Signature of an Intermediate-Mass Black Hole in the Central Molecular Zone of Our Galaxy

TL;DR

This study presents evidence for an intermediate-mass black hole in the Galactic Center by analyzing the kinematics of a molecular cloud, revealing a gravitational influence consistent with a ~10^5 solar mass black hole.

Contribution

The paper provides observational evidence linking a molecular cloud's velocity structure to the presence of an intermediate-mass black hole in our galaxy's center.

Findings

Detected a compact, high-velocity molecular cloud with broad velocity width.

Estimated the mass and energy of the cloud, indicating a gravitational influence.

Suggests the presence of an intermediate-mass black hole based on kinematic data.

Abstract

We mapped the high-velocity compact cloud CO-0.40-0.22 in 21 molecular lines in the 3 mm band using the Nobeyama Radio Observatory 45 m radio telescope. Eighteen lines were detected from CO-0.40-0.22. The map of each detected line shows that this cloud has a compact appearance (d=~3 pc) and extremely broad velocity width (DV=~100 km/s). The mass and kinetic energy of CO-0.40-0.22 are estimated to be 10^{3.6} M_sun and 10^{49.7} erg, respectively. The representative position-velocity map along the major axis shows that CO-0.40-0.22 consists of an intense region with a shallow velocity gradient and a less intense high-velocity wing. Here, we show that this kinematical structure can be attributed to a gravitational kick to the molecular cloud caused by an invisible compact object with a mass of ~10^5 M_sun. Its compactness and the absence of counterparts at other wavelengths suggest that this massive object is an intermediate-mass black hole.