galaxy formation tagged posts

The position of Virgo I in the constellation of Virgo (left). The right panel shows a density map of Virgo I’s member stars in a 0.1 deg x 0.1 deg area, based on the stars located inside the green zone in the color-magnitude diagram of Virgo I shown in Figure 4. The color range from blue -> white -> yellow -> red indicates increasing density. (Credit: Tohoku University/National Astronomical Observation of Japan)

An international team has found an extremely faint dwarf satellite galaxy of the Milky Way. The team’s discovery is part of the ongoing Subaru Strategic Survey using Hyper Suprime-Cam. The satellite, named Virgo I, lies in the direction of the constellation Virgo. At the absolute magnitude of -0.8 in the optical waveband, it may well be the faintest satellite galaxy yet found...

Age structure of the Milky Way’s halo

Using colors to identify the approximate ages of >130,000 stars in the Milky Way’s halo, Notre Dame astronomers have produced the clearest picture yet of how the galaxy formed more than 13.5 billion years ago. The chronographic (age) map supports a hierarchical model of galaxy formation. That model, developed by theoreticians over the past few decades, suggests that the Milky Way formed by merging and accretion of small mini-halos containing stars and gas, and that the oldest of the Milky Way’s stars are at the center of the galaxy and younger stars and galaxies merged with the Milky Way, drawn in by gravity over billions of years...

What is the origin of gold, silver, platinum? Credit: © alexphoto71 / Fotolia

The origin of many of the most precious elements on the periodic table, such as gold, silver and platinum, has perplexed scientists for >6 decades. Now a recent study has an answer, evocatively conveyed in the faint starlight from a distant dwarf galaxy. In a roundtable discussion The Kavli Foundation spoke to 2 of the researchers behind the discovery about why the source of these heavy elements, collectively called “r-process” elements, has been so hard to crack.

“Understanding how heavy, r-process elements are formed is one of hardest problems in nuclear physics,” said Assistant/Prof Anna Frebel, MIT...