Cosmic radio burst traced back to distant dwarf galaxy

A burst of cosmic radio waves has finally been traced back to its source: an old dwarf galaxy located more than 3 billion light years from Earth.

Such bursts are rare and last only briefly, but have been of interest since their first detection almost ten years ago due to their appearance from outside our galaxy.

Fast radio bursts flash for just a few milliseconds and need to be very powerful in order to be observed from Earth. Combined with their origin being outside our galaxy, the fact that none of those originally observed were detected again has led to such bursts causing great interest in the astronomical community.

The Fornax dwarf galaxy, which, like the galaxy responsible for the cosmic radio burst, is significantly smaller than our own Milky Way. Image courtesy of ESO/Digitized Sky Survey 2

A repeating burst discovered in 2012 allowed researchers to monitor its area of the sky with the Karl Jansky Very Large Array (VLA) in New Mexico and the Arecibo radio dish in Puerto Rico.

The development of high-speed data recording and real-time data analysis software by an astronomer at the University of California, Berkeley, allowed the VLA to detect a total of nine bursts over the period of a month last year.

The VLA’s detection pinpointed the burst to within a tenth of an arcsecond, subsequent efforts by larger European and American radio interferometer arrays further narrowed it to within one-hundredth of an arcsecond, within a region about 100 light years in diameter. Deep imaging by the Gemini North Telescope followed and revealed an optically faint dwarf galaxy that the VLA found to continuously emit low-level radio waves.

Image courtesy of Danielle Futselaar (www.artsource.nl)

This emission is typical of a galaxy with an active nucleus perhaps indicative of a central supermassive black hole. It is also noted that extremely bright exploding stars – called superluminous supernovae – and long gamma ray bursts also occur in this type of galaxy. Both such events are believed to be associated with the massive, highly magnetic and rapidly rotating neutron stars called magnetars.

“All these threads point to the idea that in this environment, something generates these magnetars,” said co-author and UC Berkeley astronomer Casey Law.

“It could be created by a superluminous supernova or a long gamma ray burst, and then later on, as it evolves and its rotation slows down a bit, it produces these fast radio bursts as well as continuous radio emission powered by that spindown. Later on in life, it looks like the magnetars we see in our galaxy, which have extremely strong magnetic fields but rotate more like ordinary pulsars.”

Law’s theory is but one, though the new data has ruled out several explanations for the origin of the radio bursts that had previously been offered. Law’s team are the first to observe the bursts as a cosmological phenomenon and where said phenomenon is occurring; the objective now is to figure out the reason for the phenomenon’s occurrence.

Researchers discover remains of “Triassic Jaws” who dominated the seas after Earth’s most severe mass extinction event

Researchers have discovered the fossil remains of an unknown large predatory fish called Birgeria: an approximately 1.8-meter-long primitive bony fish with long jaws and sharp teeth that swallowed its prey whole.

Swiss and US researchers led by the Paleontological Institute and Museum of the University of Zurich say the Birgeria dominated the sea that once covered present-day Nevada one million years after the mass extinction.

Its period of dominance began following “the most catastrophic mass extinction on Earth”, which took place about 252 million years ago – at the boundary between the Permian and Triassic geological periods.

Image courtesy of UZH. Featured image courtesy of Nadine Bösch

Up to 90% of the marine species of that time were annihilated, and before the discovery of the Birgeria, palaeontologists had assumed that the first predators at the top of the food chain did not appear until the Middle Triassic epoch about 247 to 235 million years ago.

“The surprising find from Elko County in northeastern Nevada is one of the most completely preserved vertebrate remains from this time period ever discovered in the United States,” emphasises Carlo Romano, lead author of the study.

Although, species of Birgeria existed worldwide. The most recent discovery belongs to a previously unknown species called Birgeria Americana, and is the earliest example of a large-sized Birgeria species, about one and a half times longer than geologically older relatives.

The researchers say the discovery of Birgeria is proof that food chains recovered quicker than previously thought from Earth’s most devastating mass extinction event.

According to earlier studies, marine food chains were shortened after the mass extinction event and recovered only slowly and stepwise.

However, finds such as the newly discovered Birgeria species and the fossils of other vertebrates now show that so-called apex predators (animals at the very top of the food chain) already lived early after the mass extinction.

“The vertebrates from Nevada show that previous interpretations of past biotic crises and associated global changes were too simplistic,” said Romano.

Revolutionary DNA sunscreen gives better protection the longer its worn

Researchers have developed a ground-breaking sunscreen made of DNA that offers significant improvements over conventional versions.

Unlike current sunscreens, which need to be reapplied regularly to remain effective, the DNA sunscreen improves over time, offering greater protection the longer it is exposed to the sun.

In addition, it also keeps the skin hydrated, meaning it could also be beneficial as a treatment for wounds in extreme or adverse environments.

Developed by researchers from Binghamton University, State University of New York, the innovative sunscreen could prove essential as temperatures climb and many are increasingly at risk of conditions caused by excessive UV exposure, such as skin cancer.

“Ultraviolet (UV) light can actually damage DNA, and that’s not good for the skin,” said Guy German, assistant professor of biomedical engineering at Binghamton University.

“We thought, let’s flip it. What happens instead if we actually used DNA as a sacrificial layer? So instead of damaging DNA within the skin, we damage a layer on top of the skin.”

The DNA sunscreen has the potential to become a standard, significantly improving the safety of spending time in the sun

The research, which is published today in the journal Scientific Reports, involved the development of thin crystalline DNA films.

These films are transparent in appearance, but able to absorb UV light; when the researchers exposed the film to UV light, they found that its absorption rate improved, meaning the more UV is was exposed to, the more it absorbed.

“If you translate that, it means to me that if you use this as a topical cream or sunscreen, the longer that you stay out on the beach, the better it gets at being a sunscreen,” said German.

The film will no doubt attract the attention of sunscreen manufacturers, who will likely be keen to commercialise such a promising product. However, the researchers have not said if there is any interest as yet, and if there is any clear timeline to it becoming a commercial product.

 

The film’s properties are not just limited to sun protection, however. The DNA film can also store water at a far greater rate than conventional skin, limiting water evaporation and increasing the skin’s hydration.

As a result, the film is also being explored as a wound covering, as it would allow the wound to be protected from the sun, keep it moist – an important factor for improved healing – and allow the wound to be monitored without needing to remove the dressing.

“Not only do we think this might have applications for sunscreen and moisturizers directly, but if it’s optically transparent and prevents tissue damage from the sun and it’s good at keeping the skin hydrated, we think this might be potentially exploitable as a wound covering for extreme environments,” said German.