Instead of considering our Galaxy as a disc with a density directly dependent on the distance from the center of the Galaxy, the objective of this study is to propose a new method that will rely on a N-body simulation and a non-axisymmetric and fully baryonic mass model of our Galaxy. There are a lot of existing N-body simulations of our Galaxy about kinematics, as, for example, [1]. This is the first N-body simulation that allows to retrieve the rotation curves of the Milky Way, to retrieve the rotational speeds with a static model. This approach allows us to see the contribution of each arm to the rest of the Galaxy and to understand the flatness of the rotational curves between 10 and 15 kpc from the center of our Galaxy: the inner arm helps to accelerate the rotational motion, as the outer arm will decelerate it, but always lower than the acceleration brought by the inner arm.
References
[1]
Fux, R., Martinet, L. and Pfenniger, D. (1996) 3D N-Body Simulations of the Milky Way. In: Blitz, L. and Teuben, P., Eds., Unsolved Problems of the Milky Way, Springer, 125-131. https://doi.org/10.1007/978-94-009-1687-6_16
[2]
Conselice, C.J., Wilkinson, A., Duncan, K. and Mortlock, A. (2016) The Evolution of Galaxy Number Density at z < 8 and Its Implications. TheAstrophysicalJournal, 830, Article 83. https://doi.org/10.3847/0004-637x/830/2/83
[3]
Loveday, J. (1996) The APM Bright Galaxy Catalogue. MonthlyNoticesoftheRoyalAstronomicalSociety, 278, 1025-1048. https://doi.org/10.1093/mnras/278.4.1025
[4]
Rubin, V.C., Thonnard, N. and Ford Jr., W.K. (1978) Extended Rotation Curves of High-Luminosity Spiral Galaxies. IV—Systematic Dynamical Properties, SA through Sc. TheAstrophysicalJournal, 225, L107. https://doi.org/10.1086/182804
[5]
Jiao, Y., Hammer, F., Wang, H., Wang, J., Amram, P., Chemin, L., et al. (2023) Detection of the Keplerian Decline in the Milky Way Rotation Curve. Astronomy&Astrophysics, 678, A208. https://doi.org/10.1051/0004-6361/202347513
[6]
Milgrom, M. (1983) A Modification of the Newtonian Dynamics as a Possible Alternative to the Hidden Mass Hypothesis. TheAstrophysicalJournal, 270, 365-370. https://doi.org/10.1086/161130
[7]
Kroupa, P., Pawlowski, M. and Milgrom, M. (2012) The Failures of the Standard Model of Cosmology Require a New Paradigm. InternationalJournalofModernPhysicsD, 21, Article ID: 1230003. https://doi.org/10.1142/s0218271812300030
[8]
Famaey, B. and McGaugh, S.S. (2012) Modified Newtonian Dynamics (MOND): Observational Phenomenology and Relativistic Extensions. LivingReviewsinRelativity, 15, Article No. 10. https://doi.org/10.12942/lrr-2012-10
[9]
Feng, J.Q. (2020) Rotating Disk Galaxies without Dark Matter Based on Scientific Reasoning. Galaxies, 8, Article 9. https://doi.org/10.3390/galaxies8010009
[10]
Feng, J.Q. and Gallo, C.F. (2015) Deficient Reasoning for Dark Matter in Galaxies. PhysicsInternational, 6, 11-22. https://doi.org/10.3844/pisp.2015.11.22
[11]
Feng, J. and Gallo, C. (2014) Mass Distribution in Rotating Thin-Disk Galaxies According to Newtonian Dynamics. Galaxies, 2, 199-222. https://doi.org/10.3390/galaxies2020199
[12]
Feng, J.Q. and Gallo, C.F. (2011) Modeling the Newtonian Dynamics for Rotation Curve Analysis of Thin-Disk Galaxies. ResearchinAstronomyandAstrophysics, 11, 1429-1448. https://doi.org/10.1088/1674-4527/11/12/005
[13]
