New evidence of the connection between supermassive black holes and the galaxies that host them

The galaxy NGC 1068 with its active galactic nucleus (Image NASA/JPL-Caltech)
The galaxy NGC 1068 with its active galactic nucleus (Image NASA/JPL-Caltech)

An article published in the journal “Nature Astronomy” describes a research about the relationship between Active Galactic Nuclei (AGNs) and the galaxies that host them. Cristina Ramos Almeida of the Instituto de Astrofísica de Canarias (IAC) and Claudio Ricci of the Institute of Astronomy of the Universidad Católica de Chile used data collected by various space and ground-based telescopes to understand the effect of that activity, called in jargon AGN feedback, which can manifest in different ways, favoring or inhibiting star formation in their galaxies.

Active Galactic Nuclei are powered by supermassive black holes that heat powders and gases around them so they emit large amounts of electromagnetic radiation even at very high energies. They can be extremely light sources that can be detected even at distances of billions of light years and are called quasars.

Studies on Active Galactic Nuclei made tremendous progress through the increasingly powerful and at the same time sensitive instruments built in the last few decades. In fact, Cristina Ramos Almeida and Claudio Ricci tried to better understand the influence of Active Galactic Nuclei on the galaxies that host them with a research based on data collected in recent years by the Canarias Grand Telescope, the Very Large Array Interferometer (VLTI) and the NuSTAR, Swift and Suzaku space telescopes.

However, the various studies on the subject have even recently provided apparently contradictory results such as the article published in the journal “Astronomy & Astrophysics”, which described a remarkable star formation in galaxies with hyper-luminous quasars while an article published in the journal “The Astrophysical Journal” described a research that suggests that in early galaxies of the type called dusty starburst the star formation activity can be inhibited by the presence of a quasar.

The analysis of X-ray and infrared observations confirms the close connection between nuclei and galaxies given by gas flows both inward and outward. In short, it’s a direct connection, not just a gravitational influence by the supermassive black hole. There’s also a life phase in which some galaxies consume their own materials because of their Active Galactic Nucleus and were compared to cannibals.

This research is a great step forward in understanding the relationship between galaxies and Active Galactic Nuclei but there are still many details to understand. Claudio Ricci explained that the new generation of infrared and X-ray instruments will greatly contribute to our understanding of nuclei materials.

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