Black holes

NGC 5194 and NGC 5195

An article submitted for publication in the journal “Monthly Notices of the Royal Astronomical Society” describes a research on the supermassive black hole at the center of the galaxy NGC 5195, which is undergoing some sort of indigestion. Using data collected with various telescopes, a team of astronomers at the University of Manchester discovered that the black hole causes chaotic events in its galaxy. Among the causes there’s its interaction with a much larger galaxy called NGC 5194 or Whirlpool galaxy.

Two supermassive black holes seen by VLBA (Image Bansal et al., NRAO/AUI/NSF.)

An article published in “The Astrophysical Journal” describes the discovery of the first pair of supermassive black holes orbiting each other at the center of the galaxy hosting them, called 0402+379. A team of astronomers used the Very Long Baseline Array (VLBA) radio telescope to locate the two black holes about 750 million light years from Earth. Their combined mass is about 15 billion times the Sun’s.

Chandra Deep Field-South and illustration of a supermassive black hole (Image X-ray: NASA/CXC/Univ. of Rome/E.Pezzulli et al. Illustration: NASA/CXC/M.Weiss)

An article published in the journal “Monthly Notices of the Royal Astronomical Society” describes a research about the growth mechanisms of supermassive black holes. A team of six Italian researchers led by Edward Pezzulli, a PhD student of the National Institute for Astrophysics (INAF) in Rome proposed a model that predicts that these objects can reach masses even billions of times the Sun’s not with a steady growth but with periodic “meals” that are very quick during whith they swallow huge amounts of materials.

The area where the star N6946-BH1 used to be before and after its disappearance (Image NASA/ESA/C. Kochanek (OSU))

An article published in the journal “Monthly Notices of the Royal Astronomical Society” describes the discovery of a massive star called N6946-BH1 that collapsed and seems to have formed a black hole directly without exploding into a supernova. A team of astronomers led by Christopher Kochanek used the Large Binocular Telescope (LBT) in Arizona and NASA’s Hubble and Spitzer space telescopes to observe for the first time this phenomenon, which could explain why there are less supernovae than expected.

A comparison between supermassive black holes in a normal galaxy and in one involved in a galaxy merger (Image National Astronomical Observatory of Japan)

An article published in the journal “Monthly Notices of the Royal Astronomical Society” describes the effects that a merger between two galaxies can have on a supermassive black hole at the center of a galaxy involved in that process. A team of researchers led by Claudio Ricci used especially NASA’s NuSTAR space telescope to study how in the last stages of galactic merger gas and dust fall towards a black hole enshrouding it and generating an active galactic nucleus.