Year: 2026
Type: preprint
Abstract: We present the first deep, targeted LOFAR 144 MHz source catalogue of the COSMOS field, together with the first 144 MHz source counts in this field. The data comprise 48 h of observations. Over the 2.6 sq. deg. region adopted for the catalogue analysis, the final Dutch-array image reaches a median rms sensitivity of ~100 uJy/beam at an angular resolution of 15" x 6". The resulting catalogue contains 1984 radio sources; a peak S/N >= 5 selection is adopted for the resolved/unresolved classification and source-count analysis. We characterised the catalogue using Monte Carlo source-injection and recovery simulations, including dedicated simulations of extended sources, to quantify completeness, flux-density redistribution, and morphology-dependent source-recovery effects. The catalogue reaches 90% completeness at 1.48 mJy. The resulting Euclidean-normalised differential source counts are measured down to ~0.4 mJy and show good agreement with LoTSS DR3 144 MHz source counts and with the VLA-COSMOS 3 GHz counts scaled to 144 MHz, with ~5% of catalogue sources having multiple 3 GHz counterparts within a beam-matched search region. Comparison with the VLA-COSMOS 3 GHz catalogue shows good astrometric agreement, with median offsets of Delta_RA = 0.35" (+0.03"/-0.05") and Delta_Dec = -0.83" (+0.02"/-0.03"), approximately 6% of the corresponding synthesised-beam dimensions, and no significant radial dependence across the field. The resulting catalogue provides a low-frequency view of COSMOS and a reference dataset for future deeper LOFAR observations and multiwavelength studies of this extensively characterised extragalactic field.
Source: arXiv (Cornell University)
Institutions: Leiden University, Leiden Observatory, Netherlands Institute for Radio Astronomy, University of Hertfordshire, University of Thessaly, Durham University, Royal Observatory, University of Edinburgh, École Polytechnique Fédérale de Lausanne, University of Zagreb, Osservatorio di Astrofisica e Scienza dello Spazio, National Institute for Astrophysics, University of Helsinki, Aalto University, Chinese Academy of Sciences, Yunnan Observatories, Universidad Diego Portales, California Institute of Technology, Infrared Processing and Analysis Center, University of Tarapacá, Rochester Institute of Technology, University of California, Santa Barbara, Université Paris-Saclay, Institut d'Astrophysique Spatiale, European Southern Observatory
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: UK Research and Innovation, Department of Science and Innovation, South Africa, National Research Foundation, University of Pretoria, University of the Western Cape, University of Cape Town, Agencia Nacional de Investigación y Desarrollo, Science and Technology Facilities Council, European Regional Development Fund
Awards: An unbiased and resolved view of cosmic star formation, G1424166960, G1717035117, G2421315707, G2547403317, G2946970296, G3148402578, G3167403879, G4133407093, A COMPREHENSIVE VIEW OF THE CONNECTION BETWEEN SUPERMASSIVE BLACK HOLE GROWTH AND MAJOR GALAXY MERGERS, G4771127440, MILLENIUM NUCLEUS FOR GALAXIES, G5191139945, G6116975293, Unveiling the physics of radio AGN feedback with LOFAR, G7303268391, LOFAR-UK Request for Continued Funding, 2021-2024, and LOFAR2.0 Upgrade, SPECTRO-TEMPORAL STUDIES OF AGN POPULATIONS, ORCHIDS: ORIGIN OF THE [CII] HALOS IN DISTANT SYSTEMS, CENTRO DE ASTROFISICA Y TECNOLOGIAS AFINES (CATA), G878560454
OpenAlex ID: W7221826103