The Study of Nebular Emission on Nearby Spiral Galaxies in the IFU Era
Figure 3
(a) Radial abundance gradient derived for NGC 628 based on the PINGS HII region catalogue (green symbols), and HII regions from the literature (black symbols) using the O3N2 calibrator. The horizontal grey lines correspond to the abundance derived using the integrated spectrum as reported in Paper I. The top -axis values correspond to the projected radii in arcsec for the radial average data. Note the flattening of the gradient for innermost regions of the galaxy and for radii >, that is, a multimodality of the abundance gradient. (b) 2D distribution of the oxygen abundance derived from the IFS H II regions catalogue of NGC 628 (plus selected HII regions from the literature), for the KK04 (top-left) metallicity calibrators. The shape and colours of the symbols correspond to the difference [12 + log(O/H)] ≡ log (O/H) between the abundance obtained on each HII region with respect to the characteristic abundance 12 + of the same calibrator, grouped into bins of 0.0, ±0.1, 0.2 dex (e.g., +0.1 dex = 0.05 ≤log (O/H) < 0.15). The large symbol in red colour stands for the location of the HII region with the maximum amount of 12 + log(O/H) measured for that calibrator. The grey thick lines define the operational spiral arms of the galaxy. The dotted circle corresponds to the size of the optical radius . Figure adapted from Rosales-Ortega et al. [30].
