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Leiden, Jul 2: Astronomers have discovered a luminous galaxy caught in the act of reionizing its surrounding gas only 800 million years after the Big Bang.

The research, led by Romain Meyer, PhD student at UCL in London, UK, has been presented at the virtual annual meeting of the European Astronomical Society (EAS).

Studying the first galaxies that formed 13 billion years ago is essential to understanding our cosmic origins. One of the current hot topics in extragalactic astronomy is 'cosmic reionization,' the process in which the intergalactic gas was ionized (atoms stripped of their electrons).

Cosmic reionization is similar to an unsolved murder: We have clear evidence for it, but who did it, how and when? We now have strong evidence that hydrogen reionization was completed about 13 billion years ago, in the first billion years of the universe, with bubbles of ionized gas slowly growing and overlapping.

The objects capable of creating such ionized hydrogen bubbles have however remained mysterious until now: the discovery of a luminous galaxy in which 60-100 percent of ionizing photons escape, is likely responsible for ionizing its local bubble. This suggests the case is closer to being solved.

The two main suspects for cosmic reionization are usually 1) a population of numerous faint galaxies leaking ~10 percent of their energetic photons, and 2) an 'oligarchy' of luminous galaxies with a much larger percentage (>50 percent) of photons escaping each galaxy.

In either case, these first galaxies were very different from those today: galaxies in the local universe are very inefficient leakers, with only <2-3 percent of ionizing photons escaping their host. To understand which galaxies governed cosmic reionization, astronomers must measure the so-called escape fractions of galaxies in the reionization era.

The detection of light from excited hydrogen atoms (the so-called Lyman-alpha line) can be used to infer the fraction of escaping photons. On the one hand, such detections are rare because reionization-era galaxies are surrounded by neutral gas which absorbs that signature hydrogen emission.

On the other hand, if this hydrogen signal is detected it represents a 'smoking gun' for a large ionized bubble, meaning we have caught a galaxy reionizing its surroundings. The size of the bubble and the galaxy's luminosity determines whether it is solely responsible for creating this ionized bubble or if unseen accomplices are necessary.

The discovery of a luminous galaxy 800 million years after the Big Bang supports the scenario where an 'oligarchy' of bright leakers emits most of the ionizing photons.

"It is the first time we can point to an object responsible for creating an ionized bubble, without the need for a contribution from unseen galaxies.

Additional observations with the upcoming James Webb Space Telescope will enable us to study further what is likely one of the best suspects for the unsolved case of cosmic reionization," said Meyer.

Claiming that e-commerce giants like Amazon import as much as 80 per cent of the items sold on their platforms, small manufacturers' body has said that their business models do not benefit local industry and are creating jobs of delivery boys only.

"Neither manufacturers nor traders are getting any benefit from the business models of Amazon and Flipkart because they largely import their products from China and Korea and sell here. Nearly 80 per cent of their products are imported," said Anil Bhardwaj, Secretary General, Federation of Indian Micro and Small & Medium Enterprises (FISME).

Bhardwaj said that the global e-commerce players generally source and sell products through their own preferred suppliers and as a result a large number of local manufacturers and traders get crowded out.

He listed out deep discounting and buying products from preferred companies as unfair practices.

"Even if they buy products from local suppliers the commission charged is very high," Bhardwaj said adding that the issues related to unfair practices have been raised with Commerce Ministry on multiple occasions.

FISME maintains that the technology-driven retail is way forward and one cannot be oblivious of the benefits it brings to consumers but at the same time the local industry can also not be ignored given its role in job creation.

"If both traders and local manufacturers are crowded out then how would the local industry survive and employment be generated?" asked Bhardwaj.

As Amazon Founder and CEO Jeff Bezos is currently on his three-day visit to India, the local traders are up in arms against the "unfair" trade practices of the tech giant. Delhi-based Confederation of All India Traders (CAIT) has launched a countrywide protest against the company and has organised protests across 300 cities.

In a setback to Amazon and Walmart-backed Flipkart, the fair market watchdog Competition Commission of India (CCI) has ordered probe into the business operations of both the companies on multiple counts including deep-discounts and exclusive tie-up with preferred sellers.

"For the first time some concrete step has been taken against Amazon and Flipkart who are continuously violating the FDI policy in indulging in a vicious racket of controlling and monopolising not only the e-commerce but even the retail trade as well," CAIT National Secretary General Praveen Khandelwal said after the CCI order.

In a study conducted in 117 countries, researchers have found that the world is experiencing the most dramatic reduction in the seismic noise (the hum of vibrations in the planet's crust) in recorded history due to global COVID-19 lockdowns.

Measured by instruments called seismometers, seismic noise is caused by vibrations within the Earth, which travel like waves and the waves can be triggered by earthquakes, volcanoes, and bombs - but also by daily human activity like travel and industry.

This quiet period was likely caused by the total global effect of social distancing measures, closure of services and industry, and drops in tourism and travel, the study published in the journal Science, reported.

The new research, led by the Royal Observatory of Belgium and five other institutions around the world including Imperial College London (ICL), showed that the dampening of 'seismic noise' caused by humans was more pronounced in more densely populated areas.

"Our study uniquely highlights just how much human activities impact the solid Earth, and could let us see more clearly than ever what differentiates human and natural noise," said study co-author Stephen Hicks from ICL in the UK.

For the findings, the research team looked at seismic data from a global network of 268 seismic stations in 117 countries and found significant noise reductions compared to before any lockdown at 185 of those stations.

Researchers tracked the 'wave' of quietening between March and May as worldwide lockdown measures took hold.

The largest drops in vibrations were seen in the most densely populated areas, like Singapore and New York City, but drops were also seen in remote areas like Germany's the Black Forest and Rundu in Namibia.

Citizen-owned seismometers, which tend to measure more localised noise, noted large drops around universities and schools around Cornwall, UK and Boston, US - a drop in noise 20 per cent larger than seen during school holidays.

The findings showed that countries like Barbados, where lockdown coincided with the tourist season, saw a 50 per cent decrease in noise.

"The changes have also given us the opportunity to listen in to the Earth's natural vibrations without the distortions of human input," the study authors wrote.

Earlier in April, a study published in the journal Nature, reported at least a 30 per cent reduction in that amount of ambient human noise since lockdown began in Belgium.