asp.net mvc - RedirectToAction after Owin ExternalLogin adds # hash to the url -

after logging in using google auth on site , redirecting home/index hash # added url.

now noticed stackoverflow.com has similar thing, after logged in using facebook got redirected to: http://stackoverflow.com/#_=_

my controller code quite standard:

[allowanonymous] public async task<actionresult> externallogincallback(string returnurl) {     var logininfo = await httpcontext.getowincontext().authentication.getexternallogininfoasync();     if (logininfo == null)     {         return content("failed");     }     // removed rest of code identify problem      return redirecttoaction("index", "home"); } 

anybody knows why hash # appears in url, , can rid off ?