pantheon Supernovae
%0 Generic
%1 mcconville2023anisotropic
%A McConville, Ruairí
%A Colgáin, Eoin Ó
%D 2023
%K tifr
%T Anisotropic Hubble Expansion in Pantheon+ Supernovae
%U http://arxiv.org/abs/2304.02718
%X We decompose the Pantheon+ Type Ia supernovae (SN) sample in hemispheres on
the sky finding angular variations up to $4$ km/s/Mpc in the Hubble constant
$H_0$ both in the SH0ES redshift range $0.0233 < z < 0.15$ and in the extended
redshift range $0.01 < z < 0.7$. We assume the $Łambda$CDM model, so our
findings become model dependent in extended redshift ranges. $H_0$ is larger in
a hemisphere encompassing the CMB dipole direction. The variations we see
exceed the errors on the recent SH0ES determination, $H_0 = 73.04 1.04$
km/s/Mpc, but are not large enough to explain early versus late Universe
discrepancies in the Hubble constant. The removal of low redshift SN leads to a
weakening of angular $H_0$ variations, but we confirm that they persist beyond
the influence of the Shapley supercluster $z > 0.06$
@misc{mcconville2023anisotropic,
abstract = {We decompose the Pantheon+ Type Ia supernovae (SN) sample in hemispheres on
the sky finding angular variations up to $4$ km/s/Mpc in the Hubble constant
$H_0$ both in the SH0ES redshift range $0.0233 < z < 0.15$ and in the extended
redshift range $0.01 < z < 0.7$. We assume the $\Lambda$CDM model, so our
findings become model dependent in extended redshift ranges. $H_0$ is larger in
a hemisphere encompassing the CMB dipole direction. The variations we see
exceed the errors on the recent SH0ES determination, $H_0 = 73.04 \pm 1.04$
km/s/Mpc, but are not large enough to explain early versus late Universe
discrepancies in the Hubble constant. The removal of low redshift SN leads to a
weakening of angular $H_0$ variations, but we confirm that they persist beyond
the influence of the Shapley supercluster $z > 0.06$},
added-at = {2023-04-07T09:28:14.000+0200},
author = {McConville, Ruairí and Colgáin, Eoin Ó},
biburl = {https://www.bibsonomy.org/bibtex/25e1397222c73c80681f5ea2d7ec9473f/citekhatri},
description = {Anisotropic Hubble Expansion in Pantheon Supernovae},
interhash = {704ba15efe4bf667f9be779213b60368},
intrahash = {5e1397222c73c80681f5ea2d7ec9473f},
keywords = {tifr},
note = {cite arxiv:2304.02718Comment: 4 pages, 7 figures. Comments welcome},
timestamp = {2023-04-07T09:28:14.000+0200},
title = {Anisotropic Hubble Expansion in Pantheon+ Supernovae},
url = {http://arxiv.org/abs/2304.02718},
year = 2023
}