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    Microlensing tagged posts

    NASA Space Telescopes Pinpoint elusive Brown Dwarf

    November 16, 2016, Categories  Astronomy/Space

    This illustration depicts a newly discovered brown dwarf, an object that weighs in somewhere between our solar system's most massive planet (Jupiter) and the least-massive known star. Credit: NASA/JPL-Caltech

    This illustration depicts a newly discovered brown dwarf, an object that weighs in somewhere between our solar system’s most massive planet (Jupiter) and the least-massive known star. Credit: NASA/JPL-Caltech

    In a first-of-its-kind collaboration, NASA’s Spitzer and Swift space telescopes joined forces to observe a microlensing event, when a distant star brightens due to the gravitational field of at least one foreground cosmic object. This technique is useful for finding low-mass bodies orbiting stars, such as planets. In this case, the observations revealed a brown dwarf.

    Brown dwarfs are thought to be the missing link between planets and stars, with masses up to 80 times that of Jupiter...

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    Hypervariable Galactic Nuclei

    October 31, 2016, Categories  Uncategorized

    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 of blue, hypervariable galaxies; the origin of the variability is uncertain but might in some cases be due to microlensing. Credit: PanSTARRS

    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...

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    Einstein’s Cross under the Gravitational Microlens

    December 22, 2015, Categories  Astronomy/Space

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

    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...

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