L. Bondonneau, J.-M. Grießmeier, G. Theureau, I. Cognard, F. Jankowski, V. Kondratiev, I. Kravtsov, J. Pétri, A. Possenti, O. Ulyanov, V. Zakharenko, M. Brionne, B. Cecconi, S. Corbel, J. N. Girard, O. Konovalenko, P. Tokarsky, P. Zarka
The radio frequency range below 100 MHz has been unexplored until recently for extended pulsar population studies. We present the first low-frequency pulsar census of the northern sky with the NenuFAR radio telescope (10--85 MHz), performed during its commissioning and early science phase in 2019--2021. Our programme was conceived as the first stepping stone of a future pulsar key science project, aimed at preparing for targeted studies on pulsars of peculiar interest (mode switching, drifting subpulses, and polarised emission), exploring pulsar spectra and pulse-shape evolution below the expected turn-over, and investigating dispersion and scattering due to the interstellar and heliospheric plasma. We observed all known pulsars observable from the Nançay Radio Observatory in France, i.e. with a declination above -20̧irc$ and dispersion measures (DMs) up to 100 At the time of the sample selection, 576 pulsars fulfilled these criteria in the ATNF pulsar catalogue. We complemented this sample with 69 additional LOTAAS/LOFAR pulsars, yielding 645 observed pulsars. We used the 56 mini-arrays available in the NenuFAR core (i.e. 1064 antennas), corresponding to $∼58% of the nominal collecting area. Targets were observed for between 25 and 180 minutes, depending on their elevation and nature (regular or millisecond pulsars). We detected 182 pulsars in the frequency range 10--85 MHz, 89 of which had never been seen before in this range. We detected 13 millisecond pulsars, ten of which are new detections below 100 MHz. We measured new DMs, scattering indices, duty cycles, and calibrated fluxes for all of them. The typical minimum detectable pulse was 1--2 mJy for MSPs and 5--10 mJy for the regular population. We release full-band phasograms for all targets, with frequency-resolved pulse profiles where the pulsar was bright enough.