The Dark Matter Content of Milky Way Dwarf Spheroidal Galaxies: Draco, Sextans, and Ursa Minor

Abstract The Milky Way Survey of the Dark Energy Spectroscopic Instrument (DESI) has so far observed three classical dwarf spheroidal galaxies (dSphs): Draco, Sextans, and Ursa Minor. Based on the observed line-of-sight velocities and metallicities of their member stars, we apply the axisymmetric Jeans Anisotropic Multi-Gaussian Expansion modeling (JAM) approach to recover their inner dark matter distributions. In particular, both the traditional single-population Jeans model and the multiple population chemodynamical model are adopted. With the chemodynamical model, we divide member stars of each dSph into metal-rich and metal-poor populations. The metal-rich populations are more centrally concentrated and dynamically colder, featuring lower velocity dispersion profiles than the metal-poor populations. We find a diversity of the inner density slopes γ of dark matter halos, with the best constraints by the single-population or chemodynamical models consistent with each other. The inner density slopes are <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>0.7</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.35</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.34</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>0.2</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>6</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.12</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.22</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> , and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>0.3</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.16</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.20</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> for Draco, Sextans, and Ursa Minor, respectively. We also present the measured astrophysical J and D factors of the three dSphs. Our results indicate that the study of the dark matter content of dSphs through stellar kinematics is still subject to uncertainties behind both the methodology and the observed data, through comparisons with previous measurements and datasets.

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Journal
The Astrophysical Journal
Published
2025-11-10
DOI
https://doi.org/10.3847/1538-4357/ae07ce
Citations
2
Primary Topic
Stellar, planetary, and galactic studies
Type
article
Field-Weighted Citation Impact
2.31

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article

The Dark Matter Content of Milky Way Dwarf Spheroidal Galaxies: Draco, Sextans, and Ursa Minor

Songting Li, R. R. Joyce, Rongpu Zhou, G. E. Medina et al.
2 citations
The Astrophysical Journal
Stellar, planetary, and galactic studies
2.31
article

The Dark Matter Content of Milky Way Dwarf Spheroidal Galaxies: Draco, Sextans, and Ursa Minor

Songting Li, R. R. Joyce, Rongpu Zhou, G. E. Medina, Ting S. Li, N. Palanque‐Delabrouille, Gregory Tarlé, Constance M. Rockosi, Jiaxin Han, Laurent Le Guillou, David Sprayberry, Alexander H. Riley, David J. Schlegel, Ignasi Pérez-Ràfols, Axel de la Macorra, Martin Landriau, Ling Zhu, Gaston Gutierrez, Alma Xochitl Gonzalez Morales, J. Aguilar, J. Guy, Eusebio Sanchez, Satya Gontcho A Gontcho, Namitha Kizhuprakkat, ENRIQUE GAZTAÑAGA, K. Honscheid, Joseph Harry Silber, Arjun T. Dey, J. E. Forero-Romero, Steven P. Ahlen, Andrew P. Cooper, Aaron Meisner, Sergey E. Koposov, Theodore S. Kisner, Carles G. Palau, David H. Brooks, Monica Valluri, Mustapha Ishak, Wenting Wang, Rui Shi, Robert Kehoe, Hu Zou, Ofer Lahav, Anthony Kremin, Benjamin A. Weaver, P. Doel, Ramon Miquel, Simone Ferraro, Francisco Prada, T. Claybaugh, Michael Schubnell, Graziano Rossi, Hao Yang
article en
2 citations

Abstract

Abstract The Milky Way Survey of the Dark Energy Spectroscopic Instrument (DESI) has so far observed three classical dwarf spheroidal galaxies (dSphs): Draco, Sextans, and Ursa Minor. Based on the observed line-of-sight velocities and metallicities of their member stars, we apply the axisymmetric Jeans Anisotropic Multi-Gaussian Expansion modeling (JAM) approach to recover their inner dark matter distributions. In particular, both the traditional single-population Jeans model and the multiple population chemodynamical model are adopted. With the chemodynamical model, we divide member stars of each dSph into metal-rich and metal-poor populations. The metal-rich populations are more centrally concentrated and dynamically colder, featuring lower velocity dispersion profiles than the metal-poor populations. We find a diversity of the inner density slopes γ of dark matter halos, with the best constraints by the single-population or chemodynamical models consistent with each other. The inner density slopes are <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>0.7</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.35</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.34</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>0.2</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>6</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.12</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.22</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> , and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>0.3</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.16</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.20</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> for Draco, Sextans, and Ursa Minor, respectively. We also present the measured astrophysical J and D factors of the three dSphs. Our results indicate that the study of the dark matter content of dSphs through stellar kinematics is still subject to uncertainties behind both the methodology and the observed data, through comparisons with previous measurements and datasets.

The Astrophysical JournalVol. 993(2)
Boston University (US), Institució Catalana de Recerca i Estudis Avançats (ES), Universidad Complutense de Madrid (ES), Centre National de la Recherche Scientifique (FR), Universidad de Guanajuato (MX), Fermi National Accelerator Laboratory (US), Institute of Space Sciences (ES), Lawrence Berkeley National Laboratory (US), State Street (United States) (US), Universidad de Los Andes (CO), The University of Texas at Dallas (US), Southern Methodist University (US), Shanghai Jiao Tong University (CN), University of California, Santa Cruz (US), University of Toronto (CA), Institute for High Energy Physics (ES), Durham University (GB), Chinese Academy of Sciences (CN), University of Cambridge (GB), National Tsing Hua University (TW), Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR), Université Paris-Saclay (FR), University of Michigan (US), Shanghai Astronomical Observatory (CN), Sejong University (KR), Sorbonne Université (FR), Institut d'Estudis Espacials de Catalunya (ES), Laboratoire de Physique Nucléaire et de Hautes Énergies (FR), Royal Observatory (GB), CEA Paris-Saclay (FR), Institut National de Physique Nucléaire et de Physique des Particules (FR), Community Science and Data Center (US), NSF NOIRLab (US), Instituto de Astrofísica de Andalucía (ES), National Astronomical Observatories (CN), Institut de Recherche sur les Lois Fondamentales de l'Univers (FR), Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (ES), University College London (GB), The Ohio State University (US), University of Portsmouth (GB), Universidad Nacional Autónoma de México (MX), University of California, Berkeley (US), Universitat Politècnica de Catalunya (ES), University of Edinburgh (GB)
National Science Foundation, U.S. Department of Energy, Gordon and Betty Moore Foundation, National Energy Research Scientific Computing Center, National Natural Science Foundation of China, Shanghai Jiao Tong University, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Higher Education Discipline Innovation Project, Office of Science, Science and Technology Facilities Council, Agencia Estatal de Investigación, Division of Astronomical Sciences
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Stellar, planetary, and galactic studies
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