ows_editior missing in Metadata Property Mappings in SharePoint 2010

I'm trying to map a Managed Property to the Modified By field in document library's. I can see that the internal name of the field is E开发者_如何学JAVAditor. But I can't find ows_editor in crawled Properties.

Is there a way of adding it to the crawled properties, and how?

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Upload any document to the library where the mapping column exist. Then perform a full crawl and you will be able to see the required crawled properties.