Astronomers using NASA’s James Webb Space Telescope have discovered a thread-like arrangement of 10 galaxies that existed just 830 million years after the big bang. The 3 million light-year-long structure is anchored by a luminous quasar — a galaxy with an active, supermassive black hole at its core. The team believes the filament will eventually evolve into a massive cluster of galaxies, much like the well-known Coma Cluster in the nearby universe.

“I was surprised by how long and how narrow this filament is,” said team member Xiaohui Fan of the University of Arizona in Tucson. “I expected to find something, but I didn’t expect such a long, distinctly thin structure.”

“This is one of the earliest filamentary structures that people have ever found associated with a distant quasar,” added Feige Wang of the University of Arizona in Tucson, the principal investigator of this program.

This discovery is from the ASPIRE project (A SPectroscopic survey of biased halos In the Reionization Era), whose main goal is to study the cosmic environments of the earliest black holes. In total, the program will observe 25 quasars that existed within the first billion years after the big bang, a time known as the Epoch of Reionization.

“The last two decades of cosmology research have given us a robust understanding of how the cosmic web forms and evolves. ASPIRE aims to understand how to incorporate the emergence of the earliest massive black holes into our current story of the formation of cosmic structure,” explained team member Joseph Hennawi of the University of California, Santa Barbara.

Growing Monsters

Another part of the study investigates the properties of eight quasars in the young universe. The team confirmed that their central black holes, which existed less than a billion years after the big bang, range in mass from 600 million to 2 billion times the mass of our Sun. Astronomers continue seeking evidence to explain how these black holes could grow so large so fast.

“To form these supermassive black holes in such a short time, two criteria must be satisfied. First, you need to start growing from a massive ‘seed’ black hole. Second, even if this seed starts with a mass equivalent to a thousand Suns, it still needs to accrete a million times more matter at the maximum possible rate for its entire lifetime,” explained Wang.

“These unprecedented observations are providing important clues about how black holes are assembled. We have learned that these black holes are situated in massive young galaxies that provide the reservoir of fuel for their growth,” said Jinyi Yang of the University of Arizona, who is leading the study of black holes with ASPIRE.

Webb also provided the best evidence yet of how early supermassive black holes potentially regulate the formation of stars in their galaxies. While supermassive black holes accrete matter, they also can power tremendous outflows of material. These winds can extend far beyond the black hole itself, on a galactic scale, and can have a significant impact on the formation of stars.

“Strong winds from black holes can suppress the formation of stars in the host galaxy. Such winds have been observed in the nearby universe but have never been directly observed in the Epoch of Reionization,” said Yang. “The scale of the wind is related to the structure of the quasar. In the Webb observations, we are seeing that such winds existed in the early universe.”

These results were published in two papers in The Astrophysical Journal Letters on June 29.

The discovery was made by researcher Lorna Culverwell from the Department of Virology at the University of Helsinki. The new species was found amongst mosquito samples collected by Culverwell in summer 2022 in the coastal areas of Finland. One male specimen was identified after examining the genitalia and performing a DNA analysis.

“Only one specimen of this species was found, but I believe it to be unlikely that it would be the only one of its species in Finland,” says Culverwell.

No risk of infection in Finland

According to Culverwell, this discovery is an important addition to the mosquitoes recorded from Finland. Up-to-date knowledge about the different mosquito species and their distributions increases our understanding of which, if any, potential pathogens (e.g. viruses or parasites), the mosquitoes could spread now or in the future.

Culex modestus is known to spread West Nile virus, a flavivirus, in southern Europe, between birds and humans or birds and horses. In most human cases West Nile virus causes a mild infection with symptoms such as fever, headache and muscle pain. In some cases the virus may cause neurological disease. For now, West Nile virus has not been discovered in Finland.

“Finns shouldn’t be concerned about this mosquito discovery at this point. To date, no infections acquired in Finland have been discovered in humans or horses, but this finding is a reminder that we should be aware of which mosquito species are here. Knowing potential mosquito-borne diseases that these species are linked to elsewhere in the world helps us to better investigate how likely it would be for these infections to occur in the future,” says Culverwell.

Warming climate increases the need for insect information

Several mosquitoes in genus Culex maintain West Nile virus in bird populations, including Culex pipiens and Culex modestus. For transmission to humans to occur, usually a mosquito would first have to bite a bird carrying the virus, wait several days for the virus to enter their saliva, and then bite a human when they are infected. Sometimes the virus is inherited from female mosquitoes via their eggs.

“At present it is very unlikely for transmission of the virus to humans or horses as several species are required for a disease transmission cycle to occur. Firstly, there would need to be West Nile virus already present in the local or migratory birds in Finland. No virus has so far been reported, despite small scale screening of birds at some sites in Finland. Secondly, only one specimen of Culex modestus is so far known from one location in Finland. For transmission to occur, larger numbers of mosquitoes would be needed for the possibility of some of them to meet any infected birds, and then survive to bite any humans or horses several days afterwards,” says Culverwell.

Culverwell has collected more than 111,000 mosquito samples in Finland since 2012. According to her, it is uncertain how long Culex modestus has potentially occurred in Finland. It is also still unknown whether the area of discovery has a more established population of Culex modestus mosquitoes.

According to Culverwell, further research is now required on both bird and mosquito populations to assess both the short-term and long-term impacts of the discovery.

