This monsoon head to Munnar to witness 'Neelakurinji flower'

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.

Facebook will introduce a new notification screen on its platform that will warn users if the article they are about to share is over 90 days old, the company announced on Thursday.

“We’re starting to globally roll out a notification screen that will let people know when news articles they are about to share are more than 90 days old,” Facebook wrote in a blog post.

The social media platform had previously introduced a context button in 2018 that provides information about the sources of articles in the News Feed. Building upon that, the new feature will inform users about the timeliness of the article.

“To ensure people have the context they need to make informed decisions about what to share on Facebook, the notification screen will appear when people click the share button on articles older than 90 days, but will allow people to continue sharing if they decide an article is still relevant,” Facebook said.

The social media giant stated that timeliness is important in understanding the context of an article and curbing the spread of misinformation on the platform.

“News publishers, in particular, have expressed concerns about older stories being shared on social media as current news, which can misconstrue the state of current events. Some news publishers have already taken steps to address this on their own websites by prominently labelling older articles to prevent outdated news from being used in misleading ways,” Facebook added.

Apart from this, the platform will also be testing a similar notification screen for information related to the global Covid-19 pandemic. The notification screen will provide information about the source of the link shared in a post if the link is related to information on Covid-19. It will also direct people to its previously introduced Covid-19 information centre for “authoritative” health information, it said.

Cybercriminals continue to exploit public fear of rising coronavirus cases through malware and phishing emails in the guise of content coming from the Centers for Disease Control and Prevention (CDC) in the US and World Health Organisation (WHO), says cybersecurity firm Kaspersky.

In the APAC region, Kaspersky has detected 93 coronavirus-related malware in Bangladesh, 53 in the Philippines, 40 in China, 23 in Vietnam, 22 in India and 20 in Malaysia. 

Single-digit detections were monitored in Singapore, Japan, Indonesia, Hong Kong, Myanmar, and Thailand. 

Along with the consistent increase of 2019 coronavirus cases comes the incessant techniques cybercriminals are using to prey on public panic amidst the global epidemic, the company said in a statement. 

Kaspersky also detected emails offering products such as masks, and then the topic became more commonly used in Nigerian spam emails. Researchers also found scam emails with phishing links and malicious attachments.

One of the latest spam campaigns mimics the World Health Organisation (WHO), showing how cybercriminals recognise and are capitalising on the important role WHO has in providing trustworthy information about the coronavirus.

"We would encourage companies to be particularly vigilant at this time, and ensure employees who are working at home exercise caution. 

"Businesses should communicate clearly with workers to ensure they are aware of the risks, and do everything they can to secure remote access for those self-isolating or working from home," commented David Emm, principal security researcher.

Some malicious files are spread via email. 

For example, an Excel file distributed via email under the guise of a list of coronavirus victims allegedly sent from the World Health Organisation (WHO) was, in fact, a Trojan-Downloader, which secretly downloads and installs another malicious file. 

This second file was a Trojan-Spy designed to gather various data, including passwords, from the infected device and send it to the attacker.