Observations of a cluster of galaxies not too far from home have revealed that the cannibalistic galaxy at the centre of the cluster might be the most massive one in our local universe.

Images of Abell 3827 from the Gemini Observatory. Gemini Legacy Image: R. Carrasco et al., Gemini Observatory/AURA

The galaxy ESO 146-IG 005 at the centre of the galaxy cluster Abell 3827 has been known for over a decade to be cannibalistic, but astronomer Rodrigo Carrasco says, “The magnitude of its appetite has not been fully appreciated.” Carrasco and his colleagues at the Gemini Observatory‘s South telescope in Chile used the recent discovery of the gravitational lens around the cluster to conclude that the galaxy is nearly 30 trillion times the mass of Sol, our sun.

Line diagram of light bending around a mass. Image credit: Michael Sachs

Gravitational lensing is observed when light from a distant star or galaxy bends around a closer star or galaxy, sometimes giving the illusion of being in more than once place at a time. Often, the image of the star or galaxy observed will appear elongated. The bending of light is caused by the distortion of local spacetime by a massive object (see images). These apparent images sometimes form what are called Einstein’s rings.

The gravitational lens around the cluster, located 1.4 billion light years away from us, gave astronomers a value for the mass of the central galaxy that was 10 times higher than estimates using X-rays. “Assuming our model is correct, this is by far the most massive galaxy known in our local universe,” Carrasco said.

The two background galaxies observed lie at distances of 2.7 billion light years (labelled A, in the first image) and 5.1 billion light years (labelled B) away from us.

How Einstein's rings are formed. Image credit: NASA

The results, to be published in The Astrophysical Journal Letters¹, are very important, particularly to understand the growth of elliptical galaxies. These galaxies are thought to acquire most of their mass by merging with other galaxies or by consuming them over the course of time. Cannibalistic galaxies such as ESO 146-IG 005 can grow to tremendous sizes by consuming their neighbours.

Michael West, an astronomer from the European Southern Observatory, who first observed the cannibalistic behaviour in 1998, said, “This unabashed cannibal is something of a messy eater, with the partially digested remains of at least four smaller galaxies still visible near its centre. Eventually this galaxy will grow even bigger judging by the number of nearby galaxies already within its gravitational grasp.”

1. E. R. Carrasco, P. L. Gomez, T. Verdugo, H. Lee, R. Diaz, M. Bergmann, J. E. H. Turner, B. W. Miller, & M. J. West (2010). Strong Gravitational Lensing by the Super-massive cD Galaxy in Abell
   3827 The Astrophysical Journal Letters arXiv: 1004.5410v1

India sent a team of students to the International Sustainable World (Energy, Engineering and Environment) Project [I-SWEEEP] Olympiad for the first time this year. The Olympiad was held between 14 April and 19 April this year. I spoke to Dr Arnab Bhattacharya, co-chair of the IRIS Scientific Review Committee that selects and guides the students, to ask him about the experience.

Image Credit: I-SWEEEP

First images from NASA’s sun observation spacecraft

NASA’s Sun Dynamics Observatory, the first mission of the Living with a Star Program, has sent back the first high-resolution photographs of our sun, Sol. The photographs, with a resolution ten times better than high-definition television, will help scientists study with greater detail the influence the sun has on the earth.

The SDO was launched on 11 February this year and is expected to revolutionise our understanding of the processes of the sun, many of which relate to the sun’s magnetic field. The magnetic field is responsible for coronal mass ejections that cause magnetic storms in the earth’s atmosphere.

New image from the SDO. Image credit: NASA

Richard Fisher, director of the Heliophysics Division at NASA headquarters in Washington, D.C. said, “SDO will change our understanding of the sun and its processes, which affect our lives and society. This mission will have a huge impact on science, similar to the impact of the Hubble Space Telescope on modern astrophysics.”

For more pictures and videos, visit the SDO’s official image and video gallery.

Scientists observe transparency in artificial atom

Scientists working at the RIKEN Advanced Science Institute near Tokyo and the University of Loughborough in the UK have successfully observed the phenomenon of electromagnetically induced transparency (EIT) in artificial atoms, made of a superconducting loop.

The phenomenon, so far observed only in atomic gases, requires the atoms to have three energy levels where one specific pair of levels cannot have a transition. In the given artificial atom, the energy levels were the three lowest ones – 1, 2 and 3 – with no transition allowed between levels 1 and 3, reports physicsworld.com.

Scientist Abdufarrukh Abdumalikov and his colleagues then fired “probe” microwaves with energy equal to the transition between levels 1 and 2, inducing oscillations between those levels. Most of the microwaves are reflected as a result of this oscillation. However, when “control” microwaves with an energy corresponding to the transition between levels 2 and 3 were fired, the oscillations due to these microwaves interfered destructively with the first oscillations. This causes the probe light to pass through the “atom”.

The results were published in the pre-print repository arXiv.org. The observation has far-reaching implications for the field of quantum information technology, as the scientists hope the device that could act like a switchable mirror for microwaves may one day operate in optical wavelengths.

Smallest 3D map of world created

A 3D map – so tiny that more than 250 million maps could fit on a sheet of A4 paper – has been developed by IBM scientists from three countries, reports PopSci.com. The results were published in the journals Science and Advanced Materials.

The miniscule map, which measures 22 micrometres by 11 micrometres, was created by scratching at the surface of a polymer substrate using a tiny heated silicon tip. Urs Duerig, one of the scientists on the team, said they realised that, instead of adding material to the existing substrate, it might be possible to create 3D shapes by removing bits of the material.

