(ORDO NEWS) — Astronomers have found that radiation from the active centers of galaxies is darkened by surrounding dust much more than previously thought.
This means that we also underestimated the strength of the radiation itself, which is created by matter around supermassive black holes.
Active galactic nuclei, with their supermassive black holes absorbing surrounding matter, are perhaps the most powerful stable sources of energy in the Universe.
Some of them radiate much more than all the stars in their galaxies combined. And yet we underestimate their power.
Martin Gaskell and his colleagues at the University of California at Santa Cruz have studied the active core of the galaxy NGC 5548, which is located almost 250 million light-years from us and contains a supermassive black hole with a mass of about 65 million solar masses.
Surrounded by a large cloud of dust, it looks dimmer and reddish, like the Sun at sunset.
The degrees of darkening and “reddening” of the radiation are interrelated and depend on the amount and density of dust.
But if for the setting Sun they can be established, knowing the initial characteristics of its radiation, then for distant black holes such estimates are very difficult.
There are only models that predict how dust affects their radiation in different wavelengths.
Therefore, Gaskell and co-authors used seven different methods at once to calculate the reddening curve of radiation emanating from the center of NGC 5548, and, consequently, its dimming.
In all cases, the scientists obtained results that are in good agreement with each other.
The degree of obscuration turned out to be much higher than previously thought, based on data on the amount of dust in our immediate space environment.
This is especially noticeable in the far ultraviolet region of radiation, the intensity of which drops by an order of magnitude.
According to scientists, NGC 5548 is a fairly typical representative of active galactic nuclei.
If we underestimate the strength of their obscuration by the surrounding dust, then we underestimate the power of radiation emanating from such objects.
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