The weak lensing radial acceleration relation: Constraining modified gravity and cold dark matter theories with KiDS-1000

Journal
Date Issued
2021
Author(s)
Margot M. Brouwer
•
Kyle A. Oman
•
Edwin A. Valentijn
•
Maciej Bilicki
•
Catherine Heymans
•
Henk Hoekstra
•
Nicola R. Napolitano
•
Nivya Roy
•
•
Angus H. Wright
•
Marika Asgari
•
Jan Luca van den Busch
•
Andrej Dvornik
•
Thomas Erben
•
Benjamin Giblin
•
Alister W. Graham
•
Hendrik Hildebrandt
•
Andrew M. Hopkins
•
Arun Kannawadi
•
Konrad Kuijken
•
Jochen Liske
•
HuanYuan Shan
•
Tilman Tröster
•
Erik Verlinde
•
Manus Visser
DOI
Abstract
We present measurements of the radial gravitational acceleration around isolated galaxies, comparing the expected gravitational acceleration given the baryonic matter with the observed gravitational acceleration, using weak lensing measurements from the fourth data release of the Kilo-Degree Survey. These measurements extend the radial acceleration relation (RAR) by 2 decades into the low-acceleration regime beyond the outskirts of the observable galaxy. We compare our RAR measurements to the predictions of two modified gravity (MG) theories: MOND and Verlinde's emergent gravity. We find that the measured RAR agrees well with the MG predictions. In addition, we find a difference of at least $6\sigma$ between the RARs of early- and late-type galaxies (split by S\'{e}rsic index and $u-r$ colour) with the same stellar mass. Current MG theories involve a gravity modification that is independent of other galaxy properties, which would be unable to explain this behaviour. The difference might be explained if only the early-type galaxies have significant ($M_{gas} \approx M_*$) circumgalactic gaseous haloes. The observed behaviour is also expected in $\Lambda$CDM models where the galaxy-to-halo mass relation depends on the galaxy formation history. We find that MICE, a $\Lambda$CDM simulation with hybrid halo occupation distribution modelling and abundance matching, reproduces the observed RAR but significantly differs from BAHAMAS, a hydrodynamical cosmological galaxy formation simulation. Our results are sensitive to the amount of circumgalactic gas; current observational constraints indicate that the resulting corrections are likely moderate. Measurements of the lensing RAR with future cosmological surveys will be able to further distinguish between MG and $\Lambda$CDM models if systematic uncertainties in the baryonic mass distribution around galaxies are reduced.
Volume
650
Start page
A113
Uri
Url
Issn Identifier
0004-6361
Ads BibCode
2021A&A...650A.113B
Rights
open.access
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