Cannot implicitly convert type IEnumerable to IQueryable with Entities

I am completely new to Entities (I've taken over another persons project) and therefore I am prolly missing some key facts but I'll try and explain my problem:

I have applicants who has a table with their information like first name etc. And I also have a table with the ASP.NET Users. The tables are linked by the user_id.

I am trying to make the login name a selectable listitem in a dropdown but in order to do so I need to join the two tables. I have written the following code:

var container = new ModelContainer();
var manager = new ApplicantDBManager();

IEnumerable<Business.Entities.EF.Applicant> applicantQuery;

if (txtSearch.Text.Equals(string.Empty))
{
    applicantQuery = container.Applicants;
}
else
{
    var ids = manager.ApplicantSearchForIDs(ddlSearch.SelectedValue, txtSearch.Text, chkIncludeInactive.Checked);

    applicantQuery = (from a in container.Applicants
                      join u in container.Users on a.user_id equals u.user_id
                      where ids.Contains(a.user_id)
                      select new
                      {
                          user_id = a.user_id,
                          first_name = a.first_name,
                          last_name = a.last_name,
                          login_name = u.login_name,
                          date_of_birth = a.date_of_birth,
                          kot_cpr = a.kot_cpr,
                          address = a.address,
                          email = a.email,
                          telephone_number = a.telephone_number,
                          citizenship = a.citizenship
                      });
}

I am getting an error like "Cannot implicitly convert type System.Linq.Iqueryable to System.Collections.Generic.IEnumerable" and it seems not to matter how I try and fix it (I've tried adding .ToList().AsQueryable(), First() and such with no luck). I think it has something to do with the Applicant entity?