Rare luminous nebula spotted 10 billion light years away poses cosmic puzzle

February 26, 2017

Feb 26: Astronomers have spotted an enormous, glowing blob of gas in the distant universe, with no obvious source of power for the light it is emitting. Called an “enormous Lyman-alpha nebula” (ELAN), it is the brightest and among the largest of these rare objects, only a handful of which have been observed, the researchers said.

lya-nebula

The newly discovered nebula was found at a distance of 10 billion light years in the middle of a region with an extraordinary concentration of galaxies. Researchers found this massive overdensity of early galaxies, called a “protocluster,” through a novel survey project led by Zheng Cai, Hubble postdoctoral fellow at University of California, Santa Cruz in the US.

“Our survey was not trying to find nebulae. We"re looking for the most overdense environments in the early universe, the big cities where there are lots of galaxies,” said Cai, who is first author of a paper on the discovery to be published in the Astrophysical Journal.

“We found this enormous nebula in the middle of the protocluster, near the peak density,” Cai said. ELANs are huge blobs of gas surrounding and extending between galaxies in the intergalactic medium. They are thought to be parts of the network of filaments connecting galaxies in a vast cosmic web.

Previously discovered ELANs are likely illuminated by the intense radiation from quasars, but it is not clear what is causing the hydrogen gas in the newly discovered nebula to emit Lyman-alpha radiation (a characteristic wavelength of light absorbed and emitted by hydrogen atoms), the researchers said.

The newly discovered ELAN is known as MAMMOTH-1. “It"s a terrifically energetic phenomenon without an obvious power source,” said study co-author J. Xavier Prochaska, Professor at University of California, Santa Cruz.

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Agencies
July 18,2020

New Delhi, Jul 18: India's national cybersecurity agency CERT-in, has warned people of credit card skimming spreading across the world through e-commerce platforms.

Attackers are typically targeting e-commerce sites because of their wide presence, popularity and the environment LAMP (Linux, Apache, MySQL, and PHP), the Computer Emergency Response Team (CERT-In) said in a notice on Thursday.

Recently, attackers targeted sites which were hosted on Microsoft's IIS server running with the ASP.NET web application framework, it said.

Some of the sites affected by the attack were found to be running ASP.NET version 4.0.30319, which is no longer officially supported by Microsoft and may contain multiple vulnerabilities, CERT-In said.

The notice also included a list of best practices for website developers including the use of the latest version of ASP.NET web framework, IIS web server and database server.

The advisory is based on research by Malwarebytes which found that this skimming campaign likely began sometime in April this year.

Credit card skimming has become a popular activity for cybercriminals over the past few years, and the increase in online shopping during the pandemic means additional business for them, too, Malwarebytes said in a blog post, adding that attackers do not need to limit themselves to the most popular e-commerce platforms.

Researchers from global cybersecurity and anti-virus brand Kaspersky had warned in December last year that more cybercriminal groups will target online payment processing systems in 2020. 

It said that over the past couple of years, so-called JS-skimming (the method of stealing of payment card data from online stores), has gained immense popularity among attackers. 

Kaspersky researchers in their report said they are currently aware of at least 10 different actors involved in these type of attacks.

Their number will continue to grow during the next year, the report said, adding that the most dangerous attacks will be on companies that provide services such as e-commerce as-a-service, which will lead to the compromise of thousands of companies.

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Agencies
July 4,2020

The Mars Colour Camera (MCC) onboard ISRO's Mars Orbiter Mission has captured the image of Phobos, the closest and biggest moon of Mars.

The image was taken on July 1 when MOM was about 7,200 km from Mars and 4,200 km from Phobos.

"Spatial resolution of the image is 210 m.

This is a composite image generated from 6 MCC frames and has been color corrected," ISRO said in an update along with the image.

Phobos is largely believed to be made up of carbonaceous chondrites.

According to ISRO, "the violent phase that Phobos has encountered is seen in the large section gouged out from a past collision (Stickney crater) and bouncing ejecta."

"Stickney, the largest crater on Phobos along with the other craters (Shklovsky, Roche & Grildrig) are also seen in this image," it said.

The mission also known as Mangalyaan was initially meant to last six months, but subsequently ISRO had said it had enough fuel for it to last "many years."

The country had on September 24, 2014 successfully placed the Mars Orbiter Mission spacecraft in orbit around the red planet, in its very first attempt, thus breaking into an elite club.

ISRO had launched the spacecraft on its nine-month- long odyssey on a homegrown PSLV rocket from Sriharikota in Andhra Pradesh on November 5, 2013.

It had escaped the earth's gravitational field on December 1, 2013.

The Rs 450-crore MOM mission aims at studying the Martian surface and mineral composition as well as scan its atmosphere for methane (an indicator of life on Mars).

The Mars Orbiter has five scientific instruments - Lyman Alpha Photometer (LAP), Methane Sensor for Mars (MSM), Mars Exospheric Neutral Composition Analyser (MENCA), Mars Colour Camera (MCC) and Thermal Infrared Imaging Spectrometer

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Agencies
June 19,2020

Denser places, assumed by many to be more conducive to the spread of the coronavirus that causes COVID-19, are not linked to higher infection rates, say researchers.

The study, led by Johns Hopkins University, published in the Journal of the American Planning Association, also found that dense areas were associated with lower COVID-19 death rates.

"These findings suggest that urban planners should continue to practice and advocate for compact places rather than sprawling ones, due to the myriad well-established benefits of the former, including health benefits," says study lead author Shima Hamidi from Johns Hopkins Bloomberg School of Public Health in the US.

For their analysis, the researchers examined SARS-CoV-2 infection rates and COVID-19 death rates in 913 metropolitan counties in the US.

When other factors such as race and education were taken into account, the authors found that county density was not significantly associated with county infection rate.

The findings also showed that denser counties, as compared to more sprawling ones, tended to have lower death rates--possibly because they enjoyed a higher level of development including better health care systems.

On the other hand, the research found that higher coronavirus infection and COVID-19 mortality rates in counties are more related to the larger context of metropolitan size in which counties are located.

Large metropolitan areas with a higher number of counties tightly linked together through economic, social, and commuting relationships are the most vulnerable to the pandemic outbreaks.

According to the researchers, recent polls suggest that many US citizens now consider an exodus from big cities likely, possibly due to the belief that more density equals more infection risk.

Some government officials have posited that urban density is linked to the transmissibility of the virus.

"The fact that density is unrelated to confirmed virus infection rates and inversely related to confirmed COVID-19 death rates is important, unexpected, and profound," said Hamidi.

"It counters a narrative that, absent data and analysis, would challenge the foundation of modern cities and could lead to a population shift from urban centres to suburban and exurban areas," Hamidi added.

The analysis found that after controlling for factors such as metropolitan size, education, race, and age, doubling the activity density was associated with an 11.3 per cent lower death rate.

The authors said that this is possibly due to faster and more widespread adoption of social distancing practices and better quality of health care in areas of denser population.

The researchers concluded that a higher county population, a higher proportion of people age 60 and up, a lower proportion of college-educated people, and a higher proportion of African Americans were all associated with a greater infection rate and mortality rate.

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