قالب وردپرس درنا توس
Home / Science / How black holes shape galaxies

How black holes shape galaxies



  How Black Holes Form Galaxies
Artistic impression showing how ultrafast winds emanating from a supermassive black hole interact with interstellar matter in the host galaxy and liberate their central regions from the gas. Credit: ESA / ATG medialab

Data from the XMM Newton X-ray Observatory of ESA have shown how supermassive black holes shape their host galaxies with strong winds that sweep away interstellar matter.

In a new study, scientists analyzed XMM-Newton observations of the black hole in the nucleus of an active galaxy known as PG 1

114 + 445 for eight years to show how ultra-fast winds – outflow of gas from the accretion disk – get very close to the black hole interaction with interstellar matter in central parts of the galaxy. These outflows have been discovered earlier but for the first time the new study identifies three phases of their interaction with the host galaxy.

"These winds could explain some surprising relationships that scientists have known for years, but could not explain," said lead author Roberto Serafinelli of the National Institute of Astrophysics in Milan, Italy, who led most of the work in his doctorate. at the University of Rome Tor Vergata.

"For example, we see a correlation between the mass of supermassive black holes and the velocity dispersion of stars in the inner parts of their host galaxies, but there is no reason for the gravitational effect of the black hole." Our study shows for the first time how these winds of black Lochs affect the galaxy on a larger scale and may be the missing link. "

Astronomers previously had two types of X-ray flux effluents emitted by the active galactic nuclei, the dense central regions of galaxies called supermassive blacks Holes are known. The so-called ultrafast outflows (UFOs) of highly ionized gas move at a speed of up to 40 percent of the speed of light and can be observed near the central black hole.

Slower effluents, termed warm absorbers, move at much lower speeds of hundreds of km / s and have similar physical properties to particle density and ionization as the surrounding interstellar matter. It is more likely that these slower discharges will be detected at a greater distance from the galaxy centers.

In the new study, scientists describe a third type of outflow that combines the characteristics of the two previous ones: the speed of a UFO and the physical properties of a warm absorber.

"We believe this is the point where the UFO touches the interstellar matter and sweeps it away like a snowplow," Serafinelli said. "We call this an 'ultrafast discharge' entrained" because the UFO permeates interstellar matter at this stage, comparable to the wind pushing boats in the sea. "

This entrainment occurs ten to one hundred light-years away from the black hole. The UFO gradually pushes interstellar matter away from the central parts of the galaxy, releasing it from gas, and slowing down the accumulation of matter around the supermassive black hole.

While models have predicted this kind of interaction, this is the current study, "In the XMM-Newton data, we can see material at a greater distance from the center of the galaxy that has not yet been disturbed by the inner UFO," said co Author Francesco Tombesi from the University of Rome Tor Vergata and the Goddard Space Flight Center of NASA. "We can also see clouds closer to the black hole near the core of the galaxy, where the UFO has begun to interact with interstellar matter."

This first interaction occurs many years after the UFO left the black hole. However, the energy of the UFO allows the relatively small black hole to strike material far out of gravity.

Scientists believe that supermassive black holes transfer their energy through these outflows into the environment, gradually clearing the center of the galaxy's regions of gas, which could then stop star formation. In fact, galaxies today produce far fewer stars than at the beginning of their evolution.

"This is the sixth time these drains have been discovered," said Serafinelli. "This is all a very new science, these phases of runoff were previously observed separately, but the relationship between them has not been clear so far."

The unprecedented energy resolution of XMM-Newton was the key to distinguishing between the three types of features corresponding to the three types of effluents. In the future, astronomers will be able to observe hundreds of thousands of supermassive black holes with new and more powerful observatories such as ESA's Advanced Telescope for High Energy Astrophysics, Athena, making it easier to detect such outflows. Athena, which will be more than 100 times more sensitive than XMM-Newton, is due to be launched in the early 2030s.

"Finding a source is great, but knowing that this phenomenon is prevalent in the universe would be a real breakthrough," said Norbert Schartel, XMM Newton project scientist at ESA. "Even with XMM-Newton, we may find more such sources in the next decade."

Further data will help to decipher the complex interactions between the supermassive black holes and their host galaxies in detail and explain the decline in star formation that astronomers have observed over billions of years.


Hubble watches a tiny galaxy with a big heart


Further information:
Roberto Serafinelli et al. Multiphase quasarfluid effluents in PG 1114 + 445, Astronomy & Astrophysics (2019). DOI: 10.1051 / 0004-6361 / 201935275

Provided by
European Space Agency




Quote :
How Black Holes Form Galaxies (2019, July 24)
retrieved on July 24, 2019
from https://phys.org/news/2019-07-black-holes-galaxies.html

This document is subject to copyright. Apart from any fair dealings for the purposes of private study or research, no
Part may be reproduced without written permission. The content is provided for informational purposes only.


Source link