Supermassive black hole feeding and feedback observed on subparsec scales.

Active galaxies contain a supermassive black hole at their center that grows by accreting matter from the surrounding galaxy. The accretion process in about the central 10 parsecs has not been directly resolved in previous observations because of the small apparent angular sizes involved. We observed the active nucleus of the Circinus Galaxy using submillimeter interferometry. A dense inflow of molecular gas was evident on subparsec scales. We calculated that less than 3% of this inflow is accreted by the black hole, with the rest being ejected by multiphase outflows, providing feedback to the host galaxy. Our observations also reveal a dense gas disk surrounding the inflow that is gravitationally unstable, which drives the accretion into about the central 1 parsec.

Spatial correlation between submillimetre and Lyman-alpha galaxies in the SSA 22 protocluster.

Lyman-alpha emitters are thought to be young, low-mass galaxies with ages of approximately 10(8) yr (refs 1, 2). An overdensity of them in one region of the sky (the SSA 22 field) traces out a filamentary structure in the early Universe at a redshift of z approximately 3.1 (equivalent to 15 per cent of the age of the Universe) and is believed to mark a forming protocluster. Galaxies that are bright at (sub)millimetre wavelengths are undergoing violent episodes of star formation, and there is evidence that they are preferentially associated with high-redshift radio galaxies, so the question of whether they are also associated with the most significant large-scale structure growing at high redshift (as outlined by Lyman-alpha emitters) naturally arises. Here we report an imaging survey of 1,100-microm emission in the SSA 22 region. We find an enhancement of submillimetre galaxies near the core of the protocluster, and a large-scale correlation between the submillimetre galaxies and the low-mass Lyman-alpha emitters, suggesting synchronous formation of the two very different types of star-forming galaxy within the same structure at high redshift. These results are in general agreement with our understanding of the formation of cosmic structure.