A UK-led team of astronomers reports today (August 4th) in Nature that they have tracked down an elusive population of black holes growing rapidly hidden behind clouds of dust. Their results suggest that most black hole growth takes place in dusty galaxies, solving astronomer’s headaches, as until now, the cosmic x-ray background suggested the existence of more growing black holes than they could find.
Growing black holes, known as quasars, are some of the brightest objects in the Universe and are seen by the light emitted as gas and dust spiral into the black hole. Quasars are situated in the inner-most regions of galaxies and can consume the equivalent mass of between ten and a thousand stars in one year! Astronomers believe that all quasars are surrounded by a dusty ring which hides them from sight on Earth in about half of cases.
However, examining the cosmic x-ray background, which is made up primarily of the emissions from quasars, astronomers realised that there should be many more obscured quasars than currently known. Objects surrounded by dust are hard to see with visible light, so the astronomers looked at infrared wavelengths, which are less likely to be reflected away. Using NASA’s Spitzer Space Telescope’s First Look Data, they were able to find a new population of obscured quasars. The new quasars have no spectra that can be seen and are thought to be hidden behind the dust of the galaxy itself rather than just a dust ring. The presence of lots of dust in a galaxy indicates that stars are still forming there. The researchers found 21 examples of these lost quasars in a relatively small patch of sky. All of the objects were confirmed as quasars by the National Radio Astronomy Observatorys Very Large Array radio telescope, New Mexico, and the Particle Physics and Astronomy Research Councils William Hershel Telescope on La Palma.
Tracking movement of immune cells identifies key first steps in inflammatory arthritis
23.01.2017 | Massachusetts General Hospital
Team discovers how bacteria exploit a chink in the body's armor
20.01.2017 | University of Illinois at Urbana-Champaign
For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.
According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
24.01.2017 | Earth Sciences
24.01.2017 | Life Sciences
24.01.2017 | Physics and Astronomy