Quasars have different characteristics that represent different stages in the origin of these bright objects. Also, despite their brightness, many of them managed to “hide” from astronomers. Quasars are the cores of some highly absorbing galaxies. This phenomenon is due to the rapid expansion of supermassive black holes at their center. Sometimes these bright objects appear to be completely hidden from the astronomers’ eyes by thick clouds and gas.

It is thought that only the “doughnut” of dust and gas surrounding the quasar and its accretion disk, the dust torus, can mask this intense radiation. But the authors of a new paper, published in the Monthly Notices of the Royal Astronomical Society, say that its galaxy can play a big role in the “darkening” of the quasar. A team of scientists from the University of Durham (UK) has discovered that some galaxies completely cover their quasars. The researchers analyzed data from 578 dusty infrared quasars at redshifts z ≈ 1-3. The degree of “eclipse” was compared with the rate of star formation, the size and density of their galaxies. Astronomers have discovered that most of these “dusty” quasars are located in very “compact” and actively forming new stars galaxies with a diameter of no more than three thousand light years.

With a constellation of up to 300 solar eclipses per year, the degree of the eclipse changes and begins to increase dramatically. The team estimates that 10 to 30 percent of quasars in galaxies that produce 300 or more stars each year are “obscured” only by the dust and gas in the galaxy itself. , but from this in the torus-shaped structure. which surrounds the working space. Also, this effect only occurs where the quasar has an active growth process. From this, scientists concluded that, perhaps, the subtypes of quasars are not the result of different origins or other factors, but different levels of evolution of the same thing.

Studying these “hidden” quasars will help scientists understand the relationship between these bright objects and the galaxies that surround them.

source: https://arxiv.org/abs/2310.02330