Dating COINS: Kinematic Ages for Compact Symmetric Objects

We present multi-epoch VLBA observations of Compact Symmetric Objects (CSOs)from the COINS sample (CSOs Observed In the Northern Sky). These observationsallow us to make estimates of, or place limits on, the kinematic ages for thosesources with well-identified hot spots. This study significantly increases thenumber of CSOs with well-determined ages or limits. The age distribution isfound to be sharply peaked under 500 years, suggesting that many CSOs dieyoung, or are episodic in nature, and very few survive to evolve into FR IIsources like Cygnus A. Jet components are found to have higher velocities thanhot spots which is consistent with their movement down cleared channels. Wealso report on the first detections of significant polarization in two CSOs,J0000+4054 (2.1%) and J1826+1831 (8.8%). In both cases the polarized emissionis found in jet components on the stronger side of the center of activity.Comment: 34 pages including 7 figures, Accepted to ApJ on Dec 7, 200