2003/09/12 by S. Tinti, Tinti, S., D. Dallacasa +8
Engineering · Physics and Astronomy · Social Sciences · #Astrophysics (astro-ph) #Child Development and Digital Technology #Energy Harvesting in Wireless Networks #FOS: Physical sciences #Gyrotron and Vacuum Electronics Research #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0309354
5 pages, 3 figures. To appear in ASP Conference Series: "Future Directions in High Resolution Astronomy: A Celebration of the 10th Anniversary of the VLBA", June 8 - 12, 2003, Socorro, New Mexico, USA
arxiv created 2003/09/12 · openalex publication_date 2003/09/12 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present the results of second epoch simultaneous multifrequency observations of 45 sources out of the 55 in the sample of High Frequency Peakers (HFP) by Dallacasa et al. (2000). Seven of the stellar sources (i.e. 16% of the total number of sources and 26% of the stellar fraction) no longer show a convex spectrum and are thus likely to be flat spectrum quasars in an outburst phase during the first epoch of observations. The rest frame peak frequency distribution of HFP quasars extends up to ~45 GHz while that of HFP galaxies is confined to ≤ 17 GHz. Imaging at 1.465 GHz and 1.665 GHz has revealed extended emission for 31% of sources, a substantially larger fraction than found for GPS sources (~10%). In the case of HFP quasars, but not of HFP galaxies, extended emission is associated with strong variability, consistent with a core-jet structure.