The next meeting of the National Capital Astronomers will be held Saturday, March 2, at 7:30 P.M. in the Lipsett Amphitheater of the Clinical Center (building 10) at the National Institutes of Health (NIH). Eli Dwek is an astrophysicist in the Infrared Astrophysics Branch of the Laboratory for Astronomy and Solar Physics (LASP) at the NASA/GSFC (National Aeronautics and Space Administration/Goddard Space Flight Center). He is a member of the COBE (COsmic Background Explorer) Science Working Group, working primarily on the interpretation of the data obtained by the Diffuse Infrared Background Experiment (DIRBE) on board the COBE satellite. His research areas of interest include the origin of the cosmic infrared background, the large scale distribution of stars and dust in the Milky Way Galaxy, and studies of interstellar dust. Eli Dwek received his graduate degree in physics and mathematics at the Hebrew University in Jerusalem, Israel (1973), and his Ph. D. in astronomy from Rice University in Houston, Texas (1977). He was a postdoctoral fellow at Caltech, and joined NASA in 1983.
The speaker Eli Dwek wrote the following abstract for a talk of similar title, ``In Pursuit of the Cosmic Infrared Background,'' given at the University of Maryland.
The cosmic infrared background (CIB) consists of the cumulative emissions from pregalactic objects, protogalaxies, and evolving galaxies throughout the history of the universe. The light from these objects is partially redshifted and partially absorbed and reradiated by dust into the infrared (IR) wavelength region. The Diffuse Infrared Background Experiment (DIRBE) on board the COBE satellite is the first space experiment designed to conduct a systematic search for the CIB in the 1.25 to 240 micron region.
The detection of the CIB is the most challenging of the three experiments on the COBE satellite. Its signal is hidden behind a veil of infrared emission from interplanetary dust, and from galactic stellar and dust emission. Peeling off these layers of foreground emissions, while leaving the cosmic signal unscathed is a formidable task.
In this talk I will describe the efforts of the DIRBE team to unveil the CIB. Additional clues to the energy density of the CIB are provided from the observations of TeV gamma rays from Markarian 421; I will describe our analysis of its spectrum and the resulting limits we derived on the CIB intensity. Finally, I will describe the theoretical efforts underway for modeling the IR emission from evolving galaxies, in order to estimate their contribution to the CIB.