India chose much lower for A-SAT test to avoid debris threat to global space assets: DRDO

Agencies
April 6, 2019

New Delhi, Apr 6: India chose a much lower orbit of less than 300 km during Mission Shakti for "capability demonstration" and to avoid threat of debris to global space assets, DRDO Chairman G Satheesh Reddy said Saturday.

His remark comes days after NASA raised concerns about the spread of debris from the Anti-Satellite Test (A-SAT) test India conducted on March 27.

Reddy, at a briefing held at the DRDO Bhawan here, said the interceptor had the capability to intercept satellites in orbit of 1,000 km.

"An orbit of around 300 km was chosen for the test for capability demonstration, and the purpose was to avoid threat of debris to any global space assets," Reddy said.

"The debris created following the intercept will decay in a matter of weeks," he added.

On Tuesday, the NASA had termed a "terrible thing" India's shooting down of one its satellites, saying the hit-to-kill mission created about 400 pieces of orbital debris.

India's Ministry of External Affairs too has said the test was done in the lower atmosphere to ensure that there is no space debris.

Prime Minister Narendra Modi has hailed the A-SAT test's success as "an unprecedented achievement" that makes India "a space power.

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News Network
June 30,2020

Bengaluru, Jun 30: Karnataka Chief Minister BS Yediyurappa on Monday launched 'Skill Connect Forum' and said that the government is committed to provide impetuous to creating jobs by reviving economic and industrial activities.

The 'Skill Connect Forum' portal connects both private entrepreneurs and job seekers on the same platform.

After launching the forum, the Chief Minister said that the portal provides information on jobs available and who needs a job. "Under this forum, an unemployed will be imparted skills and then enabled to get a job," Yediyurappa said.
Besides providing jobs via registration, the portal also provides a skilled pool of people for those looking to hire, he added.

Deputy Chief Minister Dr CN Ashwath Narayan, who is also the Skill Development Minister said that portal will be a boon to the youth seeking jobs and it will avoid unemployment issue to a great extent.

"All these years, there was no information and communication between job seekers and recruiters. The portal will solve that problem," he said.

Narayan said that there was no proper information on skilled workers and job market. Moreover, skill development was not in sync with the market. All these issues have been addressed by the portal, he added.

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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 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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