Academic staff are covered by the agreement on official travel and, therefore, you are entitled to reimbursement of any additional expenses in connection with a research stay abroad. The AU Finance, Travel Expense Account Unit has made a brief overview of expenses that may be covered by the university, as well as those not covered by the university, when going on a research stay abroad.
See the AU page about taxation of travel expenses for official trips - more than 28 days
As a PhD student employed at AU, you are not entitled to reimbursement of any additional expenditure in connection with a study abroad period, as PhDs are not covered by the agreement on official travel. However, your faculty/department/centre may decide to use one or the other of the below options:
Read about coverage of PhD expenses on the AU page Postings and change of research environment abroad
In connection with the posting of academic staff, the employing unit (faculty/department/school/centre) can decide to pay, to a limited degree, some expenses related to accompanying family.
PhD students are, in this connection, not considered academic staff and therefore may not have expenses for the accompanying family paid by the university.
Read more about expenses for accompanying family on the AU page Postings and change of research environment abroad