Dual quasars observed blazing away in the centre of merging galaxies
Galaxies grow and evolve by merging with other galaxies, a process which can cause the supermassive black holes at their centres to become so luminous they’re thousands of times brighter than the entire galaxy (these are known as quasars).
While astronomers have observed many merging galaxies with more than one quasar in our own cosmic neighbourhood, more distant examples are extremely challenging to find. Now, astronomers have detected the first pair of closely bound quasars from when the Universe was only three billion years old – a period of intense star formation called “cosmic noon”.
The quasars are only 10,000 light-years apart and their original host galaxies are likely well on their way to becoming a single giant elliptical galaxy.
“The confirmation process wasn’t easy and we needed an array of telescopes covering the spectrum from X-rays to the radio to finally confirm that this system is indeed a pair of quasars, instead of, say, two images of a gravitationally lensed quasar,” says Yue Shen, Assistant Professor of Astronomy at the University of Illinois in the US, and co-author of the study in the journal Nature.
“We don’t see a lot of double quasars at this early time. And that’s why this discovery is so exciting,” adds lead author Yu-Ching Chen, a PhD candidate at the University of Illinois.
“Knowing about the progenitor population of black holes will eventually tell us about the emergence of supermassive black holes in the early Universe, and how frequent those mergers could be.”
Time-released drugs might make missed meds a thing of the past
Missing crucial doses of medicines is a huge problem in the treatment of chronic disease, but this could be avoided by encapsulating medicine in microparticles that dissolve and release drugs over time.
Researchers have developed a new technology called PULSED (Particles Uniformly Liquified and Sealed to Encapsulate Drugs) to produce biodegradable polymer shells small enough to be injected with standard hypodermic needles.
In a new study in Advanced Materials, they showed that they could tweak the polymer recipe to vary how quickly the particles dissolved to release the drug – from as little as 10 days to almost five weeks.
The process of sealing these kinds of particles has previously proven so difficult that the cost of production was considered impractical for many applications. But the team developed a new contactless method that overcomes this hurdle; this involves suspending the microparticles above a hot plate so that the top of the particle melts and self-seals, while the bottom of the particle remains intact.
New membrane mirrors for large space-based telescopes
A researcher has developed a new way to produce and shape large, high quality mirrors that are much thinner than the ones previously used in space telescopes, according to a new study in Applied Optics.
“Launching and deploying space telescopes is a complicated and costly procedure,” says Sebastian Rabien from Max Planck Institute for Extraterrestrial Physics in Germany, author of the paper.
“This new approach — which is very different from typical mirror production and polishing procedures — could help solve weight and packaging issues for telescope mirrors, enabling much larger, and more sensitive,telescopes to be placed in orbit.”
The fabrication involves chemical vapour deposition, in which a precursor material is evaporated and thermally split into single molecules, which are then deposited on the surface of rotating liquid inside a vacuum chamber, and then combine to form a polymer membrane.
“Although this work only demonstrated the feasibility of the method, it lays the groundwork for larger packable mirror systems that are less expensive,” says Rabien.
“It could make lightweight mirrors that are 15 or 20 meters in diameter a reality, enabling space-based telescopes that are orders of magnitude more sensitive than ones currently deployed or being planned.”
These crabs chow down on crown-of-thorns starfish
University of Queensland scientists have identified natural predators which could help fight outbreaks of the coral-eating crown-of-thorns starfish (COTS) on the Great Barrier Reef.
According to a new study in Coral Reefs, the researchers tested more than 100 species of crabs, shrimps, worms, snails, and small fishes and found one that was a standout at eating juvenile COTS.
“The red decorator crab – or Schizophrys aspera – was by far the most consistent predator consuming COTS in 89 per cent of the feeding trials,” says first author Amelia Desbiens, a PhD candidate from UQ’s School of Biological Sciences, Australia.
“We were surprised by its voracity – each red decorator crab devoured more than five COTS per day while most other species barely ate a single one.
It had previously been suspected that the presence of specific predators could explain why some reefs escape COTS outbreaks, but the specific predators and their rates of predation in COTS had not been well understood.