Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Faint 'satellite galaxy' discovered

A faint “satellite galaxy” 10 billion light years from Earth is the lowest-mass object ever detected at such a distance, says University of California, Davis, physics professor Chris Fassnacht, who aided in the satellite’s discovery.
The find, described in a paper published online today (Jan. 18) in the journal Nature, could help astronomers find similar objects and confirm or reject theories about the structure of the cosmos.

Theory predicts that galaxies should be surrounded by halos of smaller, satellite blobs of mass, according to Fassnacht. Astronomers have detected such satellites around our own galaxy, the Milky Way, and nearby.

But they had not previously detected the predicted satellites of more distant galaxies.

Because most of the mass of galaxies is made up, not of stars, but of “dark matter,” which does not absorb or emit light, these distant objects may be very faint or even completely dark.

The team looked for faint or dark satellites of distant galaxies using a method called gravitational lensing. Using the Keck II telescope at the W.M. Keck Observatory on Mauna Kea, Hawaii, with “adaptive optics,” they found two galaxies aligned with each other, as viewed from Earth.

The nearer object’s gravitational field deflects the light from the more distant object as the light passes through or near the other object’s gravitational field, creating a distorted image as if passed through a lens. By analyzing these distorted images, the researchers could determine if there were any satellite galaxies clustered around the “lens” galaxy.

Adaptive optics make constant, tiny adjustments to the telescope mirror to compensate for the effects of the Earth’s atmosphere. As a result, the Keck telescopes can achieve higher resolution than the Hubble Space Telescope.

The technique can now be applied to many more galaxies, Fassnacht said. “As we collect more objects, we can do more precise tests of our simulations and make predictions about the structure of the universe,” he said.

First author Simona Vegetti, a postdoctoral researcher at the Massachusetts Institute of Technology, said: “Now we have one dark satellite, but suppose that we don’t find enough of them — then we will have to change the properties of dark matter.

“Or, we might find as many satellites as we see in the simulations, and that will tell us that dark matter has the properties we think it has.”

Fassnacht and Vegetti worked with Leon Koopmans of the University of Groningen, Netherlands; David Lagattuta, now at the Swinburne University of Technology, Australia; Matthew Auger, UC Santa Barbara; and John McKean of the Netherlands Foundation for Research in Astronomy. Lagattuta and Auger are former graduate students in Fassnacht’s lab, and McKean was a postdoctoral researcher at UC Davis.

The National Science Foundation funded the research.
About UC Davis

For more than 100 years, UC Davis has engaged in teaching, research and public service that matter to California and transform the world. Located close to the state capital, UC Davis has more than 32,000 students, more than 2,500 faculty and more than 21,000 staff, an annual research budget that exceeds $684 million, a comprehensive health system and 13 specialized research centers. The university offers interdisciplinary graduate study and more than 100 undergraduate majors in four colleges — Agricultural and Environmental Sciences, Biological Sciences, Engineering, and Letters and Science. It also houses six professional schools — Education, Law, Management, Medicine, Veterinary Medicine and the Betty Irene Moore School of Nursing.
Media contact(s):
Chris Fassnacht, Physics, (530) 554-2600,
Andy Fell, UC Davis News Service, (530) 752-4533,

Andy Fell | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht First results of NSTX-U research operations
26.10.2016 | DOE/Princeton Plasma Physics Laboratory

nachricht Scientists discover particles similar to Majorana fermions
25.10.2016 | Chinese Academy of Sciences Headquarters

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

'Neighbor maps' reveal the genome's 3-D shape

27.10.2016 | Life Sciences

Gene therapy shows promise for treating Niemann-Pick disease type C1

27.10.2016 | Life Sciences

Solid progress in carbon capture

27.10.2016 | Power and Electrical Engineering

More VideoLinks >>>