Institute of Astronomy

Astronomy News

Hubble and Chandra Discover Dark Matter Is Not as Sticky as Once Thought

27 March 2015 - 10:16am

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In particle physics labs, like the Large Hadron Collider in Geneva, Switzerland, scientists smash atoms together to study the underpinnings of matter and energy. On the scale of the macrocosm, nature provides a similar experiment by crashing clusters of galaxies together. Besides galaxies and gas, the galaxy clusters contain huge amounts of dark matter. Dark matter is a transparent form of matter that makes up most of the mass in the universe. During collisions, the clouds of gas enveloping the galaxies crash into each other and slow down or stop. Astronomers found that the dark matter continued straight through the violent collisions, without slowing down relative to the galaxies. Their best explanation is that the dark matter did not interact with visible particles, and it also interacted less frequently with other dark matter than previously thought. Astronomers used the Hubble Space Telescope and Chandra X-ray Observatory to study 72 large galaxy cluster collisions. Chandra traced the hot gas, and Hubble saw how the invisible dark matter warps space and distorts the images of background stars. This allowed for the distribution of dark matter in the collision to be mapped. The finding narrows down the options for what this dark matter might be.

Best View Yet of Dusty Cloud Passing Galactic Centre Black Hole

27 March 2015 - 10:15am
The best observations so far of the dusty gas cloud G2 confirm that it made its closest approach to the supermassive black hole at the centre of the Milky Way in May 2014 and has survived the experience. The new result from ESO’s Very Large Telescope shows that the object appears not to have been significantly stretched and that it is very compact. It is most likely to be a young star with a massive core that is still accreting material. The black hole itself has not yet shown any increase in activity.

Dark matter even darker than once thought - Hubble explores the dark side of cosmic collisions [heic1506]

27 March 2015 - 10:14am

Astronomers using observations from the NASA/ESA Hubble Space Telescope and NASA's Chandra X-ray Observatory have studied how dark matter in clusters of galaxies behaves when the clusters collide. The results, published in the journal Science on 27 March 2015, show that dark matter interacts with itself even less than previously thought, and narrow down the options for what this mysterious substance might be.

NASA’s Hubble, Chandra Find Clues that May Help Identify Dark Matter

27 March 2015 - 10:13am

Using observations from NASA’s Hubble Space Telescope and Chandra X-ray Observatory, astronomers have found that dark matter does not slow down when colliding with itself, meaning it interacts with itself less than previously thought. Researchers say this finding narrows down the options for what this mysterious substance might be.

NASA Asteroid Hunter Spacecraft Data Available to Public

27 March 2015 - 10:13am

Millions of images of celestial objects, including asteroids, observed by NASA's Near-Earth Object Wide-field Survey Explorer (NEOWISE) spacecraft now are available online to the public. The data was collected following the restart of the asteroid-seeking spacecraft in December 2013 after a lengthy hibernation.

Black holes devour stars in gulps and nibbles

27 March 2015 - 10:12am

Black holes rip stars apart and feast on them when they approach too close – but some black holes are gluttons while others play with their food

Galaxy smash-ups show dark matter wants to be alone

27 March 2015 - 10:10am

Hints that dark matter might interact with itself via a new force are dashed

Dark matter flits through collisions

27 March 2015 - 10:00am

A long-running study shows dark matter coasts unscathed through galactic collisions, betraying a ghostly lack of interaction with the known Universe.

How black holes clear galaxies of star-making gas

26 March 2015 - 10:17am

Astronomers have found proof that the strong winds blown by a supermassive black hole are dispersing the gas reservoir of its host galaxy. The new finding relies on the observation of two related phenomena in the same galaxy: a large-scale galactic outflow, seen by ESA's Herschel space observatory, and a black-hole driven wind at the galaxy's core, detected with the Japanese/US Suzaku X-ray observatory. By showing how the black hole wind is in fact driving the gas outflow that affects the entire galaxy, the discovery demonstrates the key role played by black holes in regulating the formation of stars in their host galaxies.

Bright spots on Ceres could be active ice

26 March 2015 - 10:17am

Bright spots on Ceres could be active ice

Nature 519, 7544 (2015).

Author: Alexandra Witze

Early data from Dawn spacecraft bring scientists closer to clearing up mystery about dwarf planet.

