The effect of Cepheids exhibitting blending, bumps, eclipses and period changes on the Period-Luminosity relation
Abstract
The study of structural breaks (non-linearity) on the Period-Luminosity relation began more than seven decades ago. Since then, some studies has found breaks in the Period-Luminosity relation. The objective in this work is to look for possible statistical causes of these breaks by means of robust techniques, instead of Ordinary Least Squares, to fit linear regression to OGLE-II and OGLE-IV data. These robust methods allow us to deal with influential points whose presence is a violation to the Ordinary Least Squares assumptions. In fact, fitting the models using M and MM-regressions, we do not find evidence to say that Period-Luminosity relation is non-linear in the LMC. Therefore, light curves of Cepheids suggesting blending, bumps, eclipses and period changes do not have an effect on the Period-Luminosity relation in this galaxy. On the contrary, for SMC, maybe, because of the geometry of the galaxy, there is a possible effect these stars and adequate models could not be found.
- Publication:
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Revista Mexicana de Astronomia y Astrofisica Conference Series
- Pub Date:
- July 2017
- Bibcode:
- 2017RMxAC..49..165M