Skip to main content

Upper Limit on the Milky Way Mass

This image from the Hubble Space Telescope shows the small galaxy called the Sagittarius dwarf irregular galaxy, or "SagDIG" for short. SagDIG is relatively nearby, and Hubble's sharp vision is able to reveal many thousands of individual stars within the galaxy. Credit: NASA, ESA, and The Hubble Heritage Team STScI/AURA


As one of the most massive Milky Way satellites, the Sagittarius dwarf galaxy has played an important role in shaping the Galactic disk and stellar halo morphologies. The disruption of Sagittarius over several close-in passages has populated the halo of our Galaxy with large-scale tidal streams and offers a unique diagnostic tool for measuring its gravitational potential.

In a recent paper (Dierickx, Loeb 2017) the authors test different progenitor mass models for the Milky Way and Sagittarius by modeling the full infall of the satellite. They constrain the mass of the Galaxy based on the observed orbital parameters and multiple tidal streams of Sagittarius.

This artist's concept depicts the most up-to-date information about the shape of our own Milky Way galaxy. Credits: NASA/JPL-Caltech/R. Hurt (SSC/Caltech)


Their semi-analytic modeling of the orbital dynamics agrees with full N-body simulations, and favors low values for the Milky Way mass, ≤ 1012MSun.


  • Marion I. P. Dierickx, Abraham Loeb - Upper Limit on the Milky Way Mass from the Orbit of the Sagittarius Dwarf Satellite - (arXiv)
Etichette:

Comments

Post a Comment

Popular posts from this blog

A UNIVERSE WITHOUT A CENTER?

Image Credit: Eugenio Bianchi, Carlo Rovelli & Rocky Kolb. According to the standard theories of cosmology, there is no center of the universe. In a conventional explosion, material expand out from a central point and the instinct suggests that with the Big Bang happened something similar. But the Big Bang was not an explosion like that at all: it was an explosion of space, not an explosion in space . The Big Bang happened everywhere in the Universe.
Post a Comment
Read more

A SIGNIFICATIVE FRACTION OF BARYONS RESIDE IN THE FILAMENTS OF THE COSMIC WEB

(Credit: NASA, ESA, and E. Hallman (University of Colorado, Boulder) Observations of the cosmic microwave background indicate that baryons (protons, neutrons, etc., - the ordinary matter just to understand) occupies only 5% of the total energy content of the Universe (95% is dark matter and dark energy). However in the local universe approximately half of this "ordinary" matter it has never been observed.
Post a Comment
Read more

QUASARS AND THE COSMIC REIONIZATION

Credit: NASA/ESA Recently it has been suggested that quasars can be primarily responsible for the reionization of the universe.
Post a Comment
Read more