Measuring Mass of Gas in Central Galaxies Using Weak Lensing and Satellite Kinematics in MOND

In Milgrom’s MOdified Newtonian Dynamics (MOND) framework, the dynamical mass of a galaxy is fully determined by its baryonic matter distribution. Using this framework, we fit the distribution of cold and hot gas halos—focusing on the hot gas—around Sloan Digital Sky Survey central galaxies, utilizi...

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Main Authors: Li Ma, Ziwen Zhang, Huiyuan Wang, Xufen Wu
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/adc728
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author Li Ma
Ziwen Zhang
Huiyuan Wang
Xufen Wu
author_facet Li Ma
Ziwen Zhang
Huiyuan Wang
Xufen Wu
author_sort Li Ma
collection DOAJ
description In Milgrom’s MOdified Newtonian Dynamics (MOND) framework, the dynamical mass of a galaxy is fully determined by its baryonic matter distribution. Using this framework, we fit the distribution of cold and hot gas halos—focusing on the hot gas—around Sloan Digital Sky Survey central galaxies, utilizing weak lensing signals from the DECaLS survey. The central galaxies are classified into the total sample and the star-forming sample. Hot gas halo densities nearly follow Plummer’s profile for both samples across all mass bins out to extended radii. We then demonstrate the rotation curves of the galaxy samples. Furthermore, the stellar fraction, M _* /( M _* + M _g ), is between 0.3 and 0.8 in all mass bins of the star-forming sample, which is higher than in the total sample. Additionally, we use the satellite kinematics method in MOND to verify our findings from the weak lensing method. We find good agreement between the two methods, indicating that weak lensing signals reliably measure the dynamical mass of central galaxies and can constrain the distribution of missing baryons in galaxy clusters. Combining both methods, we discover a baryonic mass to line-of-sight velocity dispersion of satellites ( M _b – σ _s ) relation. More sophisticated models, such as Osipkov–Merritt anisotropy profiles, were found unnecessary, as simple isotropic or mildly radially anisotropic MOND models align well with the observed M _b – σ _s relation. Moreover, the isotropic model remains consistent with this relation even when considering external fields from large-scale structures.
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spelling doaj-art-3b39c365e9154d6abeadb7dc97091ecb2025-08-20T03:52:16ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01984210110.3847/1538-4357/adc728Measuring Mass of Gas in Central Galaxies Using Weak Lensing and Satellite Kinematics in MONDLi Ma0https://orcid.org/0009-0005-7751-7280Ziwen Zhang1https://orcid.org/0000-0002-9272-5978Huiyuan Wang2https://orcid.org/0000-0002-4911-6990Xufen Wu3https://orcid.org/0000-0002-1378-8082Department of Astronomy, University of Science and Technology of China , Hefei 230026, People’s Republic of China ; xufenwu@ustc.edu.cn; School of Astronomy and Space Science, University of Science and Technology of China , Hefei 230026, People’s Republic of ChinaDepartment of Astronomy, University of Science and Technology of China , Hefei 230026, People’s Republic of China ; xufenwu@ustc.edu.cn; School of Astronomy and Space Science, University of Science and Technology of China , Hefei 230026, People’s Republic of ChinaDepartment of Astronomy, University of Science and Technology of China , Hefei 230026, People’s Republic of China ; xufenwu@ustc.edu.cn; School of Astronomy and Space Science, University of Science and Technology of China , Hefei 230026, People’s Republic of ChinaDepartment of Astronomy, University of Science and Technology of China , Hefei 230026, People’s Republic of China ; xufenwu@ustc.edu.cn; School of Astronomy and Space Science, University of Science and Technology of China , Hefei 230026, People’s Republic of ChinaIn Milgrom’s MOdified Newtonian Dynamics (MOND) framework, the dynamical mass of a galaxy is fully determined by its baryonic matter distribution. Using this framework, we fit the distribution of cold and hot gas halos—focusing on the hot gas—around Sloan Digital Sky Survey central galaxies, utilizing weak lensing signals from the DECaLS survey. The central galaxies are classified into the total sample and the star-forming sample. Hot gas halo densities nearly follow Plummer’s profile for both samples across all mass bins out to extended radii. We then demonstrate the rotation curves of the galaxy samples. Furthermore, the stellar fraction, M _* /( M _* + M _g ), is between 0.3 and 0.8 in all mass bins of the star-forming sample, which is higher than in the total sample. Additionally, we use the satellite kinematics method in MOND to verify our findings from the weak lensing method. We find good agreement between the two methods, indicating that weak lensing signals reliably measure the dynamical mass of central galaxies and can constrain the distribution of missing baryons in galaxy clusters. Combining both methods, we discover a baryonic mass to line-of-sight velocity dispersion of satellites ( M _b – σ _s ) relation. More sophisticated models, such as Osipkov–Merritt anisotropy profiles, were found unnecessary, as simple isotropic or mildly radially anisotropic MOND models align well with the observed M _b – σ _s relation. Moreover, the isotropic model remains consistent with this relation even when considering external fields from large-scale structures.https://doi.org/10.3847/1538-4357/adc728Galaxy dynamicsModified Newtonian dynamicsMissing massWeak gravitational lensingGalaxy rotation curves
spellingShingle Li Ma
Ziwen Zhang
Huiyuan Wang
Xufen Wu
Measuring Mass of Gas in Central Galaxies Using Weak Lensing and Satellite Kinematics in MOND
The Astrophysical Journal
Galaxy dynamics
Modified Newtonian dynamics
Missing mass
Weak gravitational lensing
Galaxy rotation curves
title Measuring Mass of Gas in Central Galaxies Using Weak Lensing and Satellite Kinematics in MOND
title_full Measuring Mass of Gas in Central Galaxies Using Weak Lensing and Satellite Kinematics in MOND
title_fullStr Measuring Mass of Gas in Central Galaxies Using Weak Lensing and Satellite Kinematics in MOND
title_full_unstemmed Measuring Mass of Gas in Central Galaxies Using Weak Lensing and Satellite Kinematics in MOND
title_short Measuring Mass of Gas in Central Galaxies Using Weak Lensing and Satellite Kinematics in MOND
title_sort measuring mass of gas in central galaxies using weak lensing and satellite kinematics in mond
topic Galaxy dynamics
Modified Newtonian dynamics
Missing mass
Weak gravitational lensing
Galaxy rotation curves
url https://doi.org/10.3847/1538-4357/adc728
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