  Nodal-point and Nodal-line structures in the dispersion of electron energy
bands are characterized by their high degeneracy in certain corners or lines in
the Brillouin zone (BZ). These nodal structures can also exist in the
dispersion of itinerant electrons in magnetically ordered materials whose
symmetry groups are anti-unitary groups called the magnetic space groups. In
the present work, we provide a complete list of magnetic space groups which can
host symmetry-protected nodal-point/line band structure, where the degeneracies
at the nodal points/lines are guaranteed by irreducible projective
representations (IPReps) of the little co-groups. Our discussion is restricted
to the magnetic space groups whose magnetic point group contain the space-time
inversion operation $\tilde T=\mathcal IT$, the combined operation of spacial
inversion $\mathcal I$ and time reversal $T$, such that the energy bands are
doubly-degenerate at arbitrary points in the BZ. For these magnetic point
groups we provide the invariants to label the classes of projective Reps, and
for each class we calculate all of the inequivalent IPReps. From the results we
select out all the groups and the corresponding representation classes which
support high-dimensional ($d\geq$4) IPReps. We then list the magnetic space
groups and their high symmetry points/lines whose little co-groups have
high-dimensional ($d\geq$4) IPReps with the corresponding factor systems.
Examples of candidate materials are discussed.
