Hi Alba,
Currently, it's not possible to subscribe to internal alerts acting as application or provider. Maybe in the future this feature will be added, but it could has performance implications.
You can do it internally using the catalog token, but be carefull about it because this token shold be kept secure.
You could develop your own module, retrieve this kind of alerts, and do the logic you need (mail, e.g.).
Regards,
Sentilo Team.