“A solid foundation of mosquito research in Finland is important because climate change will likely alter the number of mosquito species in the longer-term. Some may die out, but the chance of species from further south invading Finland will increase if the climate warms and winters become milder. Several species from southern Europe are able to transmit other disease-causing pathogens which are not yet found in Finland, so research should be kept up to maintain an understanding of which pathogens are found where, and whether they are a real or potential risk to human or animal health.”

The nodes in these systems can be separated by more than one kilometer. Since metal wires dissipate electrical signals as heat when transferring data at high speeds, these systems transfer data via fiber-optic cables. Unfortunately, a lot of energy is wasted in the process of converting electrical data into optical data (and back again) as signals are sent from one node to another.

In a study published today in Nature Photonics, researchers at Columbia Engineering demonstrate an energy-efficient method for transferring larger quantities of data over the fiber-optic cables that connect the nodes. This new technology improves on previous attempts to transmit multiple signals simultaneously over the same fiber-optic cables. Instead of using a different laser to generate each wavelength of light, the new chips require only a single laser to generate hundreds of distinct wavelengths of light that can simultaneously transfer independent streams of data.

A simpler, more energy-efficient method for data transfer

The millimeter-scale system employs a technique called wavelength-division multiplexing (WDM) and devices called Kerr frequency combs that take a single color of light at the input and create many new colors of light at the output. The critical Kerr frequency combs developed by Michal Lipson, Higgins Professor of Electrical Engineering and Professor of Applied Physics, and Alexander Gaeta, David M. Rickey Professor of Applied Physics and Materials Science and Professor of Electrical Engineering, allowed the researchers to send clear signals through separate and precise wavelengths of light, with space in between them.

“We recognized that these devices make ideal sources for optical communications, where one can encode independent information channels on each color of light and propagate them over a single optical fiber,” says senior author Keren Bergman, Charles Batchelor Professor of Electrical Engineering at Columbia Engineering, where she also serves as the faculty director of the Columbia Nano Initiative. This breakthrough could allow systems to transfer exponentially more data without using proportionately more energy.

The team miniaturized all of the optical components onto chips roughly a few millimeters on each edge for generating light, encoded them with electrical data, and then converted the optical data back into an electrical signal at the target node. They devised a novel photonic circuit architecture that allows each channel to be individually encoded with data while having minimal interference with neighboring channels. That means the signals sent in each color of light don’t become muddled and difficult for the receiver to interpret and convert back into electronic data.

“In this way, our approach is much more compact and energy-efficient than comparable approaches,” says the study’s lead author Anthony Rizzo, who conducted this work while a PhD student in the Bergman lab and is now a research scientist at the U.S. Air Force Research Laboratory Information Directorate. “It is also cheaper and easier to scale since the silicon nitride comb generation chips can be fabricated in standard CMOS foundries used to fabricate microelectronics chips rather than in expensive dedicated III-V foundries.”

The compact nature of these chips enables them to directly interface with computer electronics chips, greatly reducing the total energy consumption since the electrical data signals only have to propagate over millimeters of distance rather than tens of centimeters.

Bergman noted, “What this work shows is a viable path towards both dramatically reducing the system energy consumption while simultaneously increasing the computing power by orders of magnitude, allowing artificial intelligence applications to continue to grow at an exponential rate with minimal environmental impact.”

Exciting results pave the way to real-world deployment

In experiments, the researchers managed to transmit 16 gigabits per second per wavelength for 32 distinct wavelengths of light for a total single-fiber bandwidth of 512 Gb/s with less than one bit in error out of one trillion transmitted bits of data. These are incredibly high levels of speed and efficiency. The silicon chip transmitting the data measured just 4 mm x 1 mm, while the chip that received the optical signal and converted it into an electrical signal measured just 3 mm x 1 mm — both smaller than a human fingernail.

“While we used 32 wavelength channels in the proof-of-principle demonstration, our architecture can be scaled to accommodate over 100 channels, which is well within the reach of standard Kerr comb designs,” Rizzo adds.

These chips can be fabricated using the same facilities used to make the microelectronics chips found in a standard consumer laptop or cellphone, providing a straightforward path to volume scaling and real-world deployment.

The next step in this research is to integrate the photonics with chip-scale driving and control electronics to further miniaturize the system.

Planets form in a disk around a newborn star. These ‘proto-planetary’ disks only last a few million years, meaning that a forming planetary system only has this amount of time to finish its formation. However, it is still not clear just how rapidly planet formation begins within these disks. Recent ALMA observations have revealed that many proto-planetary disks have substructures such as gaps and rings, indicating that planets are already forming from the disk. “These previous results motivated us to examine even younger disks around protostars to answer the question, at what stage of star formation do planet forms,” says Nagayoshi Ohashi at Academia Sinica Institute of Astronomy and Astrophysics (ASIAA, Taiwan), who led the team.

The team observed disks around 19 protostars located within about 650 light-years from the Earth. This is the first systematic study to investigate the detailed structure of disks around a large sample of protostars with high angular resolution. The observations clearly show that the disks around protostars are different from more-evolved proto-planetary disks. Among the 19 protostars, rings, and gaps, which are signs of planet formation, were observed only in a few disks. Moreover, the ring structures are less distinct than those seen in the proto-planetary disks.

“We did not expect to see such clear differences between disks around protostars and more-evolved disks,” says Ohashi. John Tobin, a Co-PI of the program at the National Radio Astronomical Observatory (USA) adds “Our results suggest that disks around protostars are not fully ready for planet formation. We believe that the actual formation of the planetary system progresses rapidly in the 100,000 years to 1,000,000 years after star formation begins.”