SIMBAD references

2004A&A...426...81P - Astronomy and Astrophysics, volume 426, 81-96 (2004/10-4)

Kinematic and structural analysis of the Minispiral in the Galactic Center from BEAR spectro-imagery.

PAUMARD T., MAILLARD J.-P. and MORRIS M.

Abstract (from CDS):

Integral field spectroscopy of the inner region of the Galactic Center, over a field of roughly 40"x40" was obtained at 2.06µm (HeI) and 2.16µm (Brγ) using BEAR, an imaging Fourier Transform Spectrometer, at spectral resolutions respectively of 52.9km/s and 21.3km/s, and a spatial resolution of ≃0.5". The analysis of the data was focused on the kinematics of the gas flows, traditionally called the ``Minispiral'', concentrated in the neighborhood of the central black hole, Sgr A*. From the decomposition into several velocity components (up to four) of the line profile extracted at each point of the field, velocity features were identified. Nine distinguishable structures are described: the standard Northern Arm, Eastern Arm, Bar, Western Arc, and five additional, coherently-moving patches of gas. From this analysis, the Northern Arm appears not limited, as usually thought, to the bright, narrow North-South lane seen on intensity images, but it consists instead of a weak, continuous, triangular-shaped surface, drawn out into a narrow stream in the vicinity of Sgr A* where it shows a strong velocity gradient, and a bright western rim. The Eastern Arm is split into three components (a Ribbon and a Tip, separated by a cavity, and an elongated feature parallel to the Ribbon: the Eastern Bridge). We also report extinction of some interstellar structures by other components, providing information on their relative position along the line of sight. A system of Keplerian orbits can be fitted to most of the Northern Arm, and the bright rim of this feature can be interpreted in terms of line-of-sight orbit crowding caused by the warping of the flowing surface at the western edge facing Sgr A*. These results lead to a new picture of the gas structures in Sgr A West, in which large-scale gas flows and isolated gas patches coexist in the gravitational field of the central Black Hole. The question of the origin of the ionized gas is addressed and a discussion of the lifetime of these features is presented.

Abstract Copyright:

Journal keyword(s): Galaxy: center - ISM: individual objects: Sgr A West - ISM: kinematics and dynamics - infrared: ISM - Instrumentation: interferometers - line: profiles

VizieR on-line data: <Available at CDS (J/A+A/426/81): fig7a.fit fig7aerr.fit fig7b.fit fig7berr.fit>

Nomenclature: Table 1: [PMM2004] Sgr A West a (Nos a-i).

Simbad objects: 45

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