The centres of massive galaxies are among the most exotic regions in the Universe. They harbour supermassive black holes, with masses of at least one million, and reaching thousands of millions of times the mass of the Sun. These black holes can cause a great deal of matter to fall towards them, producing the emission of huge quantities of energy before they finally fall into the black hole. Also, during this period (the "active phase" of the galaxy, referred to as an AGN or Active Galactic Nucleus) matter is expelled from outside the black hole in the form of high velocity (relativistic) jets, which can produce violent shocks with the surrounding matter. For some time it has been thought that all of this emission of radiation and particles, and the growth of the black hole itself, should influence the way in which these galaxies form stars, making this star formation more difficult. If this is the case it will allow us to explain observed relations such as that between the mass of the central black hole and the total stellar mass, or understand the found differences between simulations and observations regarding the number of galaxies at a given mass. However, until now, there has been no observational evidence in favour of this idea which has become increasingly well-known and established. Here, we analyse the spectra of the centres of 74 galaxies using data from the Hobby-Eberly Telescope Massive Galaxy Survey with the aim of finding out how the rate of star formation in these systems has changed during their lifetimes (the so-called "star formation history"). To do this we used codes that allow us to compare the observed spectra with those predicted by models of stellar evolution. In this way we can learn how many stars of different ages there are in each of the observed galaxies. As a result, we find different star formation histories in galaxies with black holes of different masses. Our findings suggest clearly that, in effect, supermassive central black holes can affect the formation of stars throughout the lifetime of the galaxy, and that this effect depends on their masses. According to this analysis, galaxies with more massive black holes in their centres show a faster rate of initial star formation, which gives rise to a more massive back hole which then can slow down the star formation in the galaxy. On the contrary, this process is produced much more slowly in those galaxies that currently harbour less massive black holes, starting with a lower star formation efficiency. In addition, the more recent star formation (during the last 700 million years) is greater for galaxies with less massive black holes. In short, these results offer the first observational evidences confirming the interplay between central supermassive black holes and the star formation in massive galaxies, basic for the understanding of how these systems form and evolve.
Advertised on
It may interest you
-
Thanks to images obtained by the James Webb Telescope (JWST), an international scientific team in which the Instituto de Astrofísica de Canarias (IAC) participates has been able to verify that galaxies in the early universe are usually flat and elongated, and not round or spiral like the nearest galaxies. International research has found, by analysing high-resolution, infrared images of the JWST, that flattened oval disc and tube-shaped galaxies were much more common when the universe was between 600 million and 6 billion years old. In contrast, the nearest galaxies have clearly definedAdvertised on
-
The meeting, which will take place on Friday 1 March at 18:00, is being held on the occasion of the International Day of Women and Girls in Science and International Women's Day. The Museum of Science and the Cosmos, associated with the Instituto de Astrofísica de Canarias (IAC), is hosting the Forum of Women Scientists and Technologists this Friday, with the aim of raising the profile of women in the STEM field and serving as a vocational inspiration for future generations. The event will consist of a round table discussion, which will take place in the Museum's assembly hall at 18:00 andAdvertised on
-
An international piece of research, led by the Instituto de Astrofísica de Canarias (IAC) has found clues to the nature of some of the brightest and hottest stars in our Universe, called blue supergiants. Although these stars are commonly observed, their origin has been an old puzzle that has been debated for several decades. By simulating novel stellar models and analysing a large data sample in the Large Magellanic Cloud, IAC researchers have found strong evidence that most blue supergiants may have formed from the merger of two stars bound in a binary system. The study is published in theAdvertised on