Galaxies

The dwarf galaxy ESO 495-21 (Image ESA/Hubble, NASA)

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An image captured by the Hubble space telescope shows the dwarf galaxy ESO 495-21, really small having an estimated total mass of around 10 billion solar masses, about 3% of the Milky Way. The astronomers’ interest in ESO 495-21 is due to the fact that, despite its small size, it’s of the starburst type, which means that it has a fast rate of star formation, and has at its center a supermassive black hole with a mass estimated at at least one million solar masses. It’s a case that could be similar to the first galaxies of the universe and supports the hypothesis that the dwarf galaxy formed around a black hole that already existed before.

A cosmic aurora between the Abell 0399 and Abell 0401 galaxy clusters

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An article published in the journal “Science” reports the identification of electromagnetic fields along a filament that crosses the approximately 10 million light years between the Abell 0399 and Abell 0401 galaxy clusters. A team of researchers led by Federica Govoni of the National Institute of Astrophysics, Cagliari, used the Low Frequency Array (LOFAR) radio telescope to carry out for the first time measurement of such a structure in radio waves.

The galaxy NGC 4485 altered by a cosmic clash

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A new image captured by the Hubble Space Telescope’s Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS) instruments portrays the galaxy NGC 4485. It’s an irregular galaxy, which means that its shape is not among the normal ones for galaxies, a consequence of its passage through a much larger neighbor, NGC 4490, which altered the balance inside it and among other things also started the formation of new stars.

The unexpected brightness of the earliest galaxies in the universe offers clues to a crucial moment in its evolution

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An article published in the journal “Monthly Notices of the Royal Astronomical Society” shows evidence that the oldest galaxies in the universe were brighter than expected. A team of researchers combined observations made with the Hubble and Spitzer space telescopes of galaxies that formed less than a billion years after the Big Bang and discovered an unexpected infrared brightness. That’s the consequence of the release of ionizing radiation and that can offer new clues to the epoch of reionization, a crucial moment in the history of the universe.

Thousands of images from the Hubble Space Telescope provide a wide view of the universe and its history

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A mosaic of images created by combining 7,500 images captured by the Hubble Space Telescope offers a portrait of a part of the universe containing 265,000 galaxies up to 13.3 billion light years away, which means that we see the most distant of them as they were about 500 million years after the Big Bang. The result was named the Hubble Legacy Field and also combines observations taken from various deep field campaigns of the past years at wavelengths ranging from ultraviolets to near infrareds. It also shows the universe that evolves over time.