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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.

As millions of people get hooked to online dating platforms, their proliferation has led to online romance scams becoming a modern form of fraud that have spread in several societies along with the development of social media like Facebook Dating, warn researchers.

For example, extra-marital dating app Gleeden has crossed 10 lakh users in India in COVID-19 times while dating apps like Tinder and Bumble have gained immense popularity.

According to researchers from University of Siena and Scotte University Hospital led by Dr Andrea Pozza, via a fictitious Internet profile, the scammer develops a romantic relationship with the victim for 6-8 months, building a deep emotional bond to extort economic resources in a manipulative dynamic.

"There are two notable features: on the one hand, the double trauma of losing money and a relationship, on the other, the victim's shame upon discovery of the scam, an aspect that might lead to underestimation of the number of cases," the authors wrote in a paper published in the journal Clinical Practice & Epidemiology in Mental Health.

Around 1,400 dating sites/chats have been created over the last decade in North America alone. In the UK, 23 per cent of Internet users have met someone online with whom they had a romantic relationship for a certain period and even 6 per cent of married couples met through the web.

"The online dating industry has given rise to new forms of pathologies and crime, said the authors.

The results showed that 63 per cent of social media users and 3 per cent of the general population reported having been a victim at least once.

Women, middle-aged people, and individuals with higher tendencies to anxiety, romantic idealization of affective relations, impulsiveness and susceptibility to relational addiction are at higher risk of being victims of the scam.

Online romance scams are, in other words, relationships constructed through websites for the purpose of deceiving unsuspecting victims in order to extort money from them.

The scammer always acts empathetically and attempts to create the impression in the victim that the two are perfectly synced in their shared view of life.

"The declarations of the scammer become increasingly affectionate and according to some authors, a declaration of love is made within two weeks from initial contact," the study elaborated.

After this hookup phase, the scammer starts talking about the possibility of actually meeting up, which will be postponed several times due to apparently urgent problems or desperate situations such as accidents, deaths, surgeries or sudden hospitalizations for which the unwitting victim will be manipulated into sending money to cover the momentary emergency.

Using the strategy of "testing-the-water", the scammer asks the victim for small gifts, usually to ensure the continuance of the relationship, such as a webcam, which, if successful, leads to increasingly expensive gifts up to large sums of money.

When the money arrives from the victim, the scammer proposes a new encounter.

The request for money can also be made to cover the travel costs involved in the illusory meeting. In this phase, the victim may start having second thoughts or showing doubt about the intentions of the partner and gradually decide to break off the relationship.

"In other cases, the fraudulent relationship continues or even reinforces itself as the victim, under the influence of ambivalent emotions of ardor and fear of abandonment and deception, denies or rationalizes doubts to manage their feelings," said the study.

In some cases, the scammer may ask the victim to send intimate body photos that will be used as a sort of implicit blackmail to further bind the victim to the scammer.

Once the scam is discovered, the emotional reaction of the victim may go through various phases: feelings of shock, anger or shame, the perception of having been emotionally violated (a kind of emotional rape), loss of trust in people, a sensation of disgust towards oneself or the perpetrator of the crime and a feeling of mourning.

"Understanding the psychological characteristics of victims and scammers will allow at-risk personality profiles to be identified and prevention strategies to be developed," the authors suggested.

Washington D.C., Feb 6: An international team of astronomers has found an unusual monster galaxy that existed about 12 billion years ago when the universe was only 1.8 billion years old.

The team of astronomers was led by scientists at the University of California, Riverside.

Dubbed XMM-2599, the galaxy formed stars at a high rate and then died. Why it suddenly stopped forming stars is unclear.

"Even before the universe was 2 billion years old, XMM-2599 had already formed a mass of more than 300 billion suns, making it an ultra massive galaxy," said Benjamin Forrest, a postdoctoral researcher in the UC Riverside Department of Physics and Astronomy and the study's lead author.

"More remarkably, we show that XMM-2599 formed most of its stars in a huge frenzy when the universe was less than 1 billion years old and then became inactive by the time the universe was only 1.8 billion years old," Forrest added.

The team used spectroscopic observations from the W. M. Keck Observatory's powerful Multi-Object Spectrograph for Infrared Exploration or MOSFIRE, to make detailed measurements of XMM-2599 and precisely quantify its distance.

The study results appear in the Astrophysical Journal.

"In this epoch, very few galaxies have stopped forming stars, and none are as massive as XMM-2599," said Gillian Wilson, a professor of physics and astronomy at UCR in whose lab Forrest works.

"The mere existence of ultramassive galaxies like XMM-2599 proves quite a challenge to numerical models. Even though such massive galaxies are incredibly rare at this epoch, the models do predict them."

"The predicted galaxies, however, are expected to be actively forming stars. What makes XMM-2599 so interesting, unusual, and surprising is that it is no longer forming stars, perhaps because it stopped getting fuel or its black hole began to turn on. Our results call for changes in how models turn off star formation in early galaxies," the professor stated.

The research team found XMM-2599 formed more than 1,000 solar masses a year in stars at its peak of activity -- an extremely high rate of star formation. In contrast, the Milky Way forms about one new star a year.

"XMM-2599 may be a descendant of a population of highly star-forming dusty galaxies in the very early universe that new infrared telescopes have recently discovered," said Danilo Marchesini, an associate professor of astronomy at Tufts University and a co-author on the study.

"We have caught XMM-2599 in its inactive phase," Wilson said, who led the W. M. Keck Observatory data acquisition
Co-author Michael Cooper, a professor of astronomy at UC Irvine, said this outcome is a strong possibility.

"Perhaps during the following 11.7 billion years of cosmic history, XMM-2599 will become the central member of one of the brightest and most massive clusters of galaxies in the local universe," he said.

"Alternatively, it could continue to exist in isolation. Or we could have a scenario that lies between these two outcomes," he stated.

The study was supported by grants from the National Science Foundation and NASA.