Quasars are the most luminous sources in the Universe, but the precise mechanism that leads to this prodigious luminosity is in open question. The physical structure of quasars is notoriously difficult to study since all known quasars are located billions of light years from Earth. The angular sizes they subtend at these impossibly large distances are simply too small to be resolved with any conventional telescopes.
My collaborators and I have succeeded in skirting this limitation by exploiting a small subset of quasars that happen to be lensed by galaxies in the foreground. In cooperation with the US Naval Observatory, Flagstaff AZ, we have been monitoring a number of lensed quasars at optical and infrared wavelengths for over 15 seasons. We have complemeted these ground-based observations with ultraviolet (UV) imagery from the Hubble Space Telescope and X-ray imagery from the Chandra X-Ray Observatory to yield empirical measurements of the sizes of the X-ray, UV, optical and infrared contintinuum emission regions in the systems we are monitoring.
Hubble Space Telescope Image of the Gravitationally Lensed Quasar WFI2033-4723
My postdoc and I typically advise 3-4 midshipmen per semester in research classes supporting our work on gravitationally lensed quasars. I have advised two Trident Scholars, Michael Eyler (USNA 2008) and Gregory Hyer (USNA 2018), both of whom earned co-authorship on several refereed journal articles. I have also advised four Bowman Scholars. I strongly encourage interested midshipmen to contact me via email or to simply stop by my office to discuss possibilties for future research.
MIDN Laura Gorinski, Shane Martin and Roman Klimchuk assisting with lensed quasar observations at the US Naval Observatory in Flagstaff, AZ.
I am very grateful for several cycles of funding and observtional data from the National Science Foundation, the Chandra X-Ray Observatory and the Space Telescope Science Institute.
Selected Recent Publications:
Click here for a cool animation from this exciting project, and click the image below for an explanation!
Near Infrared and Optical Continuum Emission Region Size Measurements in the Gravitationally Lensed Quasars Q0957+561 and SBS0909+532
See my Google Scholar Page for a full list of publications.
U.S. Naval Academy
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