Astronomers at the California Institute of Technology (Caltech) and their colleagues have provided unique insight into the nature of a young star-forming galaxy as it appeared only two billion years after the Big Bang and determined how the galaxy may eventually evolve to become a system like our own Milky Way.
The researchers found that the distant galaxy, which is typical in many respects to others at that epoch, shows clear signs of orderly rotation. The finding, in association with observations conducted at millimeter wavelengths, which are sensitive to cold molecular gas (an indicator of galactic rotation), suggests that the source is in the early stages of assembling a spiral disk with a central nucleus similar to those seen in spiral galaxies at the present day.
Using the Hubble Space Telescope, the team located a distinctive galaxy dubbed the "Cosmic Eye" because its form is distorted into a ring-shaped structure by the gravitational field of a foreground galaxy.
"Gravity has effectively provided us with an additional zoom lens, enabling us to study this distant galaxy on scales approaching only a few hundred light-years. This is 10 times finer sampling than hitherto possible," explains postdoctoral research scholar Dan Stark of Caltech, the leader of the study. "As a result, we can see, for the first time, that a typical-sized young galaxy is spinning and slowly evolving into a spiral galaxy much like our own Milky Way," he says.The research, described in the October 9 issue of the journal Nature, provides a demonstration of the likely power of the future Thirty Meter Telescope (TMT), the first of a new generation of large telescopes designed to exploit AO.
Likewise, the Atacama Large Millimeter Array (ALMA), a large interferometer being completed in Chile, will provide a major step forward in mapping the extremely faint emission from cold hydrogen gas--the principal component of young, distant galaxies and a clear marker of cold molecular gas--compared to the coarser capabilities of present facilities. In their recent research, the Caltech-led team has provided a glimpse of what can be done with the superior performance expected of TMT and ALMA.
The key spectroscopic observations were made with the OSIRIS instrument, developed specifically for the Keck AO system by astrophysicist James Larkin and collaborators at the University of California, Los Angeles. Stark and his coworkers used the OSIRIS instrument to map the velocity across the source in fine detail, allowing them to demonstrate that it has a primitive rotating disk.
To aid in their analysis, the researchers combined data from the Keck Observatory with data taken at millimeter wavelengths by the Plateau de Bure Interferometer (PdBI), located in the French Alps. This PdBI instrument is sensitive to the distribution of cold gas that has yet to collapse to form stars. These observations give a hint of what will soon be routine with the ALMA interferometer.
"Remarkably, the cold gas traced by our millimeter observations shares the rotation shown by the young stars seen in the Keck observations. The distribution of gas seen with our amazing resolution indicates we are witnessing the gradual buildup of a spiral disk with a central nuclear component," explains coinvestigator Mark Swinbank of Durham University, who was involved in both the Keck and PdBI observations.
This work demonstrates how important angular resolution has become in ensuring progress in extragalactic astronomy. This will be the key gain of both the TMT and ALMA facilities.
"For decades, astronomers were content to build bigger telescopes, arguing that light-gathering power was the primary measure of a telescope's ability," explains Richard S. Ellis, Steele Family Professor of Astronomy at Caltech, a coauthor on the Nature study, and a member of the TMT board of directors. "However, adaptive optics and interferometry are now providing ground-based astronomers with the additional gain of angular resolution. The combination of a large aperture and exquisite resolution is very effective for studying the internal properties of distant and faint sources seen as they were when the universe was young. This is the exciting future we can expect with TMT and ALMA, and, thanks to the magnification of a gravitational lens, we have an early demonstration here in this study," he says.
SF State astronomer searches for signs of life on Wolf 1061 exoplanet
20.01.2017 | San Francisco State University
Molecule flash mob
19.01.2017 | Technische Universität Wien
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences