A spatially resolved study of ionized regions in galaxies at different ...

20 2 • The star formation history of NGC 5471
Figure 2.5: Plot of the eleven polygons, limiting the different areas where the integrated magnitudes
are computed. The numbers belong to our own definition while the A, B, C, D and E letters are the
knots identified by Skillman (1985). The hypernova is located in knot 6.
cm −2 s −1 Å −1 (14.24 ± 0.05 AB magnitudes).
In order to use these values in the analysis, we need to transform AB magnitudes to the
VEGAMAG system. The transformation formula is (Maíz-Apellániz, 2007):
AB p = (m p − ZP p ) + AB p (V ega) (2.1)
where AB p is the magnitude of the object in the AB system and filter passband p, m p the
magnitude of the object in filter p using Vega as reference spectral energy distribution (SED),
ZP p is the zero point of the p filter in the Vega system and AB p (Vega) is the AB magnitude
of Vega in filter p. This magnitude is given by: