Near- and Mid-infrared Observations in the Inner Tenth of a Parsec of the Galactic Center Detection of Proper Motion of a Filament Very Close to Sgr A*

Abstract

We analyze the gas and dust emission in the immediate vicinity of the supermassive black hole Sgr A* at the Galactic center (GC) with the ESO Very Large Telescope (Paranal/Chile) instruments SINFONI and VISIR. The SINFONI H + K data cubes show several emission lines with related line map counterparts. From these lines, the Br γ emission is the most prominent one and appears to be shaped as a bar extending along the north–south direction. With VISIR, we find a dusty counterpart to this filamentary emission. In this work, we present evidence that this feature could most be likely connected to the minispiral and potentially influenced by the winds of the massive stars in the central cluster or an accretion wind from Sgr A*. To this end, we coadd the SINFONI data between 2005 and 2015. The spectroscopic analysis reveals a range of Doppler-shifted emission lines. We also detect substructures in the shape of clumps that can be investigated in the channel maps of the Br γ bar. In addition, we compare the detection of the near-infrared Br γ feature to PAH1 mid-infrared observations and published 226 GHz radio data. These clumps show a proper motion of about 320 km s −1 that are consistent with other infrared continuum–detected filaments in the GC. Deriving a mass of for the investigated Br γ feature shows an agreement with former derived masses for similar objects. Besides the north–south Br γ bar, we find a comparable additional east–west feature. Also, we identify several gas reservoirs that are located west of Sgr A* that may harbor dusty objects.