2012 Spring Physics Colloquium Series: Dr. Ohad Shemmer

DateFebruary 15, 2012
Time4:00 - 5:00 pm
LocationBaylor Sciences Building, Room E.125
Ohad Shemmer, Ph.D.

Assistant Professor, University of North Texas

Solving the Mystery of Weak Emission Line
Quasars at High Redshift

Since strong and broad emission lines are a hallmark of quasar spectra, the recent discovery of luminous, high-redshift quasars with strong blue continua but extremely weak or undetectable emission lines is puzzling. I will present a step-by-step overview of multiwavelength observations that provided insights into the nature of these remarkable sources. In particular, I will show that the weakness of their emission lines is unlikely to be due to line absorption, dust obscuration, gravitational lensing or microlensing effects, or relativistic beaming. Finally, I will describe an observational and theoretical effort required to distinguish between two competing scenarios for the weakness of the emission lines in these sources. The results of this study will likely shed light not only on the nature of this rare class of quasars but also on emission-line formation in all active galactic nuclei.

For More information contact: Dr. Anzhong Wang x 2276

PublisherDepartment of Physics
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