Galactic Sun's motion in the Cold Dark Matter, MOdified Newtonian Dynamics and MOdified Gravity scenarios

Abstract

We numerically integrate the equations of motion of the Sun in Galactocentric Cartesian rectangular coordinates for -4.5 Gyr <= t <= 0 in Newtonian mechanics with two different models for the Cold Dark Matter (CDM) halo, in MOdified Newtonian Dynamics (MOND) and in MOdified Gravity (MOG) without resorting to CDM. The initial conditions used come from the latest kinematical determination of the 3D Sun's motion in the Milky Way (MW) by assuming for the rotation speed of the Local Standard of Rest (LSR) the recent value Θ_0=268 km s^-1 and the IAU recommended value Θ_0=220 km s^-1; the Sun is assumed located at 8.5 kpc from the Galactic Center (GC). For Θ_0=268 km s^-1 the birth of the Sun, 4.5 Gyr ago, would have occurred at large Galactocentric distances (12-27 kpc depending on the model used), while for Θ_0=220 km s^-1 it would have occurred at about 8.8-9.3 kpc for almost all the models used. The integrated trajectories are far from being circular, especially for Θ_0=268 km s^-1, and differ each other with the CDM models yielding the widest spatial extensions for the Sun's orbital path.

LaTex2e, 6 pages, 3 figures, 7 tables

References in corpus (9)

• Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
• The Milky Way's Circular Velocity Curve to 60 kpc and an Estimate of the Dark Matter Halo Mass from Kinematics of ~2400 SDSS Blue Horizontal Branch Stars
• Confrontation of MOND with the rotation curves of early-type disc galaxies
• Insight into the baryon-gravity relation in galaxies
• Testing modified gravity with globular cluster velocity dispersions
• Fundamental parameter-free solutions in Modified Gravity
• Milky Way potentials in CDM and MOND. Is the Large Magellanic Cloud on a bound orbit?
• On the "Galactic Habitable Zone"
• An Orbit Fit for the Grillmair Dionatos Cold Stellar Stream