Category Astronomy/Space

This artist’s conception shows a blazar — the core of an active galaxy powered by a supermassive black hole. The VERITAS array has detected gamma rays from a blazar known as PKS 1441+25. Researchers found that the source of the gamma rays was within the relativistic jet but surprisingly far from the galaxy’s black hole. The emitting region is at least a tenth of a light-year away, and most likely is 5 light-years away. Credit: M. Weiss/CfA

In April 2015, after traveling for about half the age of the universe, a flood of powerful gamma rays from a distant galaxy slammed into Earth’s atmosphere. That torrent generated a cascade of light – a shower that fell onto the waiting mirrors of the Very Energetic Radiation Imaging Telescope Array System (VERITAS) in Arizona...

X-ray image of the XXL-South Field. Credit: ESA/XMM-Newton/XXL survey consortium/(S. Snowden, L. Faccioli, F. Pacaud)

ESO telescopes have provided an international team with the gift of the third dimension in a plus-sized hunt for the largest gravitationally bound structures in the Universe — galaxy clusters. Observations by the VLT and the NTT complement those from other observatories across the globe and in space as part of the XXL survey — one of the largest ever such quests for clusters.

Galaxy clusters are massive congregations of galaxies that host huge reservoirs of hot gas – the temperatures are so high that X-rays are produced...

Ritchey Crater, located near the Martian equator, has impact melt deposits containing clay minerals. Impact melt forms when rock melted during an impact cools and hardens. The clay minerals found within these deposits are very likely to have formed after the impact event. Most clay minerals on Mars are thought to have formed during the earliest Martian epoch, known as the Noachian. However, evidence from Ritchey crater and other post-Noachian craters, suggests that clay formation after the Noachian was not uncommon. Credit: NASA/JPL/University of Arizona/Brown University

Clays and other minerals formed when rocks are altered by water have been found in multiple locations on Mars. It’s been assumed that these minerals probably formed in the earliest Martian epoch, >3.7B yrs ago...

Regular spiral galaxies, such as the ‘whirlpool galaxy’ on the left, form far fewer stars than the clumpy galaxy on the right. The blue regions have the least star-forming gas and red-yellow regions have the most. Credit: Dr Danail Obreschkow, ICRAR. Image uses data from the Hubble Space Telescope.

Australian researchers have discovered why some galaxies are “clumpy” rather than spiral in shape – and it appears low spin is to blame. The finding challenges an earlier theory that high levels of gas cause clumpy galaxies and sheds light on the conditions that brought about the birth of most of the stars in the Universe.

Dr Danail Obreschkow from ICRAR, said 10B years ago the Universe was full of clumpy galaxies but these developed into more regular objects as they evolved...