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It has been more than two decades since it was recognized that the general
phenomenon of higher gas temperature in the inner few hundred pcs
by comparison with local clouds in the disk of the Galaxy. This is one
of the least understood characteristics of giant molecular clouds having
a much higher gas temperature than dust temperature in the inner few
degrees of the Galactic center. We propose that the enhanced cosmic ray
electrons in the nuclear disk, as evidenced recently by a number of studies,
are responsible for heating directly the gas clouds and elevate the
temperature of molecular gas. The higher ionization fraction and higher
thermal energy due to the impact of these electrons have important implications
in slowing down star formation and reducing the MHD waves
damping which results a high velocity dispersion of molecular gas in the
nuclear disk. To support the role of cosmic rays in star forming regions,
we show evidence of nonthermal radio continuum emission associated
with the Sgr B2 cloud based on low–frequency GMRT and VLA observations.
In addition, the correlation of methanal maser distribution
against IRAC and MIPS images of Galactic nuclear disk will be presented.
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