Possible solutions for the REB modulation fitting (see Sect. 4.2). Each grey open circle (and its correspondent error bars) represents a possible solution for the REB modulations whose χ² value is statistically valid as compared to the minimum χ² obtained with the genetic algorithm. We have marked the adopted model in black, being the one that presents the least relative errors. The red symbol corresponds to the most repeated value (and standard deviation deviation) for each parameter in the whole set of statistically acceptable solutions.