Wind from the black-hole accretion disk driving a molecular outflow in an active galaxy

26 March 2015 - 10:16am

Wind from the black-hole accretion disk driving a molecular outflow in an active galaxy

Nature 519, 7544 (2015). doi:10.1038/nature14261

Authors: F. Tombesi, M. Meléndez, S. Veilleux, J. N. Reeves, E. González-Alfonso & C. S. Reynolds

Powerful winds driven by active galactic nuclei are often thought to affect the evolution of both supermassive black holes and their host galaxies, quenching star formation and explaining the close relationship between black holes and galaxies. Recent observations of large-scale molecular outflows in ultraluminous infrared galaxies support this quasar-feedback idea, because they directly trace the gas from which stars form. Theoretical models suggest that these outflows originate as energy-conserving flows driven by fast accretion-disk winds. Proposed connections between large-scale molecular outflows and accretion-disk activity in ultraluminous galaxies were incomplete because no accretion-disk wind had been detected. Conversely, studies of powerful accretion-disk winds have until now focused only on X-ray observations of local Seyfert galaxies and a few higher-redshift quasars. Here we report observations of a powerful accretion-disk wind with a mildly relativistic velocity (a quarter that of light) in the X-ray spectrum of IRAS F11119+3257, a nearby (redshift 0.189) optically classified type 1 ultraluminous infrared galaxy hosting a powerful molecular outflow. The active galactic nucleus is responsible for about 80 per cent of the emission, with a quasar-like luminosity of 1.5 × 1046 ergs per second. The energetics of these two types of wide-angle outflows is consistent with the energy-conserving mechanism that is the basis of the quasar feedback in active galactic nuclei that lack powerful radio jets (such jets are an alternative way to drive molecular outflows).

Galaxy formation: When the wind blows

26 March 2015 - 10:16am

Galaxy formation: When the wind blows

Nature 519, 7544 (2015). doi:10.1038/519423a

Authors: James E. Geach

Astronomical observations of a luminous galaxy that has a central, mass-accreting supermassive black hole reveal how such entities launch and propel gas through galaxies at high speeds. See Letter p.436

Planetary science: Rings proposed for orbiting rock

26 March 2015 - 10:13am

Planetary science: Rings proposed for orbiting rock

Nature 519, 7544 (2015). doi:10.1038/519393a

An asteroid-sized rock orbiting between Saturn and Uranus may have a system of rings.Amanda Bosh of the Massachusetts Institute of Technology in Cambridge and her team observed the minor planet 2060 Chiron passing in front of a star, using NASA's Infrared Telescope Facility on

Mars rover detects 'useful nitrogen'

26 March 2015 - 10:12am

The Curiosity rover makes a detection of nitrogen compounds which provide further evidence that ancient Mars would have been a habitable world.

Just one week left to submit a talk or poster abstract for NAM 2015! This is a...

25 March 2015 - 10:18am
Just one week left to submit a talk or poster abstract for NAM 2015!

This is a great opportunity to share your research with a wide range of researchers, at the UK's biggest professional astronomy conference.A wide range of scientific topics are included.

The deadline is 1 April.

National Astronomy Meeting 2015
National Astronomy Meeting 2015

Wrecking ball Jupiter paved way for Earth

25 March 2015 - 10:15am

Jupiter may have ploughed through the early solar system, driving some of the first planets to a fiery death in the sun – and cleared room for planets like Earth

Colliding Stars Explain Enigmatic Seventeenth Century Explosion

24 March 2015 - 8:58am
New observations made with APEX and other telescopes reveal that the star that European astronomers saw appear in the sky in 1670 was not a nova, but a much rarer, violent breed of stellar collision. It was spectacular enough to be easily seen with the naked eye during its first outburst, but the traces it left were so faint that very careful analysis using submillimetre telescopes was needed before the mystery could finally be unravelled more than 340 years later. The results appear online in the journal Nature on 23 March 2015.

The RAS and Institute of Physics back the UK bid for the HQ of the Square Kilome...

24 March 2015 - 8:56am
The RAS and Institute of Physics back the UK bid for the HQ of the Square Kilometre Array to be at Jodrell Bank

RAS and IOP back UK bid for HQ of world’s largest telescope
The Royal Astronomical Society (RAS) and the Institute of Physics (IOP) have responded to the decision of the Square Kilometre Array (SKA) Organisation to extend its selection process to decide on where to site the permanent headquarters of the array

Australia finds 'huge asteroid impact'

24 March 2015 - 8:46am

Scientists in central Australia discover what they say is a 400km-wide underground asteroid crater - the largest impact area ever found.

Awesome photos from Europe's biggest solar eclipse

23 March 2015 - 10:27am

Umbraphiles in the UK saw the biggest solar eclipse in 16 years, but the European Space Agency beat the clouds and got a spectacular view from space