Curve which runs through, for instance, all maxima of a family of curves

[ESA]

How do you name a curve which runs through, for instance, all maxima of a family of curves?

Hello, I'm from Germany and I must know the name of that curve in English.
Already surched a lot but didn't find a correct translation.

I mean the red curve:
http://mathenexus.zum.de/html/abschlusspruefungen/2008/12NT/m08_12nta2_lsg_images/IMG7716.PNG

Thanks!