A group of astronomers has been able to follow stardust being made in real time — during the aftermath of a supernova explosion. For the first time they show that these cosmic dust factories make their grains in a two-stage process, starting soon after the explosion, but continuing for years afterwards. The team used ESO’s Very Large Telescope (VLT) in northern Chile to analyze the light from the supernova SN 2010jl as it slowly faded. The new results are published online in the journal Nature on 9 July 2014.
The origin of cosmic dust in galaxies is still a mystery . Astronomers know that supernovae may be the primary source of dust, especially in the early universe, but it is still unclear how and where dust grains condense and grow. It is also unclear how they avoid destruction in the harsh environment of a star-forming galaxy. But now, observations using ESO’s VLT at the Paranal Observatory in northern Chile are lifting the veil for the first time. Continue reading Vlt Clears up dusty mystery: New Observations reveal how Stardust forms around a Supernova→
The bright core of a spiral galaxy has unexpectedly dimmed, according to a new study by an international team of astronomers. The nucleus of galaxy NGC 5548, which contains a region of powerful X-ray light surrounding the galaxy’s central black hole, has been obscured by a fast-flowing stream of gas. Such behavior, which is rarely seen in the heart of this type of galaxy, casts new light on the poorly understood processes governing the interaction between galaxies and their central black holes. Continue reading Fast-Flowing Gas Curtails Galaxy’s Glow→
They may only be little, but they pack a star-forming punch: new observations from the NASA/ESA Hubble Space Telescope show that starbursts in dwarf galaxies played a bigger role than expected in the early history of the Universe.
Australian astronomers have discovered what makes some spiral galaxies fat and bulging while others are flat discs — and it’s all about how fast they spin.
The Astrophysical Journal
The research, led by the International Centre for Radio Astronomy Research (ICRAR) in Perth, found that fast-rotating spiral galaxies are flat and thin while equally sized galaxies that rotate slowly are fatter.
The study was published today in the prestigious Astrophysical Journal and was part of “The Evolving Universe” research theme of the ARC Center of Excellence for All-sky Astrophysics (CAASTRO).
ICRAR Research Associate Professor Danail Obreschkow, from The University of Western Australia, said it is a much-debated mystery why galaxies look so different to each other.
“Some galaxies are very flat discs of stars and others are more bulging or even spherical,” he said.
The Andromeda Galaxy is surrounded by a swarm of small satellite galaxies. Researchers from the Niels Bohr Institute, among others, have detected a stream of stars in one of the Andromeda Galaxy’s outer satellite galaxies, a dwarf galaxy called Andromeda II. The movement of the stars tells us that what we are observing is the remnant of a merger between two dwarf galaxies. Mergers between galaxies of such low mass has not been observed before. The results are published in the scientific journal Nature.
The galaxies in the early universe started off small and the theory of the astronomers is that the baby galaxies gradually grew larger and more massive by constantly colliding with neighboring galaxies to form new, larger galaxies. Large, massive galaxies constantly attract smaller galaxies due to gravity and they eventually merge together and grow even larger.