Marmet, L. (2012) Rotation Dynamics of a Galaxy with a Double Mass Distribution. arXiv: 1210.1998. http://arxiv.org/abs/1210.1998
[14]
Ghosh, A., Rai, S. and Gupta, A. (1988) A Possible Servomechanism for Matter Distribution Yielding Flat Rotation Curves in Spiral Galaxies. AstrophysicsandSpaceScience, 141, 1-7. https://doi.org/10.1007/bf00641910
[15]
Coquery, E. and Blanchard, A. (2025) Cosmological Implications of the GAIA Milky Way Declining Rotation Curve. Astronomy&Astrophysics, 703, A88. https://doi.org/10.1051/0004-6361/202556337
[16]
Portail, M., Gerhard, O., Wegg, C. and Ness, M. (2016) Dynamical Modelling of the Galactic Bulge and Bar: The Milky Way’s Pattern Speed, Stellar and Dark Matter Mass Distribution. MonthlyNoticesoftheRoyalAstronomicalSociety, 465, 1621-1644. https://doi.org/10.1093/mnras/stw2819
[17]
Abuter, R., Amorim, A., Baub？ck, M., Berger, J.P., Bonnet, H., Brandner, W., et al. (2019) A Geometric Distance Measurement to the Galactic Center Black Hole with 0.3% Uncertainty. Astronomy&Astrophysics, 625, L10. https://doi.org/10.1051/0004-6361/201935656
[18]
Maíz-Apellániz, J. (2001) The Spatial Distribution of O–B5 Stars in the Solar Neighborhood as Measured by Hipparcos. TheAstronomicalJournal, 121, 2737-2742. https://doi.org/10.1086/320399
[19]
Pr？a, A., Harmanec, P., Torres, G., Mamajek, E., Asplund, M., Capitaine, N., et al. (2016) Nominal Values for Selected Solar and Planetary Quantities: IAU 2015 Resolution B3. The Astronomical Journal, 152, Article 41. https://doi.org/10.3847/0004-6256/152/2/41
[20]
Borrero, Z., et al. (2005) Earth Science: Geology, the Environment, and the Universe. The McGraw-Hill Companies, Inc.
[21]
Li, X., Yang, P., Wang, H., Li, Q., Luo, Y., Luo, Z., et al. (2024) Asymmetric Drift Map of the Milky Way Disk Populations between 8-16 kpc with LAMOST and Gaia Datasets. The Open Journal of Astrophysics, 7. https://doi.org/10.33232/001c.117594
[22]
Dehnen, W., McLaughlin, D.E. and Sachania, J. (2006) The Velocity Dispersion and Mass Profile of the Milky Way. Monthly Notices of the Royal Astronomical Society, 369, 1688-1692. https://doi.org/10.1111/j.1365-2966.2006.10404.x
[23]
Khoperskov, S., Gerhard, O., Di Matteo, P., Haywood, M., Katz, D., Khrapov, S., et al. (2020) Hic Sunt Dracones: Cartography of the Milky Way Spiral Arms and Bar Resonances with GAIA Data Release 2. Astronomy & Astrophysics, 634, L8. https://doi.org/10.1051/0004-6361/201936645
[24]
Bovy, J. and Rix, H. (2013) A Direct Dynamical Measurement of the Milky Way’s Disk Surface Density Profile, Disk Scale Length, and Dark Matter Profile at 4 kpc ？ R ？ 9 kpc. The Astrophysical Journal, 779, Article 115. https://doi.org/10.1088/0004-637x/779/2/115
[25]
Miyamoto, M. and Nagai, R. (1975) Three-Dimensional Models for the Distribution of Mass in Galaxies. Publications of the Astronomical Society of Japan, 27, 533-543. https://doi.org/10.1093/pasj/27.4.533
[26]
Athanassoula, E. (2005) On the Nature of Bulges in General and of Box/Peanut Bulges in Particular: Input from N-Body Simulations. MonthlyNoticesoftheRoyalAstronomicalSociety, 358, 1477-1488. https://doi.org/10.1111/j.1365-2966.2005.08872.x
[27]
Liang, Z.Z., Wang, J., Gao, H., Ho, L.C. and Athanassoula, E. (2025) Connection between Nonaxisymmetric Structures and Neutral Gas Distribution in Disk Galaxies. TheAstrophysicalJournal, 983, Article 61. https://doi.org/10.3847/1538-4357/ad87f1
