  We present results of our study of correlated radio and X-ray emission in two
black hole candidates and Galactic microquasars GRS 1915+105 and Cygnus X-1 in
their steady long term hard states, along with Cygnus X-3 (using data obtained
from RXTE-ASM, CGRO-BATSE and GBI). We detect a pivotal behavior in the X-ray
spectrum of GRS 1915+105, correlated to the radio emission. Similar to the
results obtained for Cygnus X-3, the flux of X-rays softer than the pivoting
point correlates with the radio emission, while the corresponding harder X-ray
flux anti-correlates with both the radio and the softer X-ray emission, in this
state. We examine all the previously reported correlations of X-ray properties
with the radio emission in Galactic microquasars and argue that these are
consistent with a general picture where a spectral pivoting is a common feature
in these sources with the shape of the spectrum determining the flux of radio
emission, during the hard states. We also detect a general monotonic increase
in the radio emission of these sources with the soft X-ray emission spanning
about 5 orders of magnitude. We qualitatively explain these findings with a Two
Component Advective Flow model where the location of a boundary layer between
the thin disk and the Comptonizing region determines the spectral shape and
also the amount of outflow.
