VLBA observations of a sample of low-power compact symmetric objects
Compact symmetric objects (CSOs) are intrinsically compact extragalactic radio sources that are thought to be the progenitors of classical radio galaxies. To date, evolutionary models have mainly focused on the formation and growth of high-power radio sources, leaving unanswered many questions related to low-power objects, whose relativistic jets are likely more prone to instabilities. We present a new sample of candidate low-power CSOs selected from the Faint Images of the Radio Sky at Twenty-cm (FIRST) survey. The main selection criteria are (i) a parsec-scale double radio morphology from archival Very Long Baseline Array (VLBA) images and (ii) a VLBA total flux density consistent with that from the FIRST survey, which rules out the presence of significant radio emission extending beyond the parsec scale. The final sample consists of 60 sources with radio luminosities between 10 24 and 10 27 W Hz −1 at 1.4 GHz and projected linear sizes between 45 and 430 pc, which fill a region in the radio power-size plane that is currently underpopulated. We carried out VLBA observations at 4.98 GHz of a sub-sample of 20 sources among the brighest candidate CSOs with the aim of confirming their classification. We classify 12 sources as CSOs on the basis of their radio structure and spectral index distribution. In two out of the four CSOs with core identification, the asymmetry in the flux density of the outer components is in agreement with light travel time effects, and there is no evidence of jet-cloud interaction. If we assume a simplistic parametric model, most of the sources in the total sample have a jet power of ∼10 44 −10 45 erg s −1 , making their evolutionary paths sensitive to the individual conditions of the jet and its environment.
Authors
- D. Dallacasa (ORCID: https://orcid.org/0000-0003-1246-6492)
- M. Orienti (ORCID: https://orcid.org/0000-0003-4470-7094)
- Giulia Migliori (ORCID: https://orcid.org/0000-0003-0216-8053)
- P. Rossi (ORCID: https://orcid.org/0000-0002-0840-4726)
- F. D'Ammando
- G. Bodo (ORCID: https://orcid.org/0000-0002-9265-4081)
Publication Details
- Journal
- Astronomy and Astrophysics
- Published
- 2025-05-06
- DOI
- https://doi.org/10.1051/0004-6361/202553798
- Citations
- 1
- Primary Topic
- Astronomy and Astrophysical Research
- Type
- article
- Field-Weighted Citation Impact
- 1.19
Funders
- National Science Foundation
- Smithsonian Institution
- U.S. Department of Energy
- National Aeronautics and Space Administration
- Alfred P. Sloan Foundation
- Yale University
- Carnegie Institution of Washington
- Vanderbilt University
- University of Pennsylvania
- Ohio State University
- California Institute of Technology
- University of Chicago
- University of Utah
- University of Washington
- Johns Hopkins University
- Carnegie Mellon University
- University of Notre Dame
- University of Portsmouth
- New Mexico State University
- Carnegie Institution for Science
- National Energy Research Scientific Computing Center
- York University
- University College London
- University of Oxford
- University of Nottingham
- University of Sussex
- Deutsche Forschungsgemeinschaft
- Chinese Academy of Sciences
- Ministério da Ciência, Tecnologia e Inovação
- Financiadora de Estudos e Projetos
- Universidad Nacional Autónoma de México
- Max-Planck-Institut für Astrophysik
- Max-Planck-Institut für Astronomie
- Instituto de Astrofísica de Canarias
- University of Illinois at Urbana-Champaign
- Office of Science
- Jet Propulsion Laboratory
- University of California, Los Angeles
- University of Colorado Boulder
- Institut sur la Nutrition et les Aliments Fonctionnels
- Science and Technology Facilities Council
- Leibniz-Gemeinschaft
- Division of Astronomical Sciences
- High Energy Physics
- Integrated Electronics Engineering Center, Binghamton University
- Argonne National Laboratory
- Fermilab
- Lawrence Berkeley National Laboratory
- SLAC National Accelerator Laboratory