Evidence For A Jet And Outflow From Sgr A*: A Continuum And Spectral Line Study

We study the environment of Sgr A* using spectral and continuum observations with the Atacama Large Millimeter/submillimeter Array and Very Large Array. Our analysis of subarcsecond H30 alpha, H39 alpha, H52 alpha, and H56 alpha line emission towards Sgr A* confirms the recently published broad-peak similar to 500 km s(-1) spectrum towards Sgr A*. We also detect emission at more extreme radial velocities peaking near -2500 and 4000 km s(-1) within 0.2 arcsec. We then present broad-band radio continuum images at multiple frequencies on scales from arcseconds to arcminutes. A number of elongated continuum structures lie parallel to the Galactic plane, extending from 0.4 arcsec to similar to 10 arcmin. We note a non-thermal elongated structure on an arcminute scale emanating from Sgr A* at low frequencies between 1 and 1.4 GHz where thermal emission from the minispiral is depressed by optical depth effects. The position angle of this elongated structure and the sense of motion of ionized features with respect to Sgr A* suggest a symmetric, collimated jet emerging from Sgr A* with an opening angle of similar to 30 degrees and a position angle of similar to 60 degrees punching through the medium before accelerating a significant fraction of the orbiting ionized gas to high velocities. The jet with an estimated mass flow rate of similar to 1.4 x 10(-5) M-circle dot yr(-1) emerges perpendicular to the equatorial plane of the accretion flow near the event horizon of Sgr A* and runs along the Galactic plane. To explain a number of east-west features near Sgr A*, we also consider the possibility of an outflow component with a wider angle launched from the accretion flow at larger radii.