The engines at the centres of galaxies.
From Seyferts within tens of Mpc to bright quasars at cosmological distances, CELESTE gives observers spatial access to the regions where supermassive black holes shape their hosts.
Imagery · ESO
Key Science Topic
Active galactic
Active galactic
nuclei.
Resolving the inner parsecs of nearby active nuclei — the scale on which accretion, radiative feedback, and the launching of relativistic jets all unfold.
An active galactic nucleus is a supermassive black hole accreting matter at a rate high enough to outshine its entire host galaxy. The energy released — radiative, kinetic, and mechanical — couples to the surrounding interstellar medium and regulates the growth of the galaxy over cosmic time. Black-hole feedback is now understood to be a central ingredient in the co-evolution of galaxies and their nuclei, yet it remains poorly resolved spatially in all but the very nearest sources.
At twelve-milliarcsecond resolution, CELESTE reaches projected scales of a few parsecs in nearby active galaxies, and approaches the broad-line region itself for the brightest sources. This is the regime in which models of disk structure, outflow launching, and dust-torus geometry can finally be tested against resolved imagery rather than inferred from integrated light.
The Brief
i.
Science Objectives
Resolve the central engines of nearby AGN at the spatial scale of the broad-line region. Map the geometry of accretion disks and the launching surfaces of outflows. Distinguish radiative feedback from kinetic feedback in the inner host galaxy, and test the unified model of AGN morphologies at sub-parsec precision.
ii.
Observables & Measurements
High-contrast visible-light imaging of the nuclear continuum and surrounding emission-line regions in nearby Seyfert galaxies and low-luminosity AGN. Reverberation-mapped photometric monitoring of variable continuum sources, simultaneous with ground-based optical spectroscopy.
iii.
Key Functional Requirements
Diffraction-limited imaging at 0.4 – 1.0 μm with stable photometric calibration over multi-hour integrations. Coronagraphic suppression of the bright nuclear point source to reveal extended emission. Repeated revisit cadence (days to weeks) for reverberation campaigns.
iv.
CELESTE Uniqueness
CELESTE reaches AGN nuclear regions at a spatial resolution roughly four times sharper than Hubble in the visible — and operates at wavelengths where ground AO is otherwise unable to deliver the diffraction limit. The coronagraphic mode isolates faint extended structure adjacent to extremely bright nuclei, a measurement no current visible-light facility can make.