rrow-Angle Tail, HYMORE, and Double-Doubles that consist of multiple components.
While many of the groups have a component identifiable as a 'core' and are thus in the FIRST catalog, for a significant fraction there is no identifiable radio component at the expected core position.
Other related publications:
Proctor, D. D. 2002, J. Electron. Imaging, 12, 398 (2003JEI....12..398P) Low Resolution Pattern Recognition - Sorting Triples in the FIRST Database.
Use of Morphological Annotations for Groups in the FIRST Database.
Proctor, D. D. 2006, Astrophys. J., Suppl. Ser., 165, 95 (2006ApJS..165...95P) Comparing Pattern Recognition Feature Sets for Sorting Triples in the FIRST Database.
See also FIRST. Ref:=2011ApJS..194...31P byPROCTOR D.D. Astrophys. J., Suppl. Ser., 194, 31 (2011) Morphological annotations for groups in the FIRST database. oTables 1-15: <FCG JHHMMSS.s+DDMMSS> N=1932. Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory =E=Catalogue in electronic form as J/ApJS/194/31
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