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${}^{\ast }$ (Sgr A${}^{\ast }$), 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. (2015) and cover the central $\sim$ 2 pc of the Milky Way. From the brightest gas emission line in the K-band, the Br$\gamma$ 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 modelling 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${}^{\ast }$. The orbit of the Eastern Arm is the one that is best constrained using our data. It gives a best-fit orbital period of $17.4_{-11.6}^{+31.0}\cdot 10^3$ years and results in an enclosed mass of $14.9_{-10.4}^{+69.4}\cdot 10^6{M}_{\odot }.$

14 pages, 12 figures, 2 tables. Accepted for publication in ApJ

References in corpus (8)

• An Update on Monitoring Stellar Orbits in the Galactic Center
• An Improved Distance and Mass Estimate for Sgr A* from a Multistar Orbit Analysis
• Dynamics of Ionized Gas at the Galactic Center: VLA Observations of the 3D Velocity Field and Location of the Ionized Streams in Sagittarius A West
• A black-hole mass measurement from molecular gas kinematics in NGC4526
• KMOS view of the Galactic Centre - II. Metallicity distribution of late-type stars
• Recovering the intrinsic shape of early-type galaxies
• Dominant dark matter and a counter rotating disc: MUSE view of the low luminosity S0 galaxy NGC 5102
• Triaxial orbit-based modelling of the Milky Way Nuclear Star Cluster

Cited by in corpus (4)

• Mid-Infrared studies of dusty sources in the Galactic Center
• Regularized 3D spectroscopy with CubeFit: method and application to the Galactic Center Circumnuclear disk
• Mid-infrared extinction toward the Galactic center
• Discovery of a Dense Association of Stars in the Vicinity of the Supermassive Black Hole Sgr A*