Three-dimensional Analysis of the Minispiral at the Galactic Center: Orbital Parameters, Periods, and the Mass of the Black Hole
Abstract
In this paper we simultaneously fit the orbits and line-of-sight velocities of the ionized gas around the supermassive black hole, Sagittarius A* (Sgr A*), at the center of the Milky Way. The data we use are taken with the K-band Multi Object Spectrograph (KMOS), presented in Feldmeier-Krause et al., and cover the central ∼2 pc of the Milky Way. From the brightest gas emission line in the K-band, the Brγ line, we derive the spatial distribution and line-of-sight velocities of the gas in the minispiral. Using the flux distribution and the line-of-sight velocity information, we perform a fit to the three main gas streamers in the minispiral, the Northern Arm, Eastern Arm, and Western Arc, using a Bayesian modeling method, and are able to reconstruct the three-dimensional orbits of these gas streamers. With the best-fit orbital parameters and the measured line-of-sight velocities, we constrain the mass of Sgr A*. The orbit of the Eastern Arm is the one that is best constrained using our data. It gives a best-fit orbital period of ${17.4}_{-11.6}^{+31.0}\times {10}^{3}$ yr and results in an enclosed mass of ${14.9}_{-10.4}^{+69.4}\times {10}^{6}{M}_{\odot }.$
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2020
- DOI:
- 10.3847/1538-4357/ab8ea8
- arXiv:
- arXiv:2004.13707
- Bibcode:
- 2020ApJ...896...68N
- Keywords:
-
- H II regions;
- Galactic center;
- 694;
- 565;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 14 pages, 12 figures, 2 tables. Accepted for publication in ApJ