  The low temperature scanning tunneling microscopy spectra in the underdoped
regime is analyzed from the perspective of coexisting $d$-density wave and
d-wave superconducting states. The calculations are carried out in the presence
of a low concentration of unitary impurities and within the framework of the
fully self-consistent Bogoliubov-de Gennes theory, which allows local
modulations of the magnitude of the order parameters in response to the
impurities. Our theory captures the essential aspects of the experiments in the
underdoped BSCCO at very low temperatures.
