Searching for Oscillations in the Primordial Power Spectrum: Constraints
  from Planck (Paper II)
  We apply our recently developed code to search for resonance features in the
Planck CMB temperature data. We search both for log spaced oscillations or
linear spaced oscillations and compare our findings with results of our WMAP9
analysis and the Planck team analysis. While there are hints of log spaced
resonant features present in the WMAP9 data, the significance of these features
weaken with more data. With more accurate small scale measurements, we also
find that the best fit frequency has shifted and the amplitude has been
reduced. We confirm the presence of a several low frequency peaks, earlier
identified by the Planck team, but with a better improvement of fit (delta
chi^2 ~ 12). We further investigate this improvement by allowing the lensing
potential to vary as well, showing mild correlation between the amplitude of
the oscillations and the lensing amplitude. We find that the improvement of the
fit increases even more (delta chi^2 ~ 14) for the low frequencies that modify
the spectrum in a way that mimics the lensing effect. Since these features were
not present in the WMAP data, they are primarily due to better measurements of
Planck at small angular scales. For linear spaced oscillations we find a
maximum delta chi^2 ~ 13 scanning two orders of magnitude in frequency space,
and the biggest improvements are at extremely high frequencies. We recover a
best fit frequency very close to the one found in WMAP9, which confirms that
the fit improvement is driven by low l. Further comparisons with WMAP9 show
Planck contains many more features, both for linear and log space oscillations,
but with a smaller improvement of fit. We discuss the improvement as a function
of the number of modes and study the effect of the 217 GHz map, which appears
to drive most of the improvement for log spaced oscillations. We conclude that
none of the detected features are statistically significant.
