After the interaction of a xenon atom with two photons from an attosecond pulse (purple), the atom is ionized and multiple electrons (green balls) are ejected. This two-photon interaction is made possible by the latest achievements in attosecond technology. (Image: Max-Planck-Institut für Quantenoptik)

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short ...

Figure 1: The Milky Way galaxy, perturbed by the tidal interaction with a dwarf galaxy, as predicted by N-body simulations. The locations of the observed stars above and below the disk, which are used to test the perturbation scenario, are indicated.

An international team of astronomers led by the Max Planck Institute for Astronomy (MPIA) has made a surprising discovery about the birthplace of groups of stars located in the halo of our Milky Way galaxy. These halo stars are grouped together in giant structures that orbit the center of our galaxy, above and below the flat disk of the Milky Way. Researchers thought they may have formed from debris left behind by smaller galaxies that invaded the Milky Way in the past.

But astronomers now have compelling evidence showing that some of these ha...

Possible roles of magnesium in vitamin D synthesis. Magnesium is involved in both activation and inactivation of vitamin D. Abbreviations: 1,25(OH)2D, 1,25-dihydroxyvitamin D (biologically active form); 24,25(OH)2D, 24,25-Dihydroxyvitamin D; 25(OH)D, calciferol (inactive form); D2, vitamin D2 (from nonanimal sources); D3, vitamin D3 (from animal sources); DBP, vitamin D–binding protein; Mg, magnesium; VDR, vitamin D receptors.

Up to 50% of US population is magnesium deficient. Vitamin D can’t be metabolized without sufficient magnesium levels, meaning Vitamin D remains stored and inactive for as many as 50% of Americans. In addition, Vitamin D supplements can increase a person’s calcium and phosphate levels even while they remain Vitamin D deficient...

Image of the Whirlpool galaxy, or M51. X-ray light seen by NASA’s Chandra X-ray Observatory is shown in purple, and optical light from NASA’s Hubble Space Telescope is red, green and blue. The ultraluminous X-ray source, or ULX, in the new Caltech-led study is indicated. Credit: NASA/CXC/Caltech/M.Brightman et al.; Optical: NASA/STScI

Astronomers find new clues in galactic mystery of ultraluminous sources of X-rays. In the 1980s, researchers began discovering extremely bright sources of X-rays in the outer portions of galaxies, away from the supermassive black holes that dominate their centers. At first, researchers thought these cosmic objects, called ultraluminous X-ray sources, or ULXs, were hefty black holes with more than ten times the mass of the sun...