Month: December 2019

Blazar variability

Active galactic nuclei (AGN) are supermassive black holes at the centers of galaxies that are accreting material. These AGN emit jets of charged particles that move at speeds close to that of light, transporting huge amounts of energy away from the central black hole region and radiating across the electromagnetic spectrum. Blazars are extreme examples of AGN in which the collimated jets are coincidentally aligned towards us. Blazar jets have two peak emission wavelengths, one that spans the range from the radio to the X-ray, the result of charged particle acceleration, and one at extremely short wavelength, high energy gamma ray bands usually (and somewhat controversially) attributed to the charged particles scattering infrared “seed” photons from a variety of other sources. All these bands manifest strong and unpredictable variability. Simultaneous, long-term observations across multiple bands therefore, by modeling the relative timing of flares and other variable emission, offer a valuable way to investigate the numerous possible physical mechanisms at work.

read more
Simulations show thousands of lakes in Himalaya Mountains at risk of flooding due to global warming

Three researchers with the University of Potsdam report that thousands of natural lakes in the Himalayas are at risk of bursting their moraines due to global warming and causing flooding downriver. In their paper published in Proceedings of the National Academy of Sciences, Georg Veh, Oliver Korup and Ariane Walz describe simulations they ran on lake models and what they showed.

read more
Nearly quantized conductance plateau of vortex mode in an iron-based superconductor

When a semiconducting nanowire is coupled to a superconductor, it can be tuned to topological quantum states thought to host localized quasiparticles known as Majorana Zero Modes (MZM). MZMs are their own antiparticles, with promising applications in topological quantum computing. Due to particle-antiparticle equivalence, MZMs exhibit quantized conductance at low temperatures. While many theoretical proposals exist to realize MZMs in solid state systems, their experimental realization is confronted by non-idealities.

read more
Extending El Niño event predictions to a year

A group of researchers from the Potsdam Institute for Climate Impact Research, Beijing Normal University and Justus-Liebig-Universität Giessen has found a way to predict El Niño events up to a year before they occur. In their paper published in the Proceedings of the National Academy of Sciences, the group describes their complexity-based approach to better predicting the seemingly random weather events.

read more
Wildfire modeling helps predict fires in Colombia

A new wildfire model helps predict where and when wildfires will start in the Aburrá Valley of Colombia. This research, presented earlier this month at the 2019 American Geophysical Union Fall Meeting in San Francisco, is helping local cities avoid the devastating environmental and health impacts of fires.

read more

Copyright © All right reserved.