"Laikini Gpa/hfp" radiošaltiniai

For investigation of the nature of GPS/HFP ('gigahertz peaked-spectrum / high-frequency peakers', possible young developing radio sources) it is important to construct robust, representative flux-density-limited samples. To look for spectra of the GPS/HFP type, we have used our RATAN-600 instantaneous broad-band 1-22 GHz spectra measurements of about 2000 compact extragalactic radio sources done in 1997-2003. We have found that some objects from published GPS/HFP samples change their spectra in time becoming non-GPS/HFP sources. We call such objects "temporary GPS/HFP" and suggest to use them cautiously. GPS/HFP-like type of spectrum can often be produced by an AGN during early stages of strong radio flares. and usually such a spectrum evolves to a flat one. A GPS-type spectrum could also be observed during a quiescent state of a relativistic jet when emission of an extended, slowly variable component of the source dominates. Some new GPS candidates are also found