Dr. Sadun

     With the assistance of collaborators (including our very own Dr. Asadi-Zeydabadi), we investigate the behavior of quasars and other active galaxies by taking images of these objects at various points in time, and tracking their variations in brightness.  We take these images remotely, from telescopes all over the world, download the images, and reduce and measure them with proprietary software here on campus.  We produce light curves and analyze them singly, or combined them with the data of others at other wavelengths, particularly high energy x-rays and gamma-rays.  From analyzing the kinematics and dynamics of these objects, we learn about the distribution of matter, existence of jets, and size and mass of the supermassive black holes and accretion discs that power these phenomena.

     Below is shown the microvariability of BL Lacertae, modeled as an active galaxy whose jet is pointed nearly at us, but which varies slightly in position giving us the variability.


     We have recently published a paper on Mkn 501, another highly variable object, as shown below.  Also shown in detail is a plot of a particular microvariable event.