Circular Polarization Survey Results of the CLASS Telescope*

There are several predictions for the circularly polarized (Stokes V) emission of the Cosmic Microwave Background (CMB), but few experimental constraints have been made. The Cosmology Large Angular Scale Surveyor (CLASS) is conducting a multi-frequency CMB polarization survey covering 75\% of the sky. Though its primary goal is measuring CMB linear polarization, CLASS also has explicit sensitivity to circular polarization due to its Variable-delay Polarization Modulator (VPM) technology. With this sensitivity, we are able to present new constraints on circular polarization.