A dormant overmassive black hole in the early Universe

Summary

A dormant, overmassive black hole was discovered in the early universe, with a mass of approximately 4 x 10^8 M and an accretion rate of only 0.02 times the Eddington limit.

Highlights

• A massive black hole was discovered in a galaxy at z = 6.68.
• The black hole has a mass of approximately 4 x 10^8 M.
• The accretion rate is only 0.02 times the Eddington limit.
• The black hole to host galaxy stellar mass ratio is about 0.4.
• The system is closer to the local relations in terms of dynamical mass and velocity dispersion of the host galaxy.
• The discovery suggests that dormant, overmassive black holes may be common in the early universe.
• The properties of the black hole are consistent with scenarios in which short bursts of super-Eddington accretion have resulted in black hole overgrowth.

Key Insights

• The discovery of a dormant, overmassive black hole in the early universe challenges current understanding of black hole growth and evolution.
• The low accretion rate of the black hole suggests that it may be in a dormant state, with little gas available for accretion.
• The high black hole to host galaxy stellar mass ratio indicates that the black hole has grown more rapidly than the host galaxy.
• The system's proximity to local relations in terms of dynamical mass and velocity dispersion suggests that the host galaxy is already well-formed.
• The discovery highlights the importance of considering selection effects when studying high-redshift AGN.
• The properties of the black hole are consistent with scenarios in which short bursts of super-Eddington accretion have resulted in black hole overgrowth, suggesting that such events may be common in the early universe.
• The finding suggests that dormant, overmassive black holes may be more common than actively accreting AGN in star-forming galaxies.

Mindmap

Citation

Juodžbalis, I., Maiolino, R., Baker, W. M., Tacchella, S., Scholtz, J., D’Eugenio, F., Witstok, J., Schneider, R., Trinca, A., Valiante, R., DeCoursey, C., Curti, M., Carniani, S., Chevallard, J., de Graaff, A., Arribas, S., Bennett, J. S., Bourne, M. A., Bunker, A. J., … Willott, C. (2024). A dormant overmassive black hole in the early Universe. In Nature (Vol. 636, Issue 8043, pp. 594–597). Springer Science and Business Media LLC. https://doi.org/10.1038/s41586-024-08210-5