Some of the newly found magnified objects are dimmer than the faintest ones seen in the legendary Hubble Ultra Deep Field, which is usually considered the deepest image of the Universe.
By combining both visible and near-infrared observations from Hubble’s Advanced Camera for Surveys (ACS) and Near Infrared Camera and Multi-Object Spectrometer (NICMOS), scientists searched for galaxies that are only visible in near-infrared light. They uncovered 10 candidates believed to lie about 13 billion light-years away (a redshift of approximately 7.5), which means that the light gathered was emitted by the stars when the Universe was still very young — a mere 700 million years old.
“These candidates could well explain one of the big puzzles plaguing astronomy today. We know that the Universe was reionised within the first 5-600 million years after the Big Bang, but we don’t know if the ionising energy came from a smaller number of big galaxies or a more plentiful population of tiny ones”, said Johan Richard, from the California Institute of Technology. The relatively high number of redshift 7.5 galaxies claimed in this survey suggests that most of the ionising energy was produced by dim and abundant galaxies rather than large, scarce ones.
“The challenge for astronomers is that galaxies beyond a distance of 13 billion light-years (past a redshift of 7) are exceedingly faint and are only visible in the near-infrared — just at the limit of what Hubble can observe” explained Jean-Paul Kneib from the Laboratoire d’astrophysique de Marseille. This new result was only made possible with some cosmic assistance in the form of gravitational lensing that magnified the light from the distant galaxies enough for Hubble to detect them. A firm confirmation of their distance was beyond even the capabilities of the 10-meter Keck telescope and must await powerful future ground-based telescopes.
First confirmed in 1979, gravitational lenses were predicted by Albert Einstein’s theory of General Relativity, a theory that allows astronomers to calculate the path of starlight as it moves through curved space-time. According to the theory, the bending of light is brought about by the presence of matter in the Universe, which causes the fabric of space-time to warp and curve.
Gravitational lensing is the result of this warping of spacetime and is mainly detected around very massive galaxy clusters. Due to the gravitational effect of both the cluster’s observable matter and hidden dark matter, the light is bent around the cluster. This bending of light allows the clusters in certain places to act as natural gravitational telescopes that give the light of faint and faraway objects a boost.
Where Earth-bound telescopes fail to detect such faint and distant objects due to the blurring introduced by the Earth’s atmosphere, a combination of Hubble’s location in space and the magnification of the gravitation lenses provides astronomers with a birds-eye view of these elusive objects.
This technique has already been used numerous times by Hubble and has helped astronomers to find and study many of the most distant known galaxies.
Lars Christensen | alfa
APEX takes a glimpse into the heart of darkness
25.05.2018 | Max-Planck-Institut für Radioastronomie
First chip-scale broadband optical system that can sense molecules in the mid-IR
24.05.2018 | Columbia University School of Engineering and Applied Science
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences