Long-term meter wavelength variability study of Blazar J1415+1320 using
  the Ooty Radio Telescope
  J1415+1320 is a well-studied blazar that exhibits strong flux density
variability at a wide range of radio frequencies (2.4 $-$ 230~GHz). In this
letter, we present a variability study of this source at 327~MHz using the data
obtained with the Ooty Radio Telescope taken during the period 1989 to 2018.
Two significant flares are detected at epochs 2007.6 and 2008.6. These flares
are also seen in the publicly available 15 and 37~GHz light curves but with a
lead time of a few months. The fractional changes in the flux densities are
larger at frequencies $>$ 15~GHz compared to those at 327~MHz and the spectral
indices of the increased flux densities are flatter compared to the quiescent
spectrum during these flares. These observed features are consistent with a
model of uniformly expanding cloud of relativistic electrons or shock-in-jet
model. Our 327~MHz dataset also overlaps with a rare form of variability $-$
symmetric achromatic variability (SAV) $-$ seen at higher frequencies ($>$
15~GHz) toward the source. SAV is possibly due to gravitational milli-lensing
of the core emission by an intervening massive object and is expected to be
detected at all frequencies \cite{Vedantham2017}. No variability in association
with the SAV events is seen in the 327~MHz dataset; however, if SAV is due to
the lensing of core emission alone then the expected variability is less than
3$\sigma$ uncertainty in our measurements.
