Search and analysis of giant radio galaxies with associated nuclei (SAGAN). V. Study of giant double-double radio galaxies from LoTSS DR2
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1.
National Centre for Nuclear Research
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2.
Instituto de Astrofísica de Canarias
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3.
University of La Laguna
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4.
Inter-University Centre for Astronomy and Astrophysics
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5.
California Institute of Technology
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6.
Leiden University
Abstract
To test the hypothesis that megaparsec-scale giant radio galaxies (GRGs) experience multiple epochs of recurrent activity leading to their giant sizes and to understand the nature of double-double radio galaxies (DDRGs), we have built the largest sample of giant DDRGs from the LOFAR Two Metre Sky Survey (LoTSS) data release 2. This sample comprises 111 sources, including 76 newly identified DDRGs, with redshifts ranging from 0.06 to 1.6 and projected sizes between 0.7 Mpc and 3.3 Mpc. We conducted a detailed analysis to characterise their properties, including arm-length ratios, flux density ratios of pairs of lobes, and misalignment angles. These measurements allow us to study the symmetry parameters, which are influenced by the immediate and large-scale environments of DDRGs. Our study shows that based on the observed asymmetries of the inner lobes, the cocoons in which the inner lobes of DDRGs grow are often (approximately about 26%) asymmetrically contaminated with surrounding material from the external medium. Our analysis also reveals highly misaligned DDRGs, which could be due to environmental factors and/or changes in the supermassive black hole jet ejection axes. By studying the misalignment angles, we assess the stability of the jets in these systems in relation to their environment. For the first time, we systematically characterised the large-scale environments of DDRGs, identifying their association with dense galaxy clusters and revealing the influence of 'cluster weather' on their morphologies. We have discovered a DDRG in a distant galaxy cluster at z ∼ 1.4. Our findings empirically confirm that dynamic cluster environments can induce significant misalignment in DDRGs, which aligns with previous simulation predictions and offers insights into how cluster weather shapes their morphology. Additionally, we have identified two gigahertz peaked-spectrum (GPS) candidates in the unresolved cores of the DDRGs, as well as one triple-double candidate, which, if confirmed, would be only the fifth known case. Overall, this study enhances our understanding of the life cycle of radio AGNs and underscores the critical role of the environment in shaping the properties and evolution of giant DDRGs.
Copyright and License
© The Authors 2025.
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Acknowledgement
We thank the anonymous reviewer for several comments and suggestions which have helped improve the manuscript. PD acknowledges support from the Spanish Ministry of Science and Innovation under the grant – “PARSEC: Multiwavelength investigations of the central parsec of galaxies” (PID2020-114092GB-I00). LOFAR data products were provided by the LOFAR Surveys Key Science Project (LSKSP; https://lofar-surveys.org/) and were derived from observations with the International LOFAR Telescope (ILT). LOFAR (van Haarlem et al. 2013) is the Low Frequency Array designed and constructed by ASTRON. It has observing, data processing, and data storage facilities in several countries, which are owned by various parties (each with their own funding sources), and which are collectively operated by the ILT foundation under a joint scientific policy. The efforts of the LSKSP have benefited from funding from the European Research Council, NOVA, NWO, CNRS-INSU, the SURF Co-operative, the UK Science and Technology Funding Council and the Jülich Supercomputing Centre. We acknowledge the use of the DESI Legacy Imaging Surveys (https://www.legacysurvey.org/acknowledgment/). This research has made use of the CIRADA cutout service at cutouts.cirada.ca, operated by the Canadian Initiative for Radio Astronomy Data Analysis (CIRADA). CIRADA is funded by a grant from the Canada Foundation for Innovation 2017 Innovation Fund (Project 35999), as well as by the Provinces of Ontario, British Columbia, Alberta, Manitoba and Quebec, in collaboration with the National Research Council of Canada, the US National Radio Astronomy Observatory and Australia’s Commonwealth Scientific and Industrial Research Organisation. This research has made use of the NASA IPAC Extragalactic Database (NED), which is funded by the National Aeronautics and Space Administration and operated by the California Institute of Technology. This research has made use of the VizieR catalogue tool, CDS, Strasbourg, France (Ochsenbein et al. 2000). We acknowledge that this work has made use of ASTROPY (Astropy Collaboration 2013), APLPY (Robitaille & Bressert 2012), and TOPCAT (Taylor 2005).
Software References
This research has made use of the VizieR catalogue tool, CDS, Strasbourg, France (Ochsenbein et al. 2000). We acknowledge that this work has made use of ASTROPY (Astropy Collaboration 2013), APLPY (Robitaille & Bressert 2012), and TOPCAT (Taylor 2005).
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Additional details
Related works
- Is new version of
- Discussion Paper: arXiv:2408.13607 (arXiv)
Funding
- Ministerio de Ciencia, Innovación y Universidades
- PID2020-114092GB-I00
Dates
- Accepted
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2025-02-27
- Available
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2025-04-08Published online