As XYZ files only have atom name information, the atoms are all assigned to the same residue and segment.
The default timestep in MDAnalysis is 1 ps. A different timestep can be defined by passing in the dt argument to Universe.
Definiton used by the
the VMD xyzplugin from whence the definition was taken):
[ comment line ] !! NOT IMPLEMENTED !! DO NOT INCLUDE [ N ] # of atoms, required by this xyz reader plugin line 1 [ molecule name ] name of molecule (can be blank) line 2 atom1 x y z [optional data] atom name followed by xyz coords line 3 atom2 x y z [ ... ] and (optionally) other data. ... atomN x y z [ ... ] line N+2
comment lines not implemented (do not include them)
molecule name: the line is required but the content is ignored at the moment
optional data (after the coordinates) are presently ignored