Black Holes Can Cook for Themselves, Chandra Study Shows - UNIVERSE

Perseus Cluster: X-ray: NASA/CXC/SAO/V. Olivares et al.; Optical/IR: DSS; H-alpha: CFHT/SITELLE; Centaurus Cluster: X-ray: NASA/CXC/SAO/V. Olivaresi et al.; Optical/IR: NASA/ESA/STScI; H-alpha: ESO/VLT/MUSE; Image Processing: NASA/CXC/SAO/N. Wolk

Astronomers have taken a crucial step in showing that the most massive black holes in the universe can create their own meals. Data from NASA’s Chandra X-ray Observatory and the Very Large Telescope (VLT) provide new evidence that outbursts from black holes can help cool down gas to feed themselves.

This study was based on observations of seven clusters of galaxies. The centers of galaxy clusters contain the universe’s most massive galaxies, which harbor huge black holes with masses ranging from millions to tens of billions of times that of the Sun. Jets from these black holes are driven by the black holes feasting on gas.

These images show two of the galaxy clusters in the study, the Perseus Cluster and the Centaurus Cluster. Chandra data represented in blue reveals X-rays from filaments of hot gas, and data from the VLT, an optical telescope in Chile, shows cooler filaments in red.

The results support a model where outbursts from the black holes trigger hot gas to cool and form narrow filaments of warm gas. Turbulence in the gas also plays an important role in this triggering process.

According to this model, some of the warm gas in these filaments should then flow into the centers of the galaxies to feed the black holes, causing an outburst. The outburst causes more gas to cool and feed the black holes, leading to further outbursts.

This model predicts there will be a relationship between the brightness of filaments of hot and warm gas in the centers of galaxy clusters. More specifically, in regions where the hot gas is brighter, the warm gas should also be brighter. The team of astronomers has, for the first time, discovered such a relationship, giving critical support for the model.

This result also provides new understanding of these gas-filled filaments, which are important not just for feeding black holes but also for causing new stars to form. This advance was made possible by an innovative technique that isolates the hot filaments in the Chandra X-ray data from other structures, including large cavities in the hot gas created by the black hole’s jets.

The newly found relationship for these filaments shows remarkable similarity to the one found in the tails of jellyfish galaxies, which have had gas stripped away from them as they travel through surrounding gas, forming long tails. This similarity reveals an unexpected cosmic connection between the two objects and implies a similar process is occurring in these objects.

This work was led by Valeria Olivares from the University of Santiago de Chile, and was published Monday in Nature Astronomy. The study brought together international experts in optical and X-ray observations and simulations from the United States, Chile, Australia, Canada, and Italy. The work relied on the capabilities of the MUSE (Multi Unit Spectroscopic Explorer) instrument on the VLT, which generates 3D views of the universe.

NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

Read more from NASA’s Chandra X-ray Observatory.

Learn more about the Chandra X-ray Observatory and its mission here:

https://www.nasa.gov/chandra

https://chandra.si.edu

Visual Description

This release features composite images shown side-by-side of two different galaxy clusters, each with a central black hole surrounded by patches and filaments of gas. The galaxy clusters, known as Perseus and Centaurus, are two of seven galaxy clusters observed as part of an international study led by the University of Santiago de Chile.

In each image, a patch of purple with neon pink veins floats in the blackness of space, surrounded by flecks of light. At the center of each patch is a glowing, bright white dot. The bright white dots are black holes. The purple patches represent hot X-ray gas, and the neon pink veins represent filaments of warm gas. According to the model published in the study, jets from the black holes impact the hot X-ray gas. This gas cools into warm filaments, with some warm gas flowing back into the black hole. The return flow of warm gas causes jets to again cool the hot gas, triggering the cycle once again.

While the images of the two galaxy clusters are broadly similar, there are significant visual differences. In the image of the Perseus Cluster on the left, the surrounding flecks of light are larger and brighter, making the individual galaxies they represent easier to discern. Here, the purple gas has a blue tint, and the hot pink filaments appear solid, as if rendered with quivering strokes of a paintbrush. In the image of the Centaurus Cluster on the right, the purple gas appears softer, with a more diffuse quality. The filaments are rendered in more detail, with feathery edges, and gradation in color ranging from pale pink to neon red. 

By: Lee Mohon

Source: Black Holes Can Cook for Themselves, Chandra Study Shows - NASA 

Use of robotic hand exoskeleton helps pianists improve their playing speed

Hand exoskeleton robot attached to the digits of the right hand. The device can flex and extend the metacarpophalangeal joints of the individual digits. Credit: Shinichi Furuya

A team of roboticists at Sony Computer Science Laboratories Inc. and the NeuroPiano Institute, in Kyoto, reports that a robotic exoskeleton strapped to the top of a piano player's hand allowed it to control the player's fingers during speed exercises, leading to improvements in playing fast-moving piano tunes. In their study, published in the journal Science Robotics, the group conducted experiments with their exoskeleton hand robot with more than 100 trained piano players.

Prior research and anecdotal evidence have shown that most musicians reach a plateau in their playing ability after long periods of practice, especially for instruments that require high-speed dexterity like guitar and piano. In this new study, the researchers in Japan wondered if passive hand training with a robot could help musicians move beyond this plateau, allowing them to play better or faster. They recruited 118 trained pianists to take part in a series of experiments.

The exoskeleton they developed fits over the top of the hand and attaches to the fingers to keep it firmly in place and control finger movement. The finger movements in the exercises simulated the types that are used to play the piano. 

Fast and complex multi-finger movements generated by the hand exoskeleton. Credit: Shinichi Furuya

Each of the volunteers practiced playing pieces prior to the experiments until reaching their individual plateau levels. They then allowed the robot exoskeleton to conduct what the researchers call passive training, during which the robot controlled the fingers on just their right hand, moving them up and down in different patterns at different speeds.

Following the training, the volunteers were then asked to remove the exoskeleton and play the same pieces they had been practicing to see if there were any differences. The research teams found that the training had improved player performance, allowing the pianists to move beyond their plateau, most particularly for playing faster. They also found improvements in both hands despite training just one hand.

The team also conducted motor cortex tests before and after training and found that the training led to neuroplastic changes in the brain. 

by Bob Yirka , Tech Xplore

Source: Use of robotic hand exoskeleton helps pianists improve their playing speed