The Second Galactic Center Black Hole?; A Possible Detection of Ionized Gas Orbiting around an IMBH embedded in the Galactic Center IRS13E complex

Abstract

The Galactic Center is the nuclear region of the nearest spiral galaxy, Milky Way, and contains the supermassive black hole with M~4x10^6 Msun, Sagittarius A* (Sgr A*). One of basic questions about the Galactic Center is whether Sgr A* alone exists as a "massive" black hole in the region or not. The IRS13E complex is a very intriguing IR object which contains a large dark mass comparable to the mass of an intermediate mass black hole (IMBH) from the proper motions of the main member stars. However, the existence of the IMBH remains controversial. There are some objections to accepting the existence of the IMBH. In this study, we detected ionized gas with a very large velocity width (Delta v_{FWZI} ~ 650 km/s) and a very compact size (~400 AU) in the complex using ALMA. We also found an extended component connecting with the compact ionized gas. The properties suggest that this would be an ionized gas flow on the Keplerian orbit with high eccentricity. The enclosed mass is estimated to be 10^4 Msun by the analysis of the orbit. The mass does not conflict with the upper limit mass of the IMBH around Sgr A* which is derived by the long-term astrometry with VLBA. In addition, the object probably has an X-ray counterpart. Consequently, a very fascinated possibility is that the detected ionized gas is rotating around an IMBH embedded in the IRS13E complex.

19 pages, 4 figures, 1 table, accepted for publication in APJL

References in corpus (4)

• The Two Young Star Disks in the Central Parsec of the Galaxy: Properties, Dynamics and Formation
• An Improved Distance and Mass Estimate for Sgr A* from a Multistar Orbit Analysis
• A Catalog of X-ray Point Sources from Two Megaseconds of Chandra Observations of the Galactic Center
• The Discovery of Radio Stars within 10 arcseconds of Sgr A* at 7mm

Cited by in corpus (15)

• Kinematic Structure of the Galactic Center S-cluster
• Indication of Another Intermediate-mass Black Hole in the Galactic Center
• The Fifth Candidate for an Intermediate-mass Black Hole in the Galactic Center
• Hunting for wandering massive black holes
• Colliding Winds in and around the Stellar Group IRS 13E at the Galactic Center
• The influence of the secular perturbation of an intermediate-mass companion: I. Eccentricity excitation of disk stars at the Galactic center
• ALMA Detection of Extreme Blue-Shifted Ionized Gas Within 0.2 pc of Sgr A* from -480 to -300 km/s
• Detection of a dense group of hyper-compact radio sources in the central parsec of the Galaxy
• On Detecting Nearby Nano-Hertz Gravitational Wave Sources via Pulsar Timing Arrays
• The Evaporating Massive Embedded Stellar Cluster IRS 13 Close to Sgr A*. II. Kinematic structure
• Trigonometric parallax and proper motion of Sagittarius A* measured by VERA using the new broad-band back-end system OCTAVE-DAS
• ALMA Astrometry of the Objects within 0.5 pc of Sagittarius A${}^{\ast }$
• Identification of Intermediate-mass Black Hole Candidates Among a Sample of Sd Galaxies
• Compact stellar systems hosting an intermediate mass black hole: magnetohydrodynamic study of inflow-outflow dynamics
• Photometric Constraints on Intermediate-mass Black Holes in the Galactic Centre