Spectra of N₂H⁺ (3–2) toward the whole sample of pre-stellar core candidates in Table A.1. From top to bottom and then from left to right, the spectra are ordered in integrated intensity, with CRA 047 being the strongest. The spectra have also been displaced in intensity by multiples of 2 K and centered at 0 LSR velocity, for a comparison. Note that the spectra of the first ten objects have been divided by factors of between 6 and 2 (see labels) for clarity. Asterisks next to the names indicate the association with a YSO.