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Estimating the Mass of the Milky Way Galaxy
EP30688
Poster Title: Estimating the Mass of the Milky Way Galaxy
Submitted on 27 Sep 2019
Author(s): Celeste Artiga, Yilun Ma, Ayla Weitz, Alex Ye (Mentor)
Affiliations: ULAB, UC BERKELEY
This poster was presented at undergraduate research symposium
Poster Views: 60
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Poster Information
Abstract: Previous studies on mass estimation have been
conducted using this method, yet we are using a different group of stars in the disk to test
the consistency of the model and the estimation.
For the purpose of this project, we took advantage of the precision of Gaia Data
Release 2’s astrometric measurements. Velocity distributions for stars constrained in rings
of width 1 kpc, deemed r-bins, were then obtained. Using emcee, Markov Chain
Monte-Carlo (MCMC) simulations were implemented on the distribution in each r-bin to
fit an escape velocity curve. In the end, we used the escape velocity derived for each r-bin
and Newtonian mechanics to make a rough estimation of the Milky Way’s mass. Our
findings of a relatively constant escape velocity at different radii hints at the presence of
dark matter.
Summary: Estimating the mass of the Milky Way puts into perspective how a galaxy’s mass can
contribute to its evolution. To carry out such a process could be challenging as we are
observing from within; however, with the Gaia satellite, we now can estimate mass of the
Milky Way using escape velocities
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Katz, D., Antoja, T., Romero-Gómez, M., Drimmel, R., Reylé, C., Seabroke, G. M., ... & Poggio, E.
(2018). Gaia Data Release 2-Mapping the Milky Way disc kinematics. Astronomy & Astrophysics,
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Monari, G., Famaey, B., Carrillo, I., Piffl, T., Steinmetz, M., Wyse, R. F., ... & Janssen, K. (2018). The
escape speed curve of the Galaxy obtained from Gaia DR2 implies a heavy Milky Way. Astronomy &
Astrophysics, 616, doi: 10.1051/0004-6361/201833748
Smith, M. C., Ruchti, G. R., Helmi, A., & Wyse, R. F. (2006). The RAVE Survey: Constraining the
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137-137. doi: 10.1017/s1743921306005692
Karachentsev, I. D., & Makarov, D. I. (1996). Orbital velocity of the Sun and the apex of the Galacti
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