Stellar mergers as the origin of magnetic massive stars.

About ten per cent of 'massive' stars (those of more than 1.5 solar masses) have strong, large-scale surface magnetic fields. It has been suggested that merging of main-sequence and pre-main-sequence stars could produce such strong fields, and the predicted fraction of merged massive stars is also about ten per cent.

Response to Comment on "An excess of massive stars in the local 30 Doradus starburst".

Farr and Mandel reanalyze our data, finding initial mass function slopes for high-mass stars in 30 Doradus that agree with our results. However, their reanalysis appears to underpredict the observed number of massive stars. Their technique results in more precise slopes than in our work, strengthening our conclusion that there is an excess of massive stars (>30 solar masses) in 30 Doradus.