LAMOST tagged posts

An international team of astronomers has unveiled the nature of hundreds of gamma-ray emitting sources, discovering that most of them belong to the class of active galaxies known as blazars.

Their recent study was published in The Astronomical Journal.

One of the most intriguing challenges in modern gamma-ray astronomy is searching for low-energy counterparts of unidentified gamma-ray sources. Unidentified sources constitute about 1/3 of all celestial objects detected by the Fermi satellite to date, the most recent gamma-ray mission with unprecedented capabilities for observing the high energy sky.

Since the largest population of known gamma-ray sources are blazars, astronomers believe they can a...

The coloured region is the previously known Galactic disk. The present work has extended its limits much farther away: there is a probability 99.7 percent or 95.4 percent respectively that there are disk stars in the regions outside the dashed/dotted circles. Yellow dot is the position of the Sun. Background Milky Way image from ‘A Roadmap to the Milky Way’. Credit: R. Hurt, SSC-Caltech, NASA/JPL-Caltech

A team of researchers suggests that if we could travel at the speed of light it would take us 200,000 years to cross the disc of our Galaxy. Spiral galaxies such as the Milky Way have discs which are really thin, in which the major fraction of their stars are found. These discs are limited in size, so that beyond certain radius there are very few stars left.

In our Galaxy we were not aware...

The Sun. Elements of this image furnished by NASA. The Sun is capable of producing monstrous eruptions that can break down radio communication and power supplies here on Earth. The largest observed eruption took place in September 1859, where gigantic amounts of hot plasma from our neighboring star struck the Earth. Credit: © Vadimsadovski / Fotolia

Every now and then large sun storms strike the Earth where they cause aurora and in rare cases power cuts. These events are, however, nothing compared to the apocalyptic destruction we would experience if the Earth is struck by a superflare. An international research team has now shown that this is a scenario we may have to consider a real possibility.

Superflares have been a mystery since the Kepler mission discovered them in larger numbers 4...