Smallest lens-less microscope developed

A UCLA assistant professor has used a lens-less imaging technology he developed to create a very small microscope that could be used to monitor diseases like malaria and tuberculosis, reports PhysOrg.com. Aydogan Ozcan, an engineer, had developed the LUCAS (Lens-less Ultra-wide-field Cell Monitoring Array platform based on Shadow imaging) technology that generates a holographic image using a light-emitting diode (LED) as a light-source and a digital sensor array to record the images.

The design of the microscope, with few movable parts and a large aperture, makes it suitable for use in remote areas with relative ease. It needs to be connected via USB to a smartphone or laptop for power. The computer can analyse the images automatically, making the device user-friendly to non-technicians.

In addition, the tiny microscope that weighs just 46 grammes can be modified to provide density information of the sample being analysed.

Ozcan’s report was published in the journal Lab on a Chip.

Sasers developed!

Two groups of scientists have independently developed sound lasers, or sasers, that emit sound waves that are in phase with one another and can be focused in a given direction. The saser, which gets its name from Sound Amplification and Stimulated Emission of Radiation, has been developed by scientists at the University of Nottingham in the UK as well as at the California Institute of Technology (Caltech) in the US.

Both teams developed the sasers at different frequencies, indicating that they could be devised to work over a range of frequencies. In the same way that light has a wave and particle nature, sound can be thought of as having a particle nature represented by “phonons”. The research, published in Physical Review Letters, has been reported in physicsworld.com.

Van der Waals force may hold asteroids together

The Eros asteroid. Photo credit: NASA

Scientists studying the dusty surfaces of asteroids have suggested that the force holding them together might be the very same van der Waals force that is responsible for interactions between atoms and molecules. Daniel Scheeres and his colleagues from the University of Colorado in the US, and Michael Swift from the University of Nottingham in the UK compared all the forces that might hold an asteroid together. The findings were published in the online preprint archive, arXiv.org.

The suggestion, reported in physicsworld.com might sound surprising, but the two potential forces that may act on the particles – gravity and the van der Waals force – behave in different ways. Gravity is proportional to the mass of the particles, where as the van der Waals force changes according to the surface area. Based on their study, the researchers concluded that gravity was not effective in binding the rocks observed in smaller asteroids.

Physicists may have discovered a new phase of liquid hydrogen

Scientists conducting simulations of the molecular-to-atomic transition in liquid hydrogen have found evidence for a previously unknown liquid phase. Isaac Tamblyn from Dalhousie University in Halifax, Canada along with Stanimir A. Bonev also observed some intriguing structural characteristics of liquid hydrogen.

Tamblyn told PhysOrg.com about the simulation, and how it was conducted. They discovered the reasons behind certain characteristics of hydrogen, such as the fact that liquid hydrogen is denser than solid hydrogen. The research and the information obtained, presented in Physical Review Letters, suggest that physicists might have to revise equations of the properties of hydrogen as well as change the planetary models that we currently use.

One step closer to quantum computing

Physicists at the University of Wisconsin-Madison in the US have successfully created a circuit using two rubidium atoms, in an experiment that demonstrates the possibility of using atoms to build quantum computers.

Professors Mark Saffman and Thad Walker were able to take advantage of a seven-millionths-of-a-second window to build a controlled-NOT (C-NOT) gate, a circuit important for quantum computing. The significance of the experiment lies in the use of neutral atoms instead of charged ions that had been used previously. Since atoms do not normally interact with each other as ions do, more of them can be arranged together in a small region. Read the original report on PhysOrg.com.

Strange fluctuating magnetic waves detected in superconductors

The Meissner effect: a magnet levitating over a superconductor. Photo credit: Mai-Linh Doan

Researchers at Brown University in the US and others in France have studied for the first time what happens to electrons of a superconductor that are subjected to a magnetic field. Vesna Mitrovic and colleagues found that electrons in a superconducting material form strange, fluctuating magnetic waves under certain conditions.

It has been known for many years that there exists a relationship between magnetism and superconductivity (see image of Meissner effect), but the reason behind this relationship continued to baffle scientists. The research, mentioned in Science Daily, found that electrons in the superconducting material were tilted at various angles on their imaginary axes, and moved in a repeating pattern resembling waves. Most interestingly, the waves appeared to fluctuate under certain conditions. The scientists now hope to study why these fluctuations occur.

New material may revolutionise all-optical switching and computing

Scientists at Georgia Tech in the US have demonstrated a new class of material using molecules that could help develop all-optical switching devices. These devices would not require the signals to be converted from optical to electrical, then back again. These devices are essential for developing low-power, high-speed communications and computing.

Professors Seth Marder and Joseph Perry told PhysOrg.com about their work, which was reported in the 18 February edition of Science Express.

Cold-welding of gold and silver nanowires observed

Gold nanowires, seen under a Scanning Electron Microscope. Photo credit: Thomas Mårtensson/Kristian Mølhave

Scientists at Rice University in the US have observed cold welding at the nano-scale for the first time. Jun Lou and his team came across this phenomenon by accident, when they were studying the tensile strength of gold nanowires.

The results, reported in Nature Nanotechnology, show that gold and silver nanowires of a thickness between three-billionths and ten-billionths of a metre bond with one another without the application of heat and without a loss of their electrical or mechanical properties. The welded wires never broke at the same spot when the researchers tried to pull them apart, proving the strength of the bonds. Read the original article here.

Crystal tech could give us 3D displays

Researchers at the National University of Singapore have developed a method of controlling the growth of certain crystals that have useful optical properties. Xiaogang Liu and his colleagues used a process called doping where certain “impurities” are intentionally added to a substance for the favourable properties it lends. They successfully used elements from the lanthanide group to dope the crystal, allowing them to adjust the structure, size and light emission spectra of the crystals.

Because of its interesting optical properties, scientists believe that these crystals could be used to develop 3D displays. The discovery was published in Nature and was reported in physicsworld.com.