Institute of Astronomy

Astronomy News

Weird tiny galaxies found hiding in Hubble’s Ultra Deep Field

30 November 2017 - 9:41am

We just found 72 new galaxies in one of the most studied areas of the sky. We can’t see their stars, but they were revealed by the glow of hydrogen gas

Cuts likely for one of NASA’s next big space-based telescopes

30 November 2017 - 9:40am

NASA’s Wide Field Infrared Survey Telescope is crippled by rising costs. To get it off the ground, the agency may have to alter its scientific mission

Measurement of the multi-TeV neutrino interaction cross-section with IceCube using Earth absorption

30 November 2017 - 9:39am

Measurement of the multi-TeV neutrino interaction cross-section with IceCube using Earth absorption

Nature 551, 7682 (2017). doi:10.1038/nature24459

Authors:

Neutrinos interact only very weakly, so they are extremely penetrating. The theoretical neutrino–nucleon interaction cross-section, however, increases with increasing neutrino energy, and neutrinos with energies above 40 teraelectronvolts (TeV) are expected to be absorbed as they pass through the Earth. Experimentally, the cross-section has been determined only at the relatively low energies (below 0.4 TeV) that are available at neutrino beams from accelerators. Here we report a measurement of neutrino absorption by the Earth using a sample of 10,784 energetic upward-going neutrino-induced muons. The flux of high-energy neutrinos transiting long paths through the Earth is attenuated compared to a reference sample that follows shorter trajectories. Using a fit to the two-dimensional distribution of muon energy and zenith angle, we determine the neutrino–nucleon interaction cross-section for neutrino energies 6.3–980 TeV, more than an order of magnitude higher than previous measurements. The measured cross-section is about 1.3 times the prediction of the standard model, consistent with the expectations for charged- and neutral-current interactions. We do not observe a large increase in the cross-section with neutrino energy, in contrast with the predictions of some theoretical models, including those invoking more compact spatial dimensions or the production of leptoquarks. This cross-section measurement can be used to set limits on the existence of some hypothesized beyond-standard-model particles, including leptoquarks.

MUSE Probes Uncharted Depths of Hubble Ultra Deep Field

30 November 2017 - 9:36am
Astronomers using the MUSE instrument on ESO’s Very Large Telescope in Chile have conducted the deepest spectroscopic survey ever. They focused on the Hubble Ultra Deep Field, measuring distances and properties of 1600 very faint galaxies including 72 galaxies that have never been detected before, even by Hubble itself. This groundbreaking dataset has already resulted in 10 science papers that are being published in a special issue of Astronomy & Astrophysics. This wealth of new information is giving astronomers insight into star formation in the early Universe, and allows them to study the motions and other properties of early galaxies — made possible by MUSE’s unique spectroscopic capabilities.

Jocelyn Bell Burnell doesn't mind Nobel overlook

30 November 2017 - 9:34am

The astrophysicist says at the time students weren't awarded Nobel Prizes.

Stellar motions in nearby galaxy hint at underlying dark matter

29 November 2017 - 9:25am

By pinning down, for the first time, the three-dimensional motions of individual stars in the nearby Sculptor dwarf galaxy, astronomers have shed new light on the distribution of invisible dark matter that pervades the galaxy. This study combined the positions of stars measured by ESA's Gaia mission with observations from the NASA/ESA Hubble Space Telescope taken twelve years earlier.

Hubble and Gaia team up to measure 3D stellar motion with record-breaking precision [heic1719]

29 November 2017 - 9:24am

A team of astronomers used data from both the NASA/ESA Hubble Space Telescope and ESA's Gaia satellite to directly measure the 3D motions of individual stars in a nearby galaxy. The achieved accuracy is better than anything previously measured for a galaxy beyond the Milky Way. The motions provide a field test of the currently-accepted cosmological model and also measure the trajectory of the galaxy through space. The results are published in Nature Astronomy.

We’ve found a bunch of dwarf galaxies we thought didn’t exist

29 November 2017 - 9:22am

The missing dwarf galaxies around the Milky Way have been found. Their existence means dark matter could be made of particles that are warmer than we expected

Mysterious gamma rays in Crab nebula traced to pulsar winds

29 November 2017 - 9:22am

Ultra-bright flashes in the Crab nebula have baffled astronomers, but they could result from winds created by a pulsar at the heart of the gas cloud

A force to be reckoned with

29 November 2017 - 9:20am

Think you know what gravity is? Think again. New research is revealing how little we know about this most mysterious of forces. Read the rest of the article from the latest version of CAM, the University's alumni magazine, here.

Gravity is one of the universe's great mysteries. We decided to find out why.

La TigreSupermassive black holes


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How to solve the problem of space junk

29 November 2017 - 9:19am

A British spacecraft is trying to clean up what we send up but never bring down.

Einstein’s theory put to the test

27 November 2017 - 9:10am

Einstein’s theory put to the test

Einstein’s theory put to the test, Published online: 24 November 2017; doi:10.1038/d41586-017-07497-x

Attempts to break relativity get ever-more stringent.

Signs of running water on Mars dunes are probably just dry sand

23 November 2017 - 9:15am

The strange striped patterns that appear and fade away on Martian slopes were once thought to be evidence of flowing water – they’re actually made by dry sand

Light pollution is set to double between now and 2050

23 November 2017 - 9:14am

The first global “light census” shows that the area affected by artificial lighting is growing by 2.2 per cent every year, posing risks to wildlife and human health

Giant telescope’s mobile-phone ‘dead zones’ rile South African residents

23 November 2017 - 9:12am

Giant telescope’s mobile-phone ‘dead zones’ rile South African residents

Nature 551, 7681 (2017). http://www.nature.com/doifinder/10.1038/nature.2017.22998

Author: Sarah Wild

Sensitive radio dishes of the Square Kilometre Array will affect phone reception — and could harm local economies, say farmers.

Exoplanet hunters rethink search for alien life

23 November 2017 - 9:12am

Exoplanet hunters rethink search for alien life

Nature 551, 7681 (2017). http://www.nature.com/doifinder/10.1038/nature.2017.23023

Author: Alexandra Witze

Astronomers expand ideas of how chemistry and geology could affect chances for life on other worlds.

Light pollution: Night being lost in many countries

23 November 2017 - 9:11am

Much of the world is "losing the night" as artificial light becomes brighter and more widespread, say scientists.

High-energy 'ghost particles' absorbed by Earth

23 November 2017 - 9:10am

Neutrinos are famous for travelling through solid objects, but they don't go through everything, a study shows.

The message we’re sending to nearby aliens is no threat to Earth

22 November 2017 - 9:21am

Critics fear provoking hostile extraterrestrials by beaming messages to our closest exoplanets but there's no need to worry, says METI president Douglas Vakoch

We got a good look at the interstellar asteroid and it’s weird

22 November 2017 - 9:20am

Our first detailed glimpse at ‘Oumuamua, the interstellar asteroid that recently flew by Earth, shows it’s one of the weirdest asteroids we’ve ever seen