Luminous galaxy reionizing surroundings 13 billion years ago

Agencies
July 2, 2020

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.

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Agencies
February 6,2020

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.

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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 15,2020

New Delhi, Jul 15: The employees union of state-run telecom operator BSNL will stage protests across the country on Thursday on a host of issues including the cancellation of its 4G tender and non-payment of salaries.

All major unions are organising ‘lunch-hour black-flag' demonstrations throughout the country under the banner of All Unions and Association of BSNL (AUAB), said a statement by AUAB. These demonstrations will be organised, by maintaining social distancing and by taking other precautions, like wearing of masks. The BSNL employees will also wear black-badges the whole day on July 16.

The employees body would demand that BSNL should immediately be allowed to roll out its 4G services and the tender should be issued immediately. Further, they want that in the matter of procuring new equipment and upgradation, there should not be any discrimination between BSNL and other private telecom service providers.

Recently, the Centre cancelled the 4G upgradation tender for BSNL as it had decided to come up with fresh specifications for the upgrade process, in a move to keep Chinese technology companies at bay as the border tussle escalated with the northern neighbour.

The Department of Telecommunications (DoT) would issue a fresh tender for the same, and people in the know said that Chinese companies may not be allowed to participate.

"The agitational programme is being organised to express the deep anguish and resentment of the employees against cancellation of BSNL's 4G tender, cancellation of BSNL's proposal for upgradation of its 49,300 BTSs to 4G, abnormal delay in issuing ‘Add on Order' for 4G equipments, inordinate delay in the implementation of BSNL's Revival Package and against the non-settlement of the burning problems of the employees," said the statement.

The umbrella body of BSNL's employees' unions noted that rolling out of 4G services is the backbone for the revival of this telecom PSU, but the recent cancellation of the tender floated by BSNL for procuring 4G equipment at a cost of Rs 9,300 crore, has brought the company back to square one.

It said that BSNL is already having 49,300 base transceiver stations (BTS), which are 4G compatible and through minor upgradation, all these equipment can be converted into 4G BTSs with an investment of about Rs 1,500 crore.

In addition to this, BSNL could have added another 15,000 BTSs, by placing an Add on Order to the existing mobile tender, it added.

Noting that in October 2019, the PSU could have rolled out pan-India 4G services, AUAB said: "Being the sole owner of the company, the Government of India also cannot shirk its responsibility in this matter."

"Adding insult to injury, the tender floated by BSNL to procure 4G equipment, has been cancelled by the government, based on a complaint from the Telecom Equipments and Services Promotional Council (TEPC)," it said.

AUAB said that BSNL is already lagging four years behind the private operators, in terms of 4G and the cancellation of the tender is going to inordinately delay the company's 4G launch.

Saying that TEPC's contention has been to bar foreign companies from participating in BSNL's tender, AUAB statement pointed out that when private operators are procuring equipment from multinationals, "why BSNL alone should be compelled to procure 4G equipments from domestic vendors, whose 4G technology is not tested or proven so far."

It alleged a conspiracy to destabilise BSNL by disrupting its rolling out of 4G services.

AUAB further said that even after the lapse of nine months, the implementation of the much publicised BSNL's Revival Package is moving at a snail's pace.

"Except the swift retrenchment of 79,000 BSNL employees under VRS, all other assurances given in BSNL's Revival Package have been put in cold storage."

The management should ensure that the salary payment of the employees is made on the last working day of every month. Deductions made from employees' salary, on account of "society dues", should immediately be remitted, it said.

Regarding the monetisation of the company's assets under the revival package, the organisation said that the land asset should not be handed over to corporates, at "throwaway" prices.

"These lands should be sold in a transparent manner and at the prevailing market rates. They should not be sold at book value or at circle rates. The AUAB will strictly monitor these dealings," it said.

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