Margaret M. Hanson, Ph.D.
Professor of Physics, Associate University Dean

    UC Physics


    Massive Stars and Massive Stellar Clusters

    My research interests are varied. I spent most of my earlier research career working on massive stars, particularly very young ones. Over a decade ago, I devised a spectroscopic method (briefly illustrated here) which allows more precise measurements to be made of very young massive stars that are usually too heavily shrouded at optical wavelengths to be properly studied (Hanson 1995; Hanson, Conti & Rieke 1996, Hanson, Luhman & Rieke 1998a). This technique allows me to directly study and determine the physical characteristics of very young massive stars despite very high line of sight extinction (Hanson, Howarth & Conti 1997; Watson & Hanson 1998).

    Graduate Student, Randa A'sad &
  Margaret Hanson

    Later, it became obvious that very massive stars, even fully formed and no longer so young, might also experience great line of sight extinction purely due to their distance in the Milky Way galaxy. in 2003 I postulated that our Milky Way galaxy could quite possibly contain tens of extremely massive star clusters (masses > 104 solar mass), yet we had no clear means for detecting them (Hanson (2003). With collaborators Jura Borissova, Rudy Kurtev (Universidad Valparaiso, Chile) and Valentin Ivanov (ESO-Santiago), and greatly aided through the VVV Survey collaboration (P.I.s Dante Minniti and Phil Lucas) we began applying near-infrared observational methods to detect and characterize massive stellar clusters deep within our galaxy.

    The image to the right shows me with my PhD graduate student, Randa Asa'd, as we finish a night observing with the SOAR Telescope on Cerro Pachon, Chile, in June 2010.


    Stellar Cluster Simulations

    Through collaborations with, Dr. Bogdan Popescu, I have expanded my research interests to include image simulations of stellar clusters. These simulations allow one to better constrain the properties of resolved clusters, and more accurately predict integrated colors of unresolved, intermediate mass stellar clusters. To learn more about MASSCLEAN, the software program Dr. Popescu has developed, you should go here:

    Presentations I have made discussing/presenting MASSCLEAN that are available online are given here:

    For a professional audience: Click here for a quicktime .MOV file (NOTE: 146 MB)
    This talk was given Nov 23rd, 2010 at The Australian Astronomical Observatories (AAO), Sydney.

    For a more general science audience: click here for streaming .WMV file
    This talk was given Oct 12th, 2010, for the Sigma Xi Annual Banquet