India's test created 400 pieces of debris, risk to Space Station: NASA

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, Feb 5: Experts warned a US government panel last night that India's Muslims face risks of expulsion and persecution under the country’s new Citizenship Amendment Act (CAA) which has triggered major protests.

The hearing held inside Congress was called by the US Commission on International Freedom, which has been denounced by the Indian government as biased.

Ashutosh Varshney, a prominent scholar of sectarian violence in India, told the panel that the law championed by prime minister Narendra Modi's government amounted to a move to narrow the democracy's historically inclusive and secular definition of citizenship.

"The threat is serious, and the implications quite horrendous," said Varshney, a professor at Brown University.

"Something deeply injurious to the Muslim minority can happen once their citizenship rights are taken away," he said.

Varshney warned that the law could ultimately lead to expulsion or detention -- but, even if not, contributes to marginalization.

"It creates an enabling atmosphere for violence once you say that a particular community is not fully Indian or its Indianness in grave doubt," he said.

India's parliament in December passed a law that fast-tracks citizenship for persecuted non-Muslim minorities from neighboring countries.

Responding to criticism at the time from the US commission, which advises but does not set policy, India's External Affairs Ministry said the law does not strip anyone's citizenship and "should be welcomed, not criticized, by those who are genuinely committed to religious freedom."

Fears are particularly acute in Assam, where a citizens' register finalized last year left 1.9 million people, many of them Muslims, facing possible statelessness.

Aman Wadud, a human rights lawyer from Assam who traveled to Washington for the hearing, said that many Indians lacked birth certificates or other documentation to prove citizenship and were only seeking "a dignified life."

The hearing did not exclusively focus on India, with commissioners and witnesses voicing grave concern over Myanmar's refusal to grant citizenship to the Rohingya, the mostly Muslim minority that has faced widespread violence.

Gayle Manchin, the vice chair of the commission, also voiced concern over Bahrain's stripping of citizenship from activists of the Shiite majority as well as a new digital ID system in Kenya that she said risks excluding minorities.

More than 40 people were killed last week in New Delhi in sectarian violence sparked by the citizenship law.

India on Tuesday lodged another protest after the UN human rights chief, Michele Bachelet, sought to join a lawsuit in India that challenges the citizenship law's constitutionality.

Dubai, Jan 8: A Ukrainian airliner crashed soon after taking off from Tehran's Imam Khomeini airport on Wednesday, killing all 176 people aboard, Iran's state television and Ukraine's leaders said.

The Boeing 737 belonging to Ukraine International Airlines crashed near the airport and burst into flames. Ukraine's embassy in Iran, citing preliminary information, said the plane had suffered engine failure and the crash was not caused by "terrorism".

Ukraine President Volodymyr Zelenskiy said there were no survivors.

"My sincere condolences to the relatives and friends of all passengers and crew," Zelenskiy said in a statement, adding that Ukraine was seeking to establish the circumstances of the crash and the death toll.

Iranian TV said the crash was due to technical problems but did not elaborate. State broadcaster IRIB said on its website that one of the plane's two black boxes - the flight data recorder and the cockpit voice recorder - had been found.

Iranian media quoted an Iranian aviation official as saying the pilot of the airliner did not declare an emergency.

There was no official word from Ukraine International Airlines. It was the Kiev-based airline's first fatal crash.

"The fire is so heavy that we cannot (do) any rescue... we have 22 ambulances, four bus ambulances and a helicopter at the site," Pirhossein Koulivand, head of Iran's emergency services, told Iranian state television.

Ukraine's prime minister and Iranian state TV said 167 passengers and 9 crew were on board. Iranian TV said 32 of those on board were foreigners.

Television footage showed debris and smouldering engine parts strewn across a field, and rescue workers with face masks retrieving bodies of the victims.

According to air tracking service FlightRadar24, the plane that crashed was Flight PS 752 and was flying to Kiev. The plane was three years old and was a Boeing 737-800NG, it said.

The model's twin engines are made by CFM International, a U.S.-French venture co-owned by General Electric and France's Safran.

Modern aircraft are designed and certified to cope with an engine failure shortly after take-off and to fly for extended periods on one engine. However, an uncontained engine failure releasing shrapnel can cause damage to other aircraft systems.

A spokesman for Boeing said the company was aware of media reports of a plane crash in Iran and was gathering more information. The plane manufacturer grounded its 737 MAX fleet in March after two crashes that killed 346 people.

The 737-800 is one of the world's most-flown models with a good safety record and which does not have the software feature implicated in crashes of the 737 MAX.

Under international rules overseen by the United Nations, Iran is responsible for leading the crash investigation.

Ukraine would be involved and the United States would usually be accredited as the country where the Boeing jet was designed and built. France, where the engine maker CFM has half its activities, may also be involved.

There was no immediate word on whether the U.S. National Transportation Safety Board would be involved in the probe amid escalating tensions between the U.S. and Iran. The NTSB usually invites Boeing to give technical advice in such investigations.