Kategorie: Kosmologie

Head-on collision explains Andromeda’s strange shape

A two-decade-long riddle about the bizarre shape of the Milky Way’s nearest spiral-shaped galaxy, Andromeda, has been solved, suggests a new study. Instead of having the flat plane and outflung arms that are the hallmarks of a mature spiral galaxy, Andromeda has a warped plane and several rather chaotic, overlapping outer rings. The reason, according to an international team of astronomers, is that Andromeda suffered a head-on collision with a smaller galaxy some 210 million years ago. The evidence comes from infrared images taken by NASA’s Spitzer Space Telescope. They show a previously hidden, tilted second ring that protrudes from the heart of the galaxy. This ring is likely to be the shockwave of gas and dust from a colossal collision. The theory has been put to the test in a computer simulation. It suggests a dwarf galaxy called M32 probably drove straight into the heart of Andromeda.

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Images

Galaxy caught in the making

New Hubble images have provided a dramatic glimpse of a large massive galaxy under assembly as smaller galaxies merge. Hubble observations of the galaxy MRC 1138-262, nicknamed the „Spiderweb Galaxy“, have shown dozens of star-forming satellite galaxies in the actual process of merging.
https://esahubble.org/news/heic0614/

Scientists Nudge Closer to the Edge of a Black Hole

NASA scientists and their international partners using the new Japanese Suzaku satellite have collected a startling new set of black hole observations, revealing details of twisted space and warped time never before seen with such precision. The observations include clocking the speed of a black hole’s spin rate and measuring the angle at which matter pours into the void, as well as evidence for a wall of X-ray light pulled back and flattened by gravity.
https://www.nasa.gov/centers/goddard/news/topstory/2006/spinning_blackhole.html

Supernova radioisotopes show sun was born in star cluster

The death of a massive nearby star billions of years ago offers evidence the sun was born in a star cluster, say astronomers at the University of Illinois at Urbana-Champaign. Rather than being an only child, the sun could have hundreds or thousands of celestial siblings, now dispersed across the heavens. In a paper accepted for publication in the Astrophysical Journal, astronomy professors Leslie W. Looney and Brian D. Fields, and undergraduate student John J. Tobin take a close look at short-lived radioactive isotopes once present in primitive meteorites. The researchers‘ conclusions could reshape current theories on how, when and where planets form around stars.

https://news.illinois.edu/view/6367/206848

Abstract @ arXiv.org

Supernova Debris in the Solar System

Astronomers see inside a quasar for the first time

For the first time, astronomers have looked inside quasars – the brightest objects in the universe – and have seen evidence of black holes. The study lends further confirmation to what scientists have long suspected – that quasars are made up of super-massive black holes and the super-heated disks of material that are spiraling into them. The results of the Ohio State University-led project was reported on Thursday at the meeting of the American Astronomical Society (AAS) High Energy Astrophysics Division in San Francisco.
Research News Story @ Ohio State University