Black hole winds are no longer what they used to be Astrophysics

Black hole winds are no longer what they used to be

In the early times of the universe, black holes in the centers of active galaxies grew much faster than today. Only in this way it can be explained that 500 to thousand million years after the big bang there were already such huge black holes. Today, however, things look different - the black holes at the centers are evolving in parallel with their host galaxies. When and why did this change occur? That's what a study led by three researchers from Italy's National Institute of Astrophysics (INAF) in Trieste has found, published in the journal Nature. The work is…
Two pairs of quasars in the early universe Astrophysics

Two pairs of quasars in the early universe

Quasars are loners. This is not because they do not get along with their colleagues, but has something to do with their nature. They are nuclei of active galaxies. And every galaxy has only one nucleus. Billions of stars can rotate badly around several cores. Nevertheless, astronomers have now found two quasar pairs at a distance of about ten billion light years as they report in Nature Astronomy. (more…)
Quasar transmits from the early days of the universe Astrophysics

Quasar transmits from the early days of the universe

In the 1950s, astronomers discovered radio sources to which point-like, i.e. star-like objects could be assigned in the visible light range. Until then, whole galaxies had been identified as radio sources. The findings were called "quasi-stellar objects", or quasars for short. Later, however, researchers realized that quasars are embedded in galaxies after all, and in fact constitute their active nuclei radiating in many wavelength ranges. That they had been seen only as point sources was simply because they are very, very distant. In fact, they are the most distant objects in the universe that we can observe. This is…
Premature birth? The most distant quasar raises questions Astrophysics

Premature birth? The most distant quasar raises questions

Astronomers have discovered the most distant quasar yet. The monstrous celestial object called J0313-1806, which existed 670 million years after the Big Bang, shines thousands of times brighter than the Milky Way and is powered by another extreme, the earliest supermassive black hole, more than 1.6 billion times the mass of the Sun. This fully formed distant quasar with a redshift of z = 7.64, formed more than 13 billion years ago, is also the earliest quasar discovered to date, giving astronomers a glimpse of how massive galaxies formed in the early universe. Quasars, powered by the feeding orgies…
Dark energy changes over time Space

Dark energy changes over time

Dark energy is thought to be the reason why the universe continues to expand faster and faster, instead of contracting. Yet researchers still don’t have a well-founded theory on what exactly this mysterious form of energy is. If current theories of the universe are correct, dark energy must account for up to 72 percent of the total matter of the universe today. But what about in the past? Current theory assumes that dark energy had little influence early on. So, the expansion of the universe must have changed significantly over time. Now, with the help of NASA’s Chandra X-ray…
A cosmic beacon from the dawn of the universe Space

A cosmic beacon from the dawn of the universe

The Hubble Space Telescope has succeeded in imaging an especially bright quasar from the dawn of the universe. As astronomers report in a paper, J043947.08+163415.7 is 12.8 billion light-years away. That also means that we can see 12.8 billion years into the past. When the light that is reaching us today was emitted from the quasar, the universe was still in its epoch of reionization. (more…)
How do microquasars work? Space

How do microquasars work?

Quasars are active galactic nuclei. Markarian 231, for example, consists of a pair of ultra-massive black holes that have masses of 4 and 150 million solar masses, orbiting each other at an enormous speed at a distance of 600 million light-years from our Solar System and emitting electromagnetic radiation in the whole spectrum. The brightest objects in the universe are too far away to study them in high resolution. Therefore, astronomers were excited about the discovery of microquasars. What proper quasars present at the scale of whole galaxies, microquasars mimic at the scale of a solar system. (more…)