A broadband study of FRB 20240114A with the Effelsberg 100-m radio telescope

Context. FRB 20240114A is a hyperactive repeating fast radio burst (FRB) source discovered by the CHIME/FRB Collaboration in January 2024. The source has been followed up by numerous radio telescopes, including MeerKAT, uGMRT, and FAST, and has been localized to a dwarf star-forming galaxy at a redshift of z ∼ 0.13 with a confirmed persistent radio source. Aims. We report observations of FRB 20240114A with the Effelsberg 100-m radio telescope using the Ultra BroadBand (UBB) receiver, covering 1.3–6.0 GHz. Over four epochs, we detected more than 700 bursts, providing an unprecedented broadband dataset for statistical analysis of this active repeater. Methods. We performed a comprehensive study of the bursts’ morphologies, occurrence rates, spectral and temporal widths, and waiting-time distributions across six sub-bands spanning the UBB frequency range. Results. The bursts exhibit four main spectral morphologies, including simple, complex, and frequency-drifting structures. No bursts were detected across the full 1.3–6 GHz band, confirming band-limited emission. Burst widths show modest frequency evolution, while fractional bandwidths remain roughly constant at ∼10%. Burst rates vary strongly with time and frequency, partly influenced by scintillation. The waiting-time distribution is bimodal, with largely independent bursts and short-timescale clustering on ∼10 ms, indicating a characteristic emission timescale. The source can switch emission frequencies by ≳GHz on seconds and by ∼700 MHz on millisecond timescales, implying a highly agile emission mechanism. Conclusions. Taken together, these results indicate that FRB 20240114A is powered by a dynamic emission mechanism capable of rapid spectral modulation. The short-timescale clustering, downward frequency drifts, and lack of separation between intra- and inter-burst intervals suggest a continuous burst behaviour arising from a common physical process. This emphasizes the importance of wideband, high-time-resolution observations to constrain emission models and reveals that even among active repeaters, individual sources can exhibit unique spectral-temporal signatures.