quasar tagged posts

Two of the authors of this paper: Evencio Mediavilla (IAC) and Jorge Jímenez Vicente (UGR). Credit: Two of the authors of this paper: Evencio Mediavilla (IAC) and Jorge Jímenez Vicente (UGR).

Researchers have succeeded in measuring the inner edge of the disk of matter that orbits around a supermassive black hole in a quasar > 5B light yrs from earth(an object the size of our solar system that emits as much energy as a whole galaxy). It’s the most accurate measure achieved until now of such a small and distant object, and it has been achieved thanks to the so-called gravitational microlensing effect, caused by stars belonging to a galaxy between us and the quasar, and which may magnify tiny regions within the quasar.

In particular, they have managed to measure the inner edge of the disk o...

This image shows the elliptical galaxy NGC 4889 in front of hundreds of background galaxies, and deeply embedded within the Coma galaxy cluster. Well-hidden from human eyes, there is a gigantic supermassive black hole at the center of the galaxy. Credit: NASA & ESA

The placid appearance of NGC 4889 can fool the unsuspecting observer. But the elliptical galaxy harbours one of the most supermassive black holes ever discovered. Located ~300 million light-years away in the Coma Cluster, the giant elliptical galaxy NGC 4889, the brightest and largest galaxy in this image has a black hole that is 21 billion times the mass of the Sun. The event horizon has a diameter of ~130 billion kilometres. This is about 15X the diameter of Neptune’s orbit from the Sun...

Einstein’s Cross. Credit: Image courtesy of Asociación RUVID

The Spanish interuniversity group has obtained precise measurements for the innermost region of a disc of matter in orbital motion around a supermassive black hole tucked inside the quasar known as Einstein’s Cross (Q2237-0305). It constitutes the most precise set of measurements achieved to date for such a small and distant object, and was made possible thanks to years of monitoring as part of the OGLE and GLITP gravitational microlensing projects, which have had their lenses trained on this quasar for 12 and 9 years, respectively.

Typically, astronomers can only detect bright objects that emit a lot of light or large objects that block background light...

OU astrophysicist and his Chinese collaborator used observations from NASA’s Hubble Space Telescope find two supermassive black holes in Markarian 231. Credit: Space Telescope Science Institute, Baltimore, Maryland

The discovery of 2 supermassive black holes – one larger one and a second, smaller one – are evidence of a binary black hole and suggests that supermassive black holes assemble their masses through violent mergers.

Professor Dai and Lu looked at UV radiation emitted from the center of the Mrk 231 from Hubble observations, then applied a model developed by Lu to the spectrum of the galaxy. As a result, they were able to predict the existence of the binary black holes in Mrk 231.

“We are extremely excited about this finding because it not only shows the existence of a close binary...