Microlensing tagged posts

Image of the gravitational lens RX J1131-1231 galaxy with the lens galaxy at the center and four lensed background quasars. It is estimated that there are trillions of planets in the center elliptical galaxy in this image. Credit: University of Oklahoma

A University of Oklahoma astrophysics team has discovered for the first time a population of planets beyond the Milky Way galaxy. Using microlensing – an astronomical phenomenon and the only known method capable of discovering planets at truly great distances from the Earth among other detection techniques – OU researchers were able to detect objects in extragalactic galaxies that range from the mass of the Moon to the mass of Jupiter.

Xinyu Dai, professor in the Homer L...

A photo of the PanSTARRS (Panoramic Survey Telescope & Rapid Response System) telescope in Hawaii. Astronomers have used a sky survey from this facility to identify a class of blue, hypervariable galaxies; the origin of the variability is uncertain but might in some cases be due to microlensing. Credit: PanSTARRS

Extreme variability in the intensity of the optical light of galaxies, by factors of 2 or more, is of great interest to astronomers. It can flag the presence of rare types of supernovae, for example, or spot sudden accretion activity around quiescent black holes or around the supermassive black hole at the galaxy’s nucleus. In recent years systematic searches for such variability have been made using instruments that can survey wide swaths of the sky...

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...