Category Astronomy/Space

Mergers between Galaxies trigger activity in their Core

Two galaxies merging. Credit: Hubble Space Telescope

Active galactic nuclei (AGNs) play a major role in galaxy evolution. Astronomers from SRON and RuG have now used a record-setting sample of galaxies to confirm that galaxy mergers have a positive effect on igniting AGNs. They were able to compile about 10 times more pictures of merging galaxies than previous studies by using a machine-learning algorithm.

One of the bigger questions in astronomy is how galaxies evolve from clouds of gas and dust to the beautiful spiral structures observed in our galactic neighborhood. So-called active galactic nuclei (AGNs) comprise interesting research objects to answer part of the question, because there appears to be co-evolution between AGNs and galaxies...

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MAXI J1820+070: Black Hole Outburst caught on Video

Credits: X-ray: NASA/CXC/Université de Paris/M. Espinasse et al.; Optical/IR:PanSTARRS

Astronomers have caught a black hole hurling hot material into space at close to the speed of light. This flare-up was captured in a new movie from NASA’s Chandra X-ray Observatory.

The black hole and its companion star make up a system called MAXI J1820+070, located in our galaxy about 10,000 light years from Earth. The black hole in MAXI J1820+070 has a mass about eight times that of the sun, identifying it as a so-called stellar-mass black hole, formed by the destruction of a massive star. (This is in contrast to supermassive black holes that contain millions or billions of times the sun’s mass.)

The companion star orbiting the black hole has about half the mass of the sun...

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Astronomers create Cloud Atlas for Hot, Jupiter-like Exoplanets

exoplanet-clouds-450.jpg
Predicted cloud altitudes and compositions for a range of temperatures common on hot Jupiter planets. The range, in Kelvin, corresponds to about 800 to 3,500 degrees Fahrenheit, or 427 to 1,927 degrees Celsius. (Image by Peter Gao/UC Berkeley)

Giant planets in our solar system and circling other stars have exotic clouds unlike anything on Earth, and the gas giants orbiting close to their stars—so-called hot Jupiters—boast the most extreme.

A team of astronomers from the United States, Canada and the United Kingdom have now come up with a model that predicts which of the many types of proposed clouds, from sapphire to smoggy methane haze, to expect on hot Jupiters of different temperatures, up to thousands of degrees Kelvin.

Surprisingly, the most common type of cloud, expecte...

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The ‘Cow’ mystery strikes back: Two more Rare, Explosive Events captured

Artist’s illustration detailing the structure of FBOTs. Credit: Bill Saxton, NRAO/AUI/NSF

The ‘Cow’ is not alone; with the help of W. M. Keck Observatory on Maunakea in Hawaii, astronomers have discovered two more like it—the ‘Koala’ and a similar mysterious bright object called CSS161010. This trio of fast blue optical transients (FBOTs) appear to be relatives, all belonging to a highly-luminous family that has a track record for surprising astronomers with their fast, powerful bursts of energy.

The ‘Koala,’ which is a nickname derived from the tail end of its official name ZTF18abvkwla, suddenly appeared as a bright new source in the optical sky before disappearing within just a few nights...

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