PPAK wide-field Integral Field Spectroscopy of NGC 628:

II. Emission line abundance analysis

The data release includes:

(i) The HII region catalogue of NGC628, including the number identification (ID); the Right Ascension and Declination of the central reference point of each HII region (in sexagesimal and degree units), for the 2000 equinox; the offsets of each region, in arcsec, with respect to the reference central point of the IFS mosaic, in the standard configuration with north-east positive; a “Method” column corresponding to the extraction method employed during the selection of the HII region: A stands for an aperture extraction (i.e. a circular aperture of given size in arcsec), and M stands for manual extraction (i.e. fibres selected by hand); an “Aperture” value standing for the real (aperture) or equivalent (manual) extraction aperture diameter in arcsec; a “Size” column corresponding to the physical size of the HII region in parsecs, at the assumed distance to the galaxy, and the total number of fibres from which the spectra of the HII regions were extracted.

(ii) Reddening-corrected emission line intensities for the HII region catalogue, normalised to Hβ (with 1σ errors), including: [OII] λ3727, Hγ λ4340, Hβ, [OIII] λ4959, [OIII] λ5007, He I λ5876, [NII] λ6548, Hα, [NII] λ6584, [SII] λ6717.

(iii) Derived properties of the HII region catalogue, including: A_V, the logarithmic extinction coefficient c(Hβ) derived from the Balmer decrement, Hβ flux in units 10⁻¹⁶ erg s⁻¹ cm⁻², the Hα luminosity, the ionization parameter log u, the R23 value, and the 12 + log(O/H) values for the four strong-line metallicity calibrators (KK04, O3N2, ff–Te, P07) as described in the paper.