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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.

Washington D.C., Jan 12: A recent study has claimed that people end up wasting almost an entire day when they take a vacation.

This can happen while standing in a queue or searching for places to visit, people do not keep a count of the time they have actually utilised during the trip. As a result, they end up doing much lesser activities than they originally had planned.

According to a recent report in Fox News, the study has also shared the fact that people try to justify time waste with planning and scheduling activities whereas the truth is that these things can be done well ahead to save time during the trip.

The average time waste according to the study commissioned by Sykes Holiday Cottages also said the people taking a seven days' trip waste a minimum of 17-and-a-half hours to figure out various factors.

But there are other causes involved as well. When one visits any crowded location, the real-time spent to enjoy the location is lesser than the time spent on reaching and trying to get involved. For instance, if one visits an amusement park, the activities take lesser time than the preparatory and other phases.

New Zealand's research institute in Antarctica is scaling back the number of projects planned for the upcoming season, in an effort to keep the continent free of coronavirus, it was reported on Tuesday.

The government agency, Antarctica New Zealand, told the BBC on Tuesday that it was dropping 23 of the 36 research projects.

Only long-term science monitoring, essential operational activity and planned maintenance will go ahead.

The upcoming research season runs from October to March.

"As COVID-19 sweeps the planet, only one continent remains untouched and (we) are focused on keeping it that way," Antarctica New Zealand told the BBC.

The organisation's chief executive Sarah Williamson said the travel limits and a strict managed isolation plan were the key factors for keeping Scott Base - New Zealand's research facility - virus free.

"Antarctica New Zealand is committed to maintaining and enhancing the quality of New Zealand's Antarctic scientific research. However, current circumstances dictate that our ability to support science is extremely limited this season" she said.

Earlier in April, Australia announced that it would scale back its activity in the 2020-21 summer season.

This included decreasing operational capacity and delaying work on some major projects.