Monster black holes sometimes lurk behind gas and dust, hiding from the gaze of most telescopes. But they give themselves away when material they feed on emits high-energy X-rays that NASA’s NuSTAR mission can detect. That’s how NuSTAR recently identified two gas-enshrouded supermassive black holes, located at the centers of nearby galaxies.
The first stars appeared about 100 million years after the Big Bang. When the universe was about 3 billion years old, star formation activity peaked at rates about ten times above current levels. Why this happened, and whether the physical processes back then were different from those today, are among the most pressing questions in astronomy.
Astronomers using data from the NASA/ESA Hubble Space Telescope and other observatories have performed an accurate census of the number of galaxies in the universe. The researchers came to the surprising conclusion that the observable universe contains at least two trillion galaxies. The results also help solve an ancient astronomical paradox — why is the sky dark at night?
Quasars are supermassive black holes that sit at the centre of enormous galaxies, accreting matter. They shine so brightly that they are among the most distant objects in the universe that we can currently study. New work from a team led by Carnegie’s Eduardo Bañados has discovered 63 new quasars from when the universe was just 7 percent of its present age.
The processes that cause galaxies to cease star formation are not well understood and constitute an outstanding problem in the study of the evolution of elliptical, spiral (such as the Milky Way) and irregular galaxies. Now, using a large sample of around 70,000 galaxies, a team of researchers may have an explanation for why some stop creating stars.
This new image from the VLT Survey Telescope (VST) at ESO’s Paranal Observatory in Chile captures a spectacular concentration of galaxies known as the Fornax Cluster, which can be found in the Southern Hemisphere constellation of Fornax (The Furnace). The cluster plays host to a menagerie of galaxies of all shapes and sizes, some of which are hiding secrets.
The Stephan’s Quintet of galaxies in the constellation Pegasus was discovered by astronomer Édouard Stephan in 1877. This image combines observations performed at three different wavelengths, with ESA’s Herschel and XMM-Newton space observatories as well as with ground-based telescopes, to reveal the different components of the five galaxies.
Dark matter is an invisible, mysterious substance that makes up about 27 percent of all matter and energy in the universe. A new NASA study publishing this week proposes that when a stream of dark matter particles goes through a planet, the planet’s gravity bends and focuses the particles into an ultra-dense filament, or “hair,” of dark matter. In theory, there should be many such hairs sprouting from Earth.