2024A&A...683A.179B

We present the first deep (72 h of observations) radio image of the Euclid Deep Field North (EDFN) obtained with the LOw-Frequency ARray (LOFAR) High Band Antenna (HBA) at 144 MHz. The EDFN is the latest addition to the LOFAR Two-Metre Sky Survey (LoTSS) Deep Fields, and these observations represent the first data release for this field. The observations produced a 6″ resolution image with a central rms noise of 32 μJy beam^–1. A catalogue of ∼23 000 radio sources above a signal-to-noise ratio threshold of five is extracted from the inner circular 10 deg² region. We discuss the data analysis, and we provide a detailed description of how we derived the catalogue of radio sources, the issues related to direction-dependent calibration, and their effects on the final products. Finally, we derive the radio source counts at 144 MHz in the EDFN using catalogues of mock radio sources to derive the completeness correction factors. The source counts in the EDFN are consistent with those obtained from the first data release of the other LoTSS Deep Fields (ELAIS-N1, Lockman Hole and Bootes), despite the different method adopted to construct the final catalogue and to assess its completeness.