Black holes

The position of the three stellar black holes discovered so far in the Milky Way, represented in projection, thanks to the Gaia mission.

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An article published in the journal “Astronomy and Astrophysics Letters” reports the identification of a stellar black hole with a mass estimated to be approximately 33 times the Sun’s that was cataloged as Gaia BH3. A team of researchers used data collected by ESA’s Gaia space probe to find this black hole in the Milky Way’s halo, less than two thousand light-years from Earth. Its mass is remarkable for a stellar black hole and it has a companion, a very ancient star, as its age is estimated to be around 11 billion years.

Artist's impression of the GRB221009A gamma-ray burst with relativistic jets coming from the black hole at the center (Image courtesy Aaron M. Geller / Northwestern / CIERA / IT Research Computing and Data Services)

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An article published in the journal “Nature Astronomy” reports a study on the gamma-ray burst cataloged as GRB221009A, the brightest ever detected, which confirms that it was caused by the collapse of a massive star, which subsequently exploded in a supernova. A team of researchers led by Northwestern University used data collected with the James Webb Space Telescope and the ALMA radio telescope to obtain the information needed to support their conclusions. The mystery remains of the absence of traces of the generation of heavy elements such as platinum and gold, which they thought could be associated with supernovae that lead to very powerful gamma-ray bursts.

The area around Sagittarius A*, the supermassive black hole at the center of the Milky Way, seen in polarized light

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Two articles published in “The Astrophysical Journal Letters” report different aspects of a study of Sagittarius A*, or simply Sgr A*, the supermassive black hole at the center of the Milky Way, which led to the creation of an image in polarized light of the area around it. The Event Horizon Telescope (EHT) collaboration used again a combination of various radio telescopes to detect polarized light thanks to the fact that particles rotating around the magnetic field lines determine a polarization pattern perpendicular to it.

Una porzione di cielo fotografata dallo strumento NIRCam del telescopio spaziale James Webb con la galassia GN-z11 nel riquadro

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Two articles, one published in the journal “Nature” and one accepted for publication in the journal “Astronomy & Astrophysics”, report different aspects of a study of the galaxy GN-z11, one of the most distant known, which revealed the presence of the most distant and ancient black hole found so far. A team of researchers led by Roberto Maiolino of the University of Cambridge used the James Webb Space Telescope to examine GN-z11 finding traces of the activity of the supermassive black hole at its center. Those traces indicate that it’s devouring surrounding materials at a remarkable speed. Spectroscopic analyzes showed the presence of a clump of helium in the halo surrounding GN-z11 and no heavy elements, suggesting that first-generation stars may form in that halo.

The region of sky where quasar J0529-4351 is located. It was created from images forming part of the Digitized Sky Survey 2 while the inset shows the position of this quasar in the center in an image from the Dark Energy Survey.

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An article published in the journal “Nature Astronomy” reports the identification of the brightest and most voracious quasar discovered so far, cataloged as J0529-4351. A team of researchers used various instruments to understand that it wasn’t a nearby star but a primordial quasar we see as it looked over 12 billion years ago.

The researchers estimated that the mass of the supermassive black hole that powers it is about 17 billion times the Sun’s, and it’s devouring materials around it at a very high rate, about the mass of the Sun every day. The study of this record-breaking primordial quasar can help reconstruct the history of the early universe and the processes that led to it becoming what it is today.