RSS chief pays tribute to Gauri Lankesh, Dharam Singh

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.

Bengaluru, May 28: A thousand government schools in Karnataka are set to get Englishmedium sections from this academic year (2020-21). These institutions will function in both English and Kannada medium.

The decision was taken by primary and secondary education minister S Suresh Kumar and officials of the education department at a meeting on Wednesday.

Suresh Kumar said dualmedium will help improve the standard of schools and enable their development. The poorest of the poor spend almost 40% of their income on their children’s education in private schools. With the introduction of dual-medium, the government hopes such families will be able to save their earnings, he said. These schools will impart lessons in both English and Kannada. They will also provide textbooks in both languages.

‘Kannada must for all’

The meeting reviewed implementation of the compulsory Kannada Language Learning Act, 2015. Officials from the Kannada Development Authority were present at the meeting who claimed that some private schools have failed to implement the Act properly.

“Action will be taken against such institutions. Every child studying in schools across the state must learn Kannada,” Kumar said at the meeting.

Mar 11: Thirteen of the 22 rebel MLAs in Madhya Pradesh have given an assurance that "they are not leaving the Congress", senior party leader Digvijaya Singh said on Thursday while expressing confidence that the Kamal Nath-led government in the state will win a floor test.

"We are not keeping quiet. We are not sleeping," Singh told PTI, a day after Congress leader from the state Jyotiraditya Scindia quit the Congress and 22 MLAs submitted their resignations from the assembly in Madhya Pradesh.

Scindia was offered the post of Madhya Pradesh deputy chief minister but wanted his nominee, Singh said. However, Kamal Nath refused to accept a "chela", he said.

Scindia, he said, could have been a Congress nominee to the Rajya Sabha but "only Modi-Shah" can give a Cabinet post to the "over-ambitious" leader.