The SPLASH and Chandra COSMOS Legacy Survey: the Cross Power Between
  Near-Infrared and X-Ray Background Fluctuations
  We study the source-subtracted near-infrared and X-ray background
fluctuations of the COSMOS field using data from the Spitzer SPLASH program
($\sim$1272 hours) and Chandra COSMOS Legacy Survey (4.6 Ms). The new auto
power spectra of the cosmic infrared and X-ray background fluctuations reach
maximum angular scales of $\sim$ 3000$''$ and $\sim$ 5000$''$, respectively. We
measure the cross power spectra between each infrared and X-ray band and
calculate the mean power above 20$''$. We find that the soft X-ray band is
correlated with 3.6 and 4.5$\mu$m at $\sim$ 4 $\sigma$ significance level. The
significance between hard X-ray and the 3.6$\mu$m (4.5$\mu$m) band is $\sim$2.2
$\sigma$ ($\sim$3.8$\sigma$). The combined infrared (3.6 + 4.5$\mu$m) data are
correlated with the X-ray data in soft ([0.5-2] keV), hard ([2-7] keV) and
broad ([0.5-7] keV) bands at $\sim$5.6$\sigma$, $\sim$4.4$\sigma$ and
$\sim$6.6$\sigma$ level, respectively. We compare the new measurements with
existing models for the contributions from known populations at $z$$<$7, which
are not subtracted. The model predictions are consistent with the measurements
but we cannot rule out contributions from other components, such as Direct
Collapse Black Holes (DCBH). However, the stacked cross-power spectra,
combining other available data, show excess fluctuations about an order of
magnitude on average at $\sim$4$\sigma$ confidence at scales within
$\sim$300$''$. By studying the X-ray SED of the cross-power signal, assuming no
significant variation from the infrared, we find that its shape is consistent
with DCBHs.
