Speaker
Description
Compact obscured nuclei (CONs) represent one of the most extreme and least understood phases of nuclear activity in nearby luminous infrared galaxies. Powered by either deeply buried active galactic nuclei or extremely compact starbursts, these systems provide a unique laboratory for studying the simultaneous onset of nuclear fueling and feedback during rapid galaxy evolution. Their high column densities render them opaque at optical and near-infrared wavelengths, but their submillimetre emission offers a direct window into their embedded central regions.
We present high-resolution multi-band ALMA observations of the CON IRAS 17578-0400, combining continuum and molecular line data in Bands 3, 5, 6, and 7 to resolve the nuclear region on parsec scales. The data reveal a compact, dense structure consistent with a rotating molecular dusty disk or torus, supported by the continuum morphology and the kinematics of the 13CO1-0 emission. By comparing continuum properties across ALMA bands, we constrain the radiative characteristics and extreme physical conditions of the parsec-scale nucleus. Using multiple molecular tracers, we further probe the nuclear dynamics and search for signatures of molecular outflows, enabling an estimate of the central dynamical mass and an assessment of whether a deeply embedded supermassive black hole is present.
These observations provide new insight into the structure, kinematics, and feedback processes operating in compact obscured nuclei, highlighting IRAS 17578-0400 as a key example of nuclear activity hidden within dense, dust-enshrouded galaxy cores.