quasar tagged posts

An illustration of the binary black hole system in OJ287. The predictions of the model are verified by observations. Credit: Gary Poyner, UK

An international team using several optical telescopes and NASA’s SWIFT X-ray telescope. The rotational rate of this massive black hole is 1/3 of the maximum spin rate allowed in General Relativity. This 18 billion solar mass heavy black hole powers a quasar OJ287 which lies about 3.5 billion light years away from Earth. This quasar lies very close to the apparent path of the Sun’s motion on the celestial sphere as seen from Earth, where most searches for asteroids and comets are conducted. Therefore, its optical photometric measurements already cover more than 100 years...

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...