3D adaptive mesh refinement simulations of the gas cloud G2 born within the disks of young stars in the Galactic Center

TL;DR

This study uses advanced 3D hydrodynamical simulations to investigate the origin and evolution of the gas cloud G2 near the Galactic Center, aiming to match observational data and resolve previous modeling issues.

Contribution

It introduces high-resolution 3D AMR simulations with updated orbital data to better understand G2's properties and origin within young star disks.

Findings

A consistent model explains the observed Brackett-$\gamma$ light curve and position-velocity diagrams.

The initial formation of G2 likely occurred before 1900 within the disks of young stars.

The simulations address previous issues with formation epoch and luminosity evolution.

Abstract

The dusty, ionized gas cloud G2 is currently passing the massive black hole in the Galactic Center at a distance of roughly 2400 Schwarzschild radii. We explore the possibility of a starting point of the cloud within the disks of young stars. We make use of the large amount of new observations in order to put constraints on G2's origin. Interpreting the observations as a diffuse cloud of gas, we employ three-dimensional hydrodynamical adaptive mesh refinement (AMR) simulations with the PLUTO code and do a detailed comparison with observational data. The simulations presented in this work update our previously obtained results in multiple ways: (1) high resolution three-dimensional hydrodynamical AMR simulations are used, (2) the cloud follows the updated orbit based on the Brackett-$\gamma$ data, (3) a detailed comparison to the observed high-quality position-velocity diagrams and the evolution of the total Brackett-$\gamma$ luminosity is done. We concentrate on two unsolved problems of the diffuse cloud scenario: the unphysical formation epoch only shortly before the first detection and the too steep Brackett-$\gamma$ light curve obtained in simulations, whereas the observations indicate a constant Brackett-$\gamma$ luminosity between 2004 and 2013. For a given atmosphere and cloud mass, we find a consistent model that can explain both, the observed Brackett-$\gamma$ light curve and the position-velocity diagrams of all epochs. Assuming initial pressure equilibrium with the atmosphere, this can be reached for a starting date earlier than roughly 1900, which is close to apo-center and well within the disks of young stars.