The COSMOS project, led by Nick Scoville at the California Institute of Technology, USA, used observations from several observatories including the Hubble Space Telescope, as well as the Spitzer Space Telescope, the XMM-Newton spacecraft, the Chandra X-ray Observatory, the Very Large Telescope (VLT), the Subaru Telescope and CFHT.
In this image, six examples of the rich diversity of 67 strong gravitational lenses found in the COSMOS survey. The lenses were discovered in a recently completed, large set of observations as part of a project to survey a single 1.6-square-degree field of sky (nine times the area of the full Moon) with several space-based and Earth-based observatories. Gravitational lenses occur when light travelling towards us from a distant galaxy is magnified and distorted as it encounters a massive object between the galaxy and us. These gravitational lenses often allow astronomers to peer much further back into the early Universe than they would normally be able to. The COSMOS project, led by Nick Scoville at the California Institute of Technology, used observations from several observatories including the Hubble Space Telescope, the Spitzer Space Telescope, the XMM-Newton spacecraft, the Chandra X-ray Observatory, the Very Large Telescope (VLT), and the Subaru Telescope. In total 67 gravitational lenses were found.
A team of European astronomers led by Jean-Paul Kneib (Laboratoire d’Astrophysique de Marseille) and Cécile Faure (Zentrum für Astronomie, University of Heidelberg) analysed the results from Hubble’s Advanced Camera for Surveys (ACS). From ACS high-resolution images, complemented by the extensive ground-based follow-up observations, astronomers have identified 67 strong gravitationally lensed galaxies. These were found around very massive galaxies that are usually elliptical or lenticular in shape and often exhibit a paucity of gas and dust without spiral arms or discs. The strong lensing produced by massive galaxies is much more common than the usual giant “arc” gravitationally lensed galaxies that Hubble has previously observed; but they are generally more difficult to find as they extend over a smaller area and have a wide variety of shapes.
Gravitational lensing occurs when light travelling towards us from a distant galaxy is magnified and distorted as it encounters a massive object between the galaxy and us. These gravitational lenses often allow astronomers to peer much further back into the early Universe than they would normally be able to.
The massive objects that create the lenses are usually huge clusters of massive galaxies. “We typically see the gravitational lens create a series of bright arcs or spots around a galaxy cluster. What we are observing here is a similar effect but on much smaller scale – happening only around a single but very massive galaxy,” says Jean-Paul Kneib.
Of the 67 gravitational lenses identified in the COSMOS survey, the most impressive lenses show the distorted and warped light of one or two background galaxies. At least four of the lenses give rise to Einstein rings, a complete circular image of a background galaxy, which is formed when the background galaxy, a massive foreground galaxy and the Hubble Space Telescope are all aligned perfectly.
Hubble astronomers went through a unique process to identify these incredible natural lenses. First, possible galaxies were identified from a galaxy catalogue, comprising more than two million galaxies. “We then had to look through each individual COSMOS image by eye and identify any potential strong gravitational lenses,” said Cécile Faure. Finally, checks were made to see if the foreground galaxy and the lensed galaxy were really different or just one galaxy with an odd shape. “With this sample of gravitational systems identified by the human eye, we now plan use the sample of lenses to train robot software to find more of these lenses across the entire Hubble image archive, and we may find even more strong lensing systems in the COSMOS field,” added Jean-Paul Kneib.
The new results confirm that the Universe is filled with gravitational lensing systems. Extrapolating these new findings to the whole sky, predicts no less than half a million similar lenses in total. The future prospects for finding more of these systems are thus excellent.
The study of these gravitational lenses will give astronomers a first-rate opportunity to probe the dark matter distribution around galactic lenses. Once astronomers find even larger numbers of these smaller, stronger lenses they can be used to create a census of galaxy masses in the Universe to test the predictions of cosmological models.
Lars Christensen | alfa
First Juno science results supported by University of Leicester's Jupiter 'forecast'
26.05.2017 | University of Leicester
Measured for the first time: Direction of light waves changed by quantum effect
24.05.2017 | Vienna University of Technology
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy