  We searched the Chandra and XMM archives for observations of 900 green pea
galaxies to find AGN signatures. Green peas are low-mass galaxies with
prominent emission lines, similar in size and star formation rate to
high-redshift dwarf galaxies. Of the 29 observations found, 9 show X-ray
detections with $S/N>3$. The 2-10 keV X-ray luminosity for these 9 sources
exceeds $10^{40}~\mathrm{erg~s}^{-1}$, with 2 sources exceeding
$10^{41}~\mathrm{erg~s}^{-1}$, suggesting the presence of intermediate-mass
black holes (IMBH) or low-luminosity AGN (LLAGN) with BH masses between
$100-10^6M_\mathrm{\odot}$. All X-ray detected sources (plus 6 additional
sources) show He~II$\lambda4686$ emission and a broad component of the
H$\alpha$ emission line, indicating winds. The line widths of the broad
H$\alpha$ and He II$\lambda4686$ emitting gas clouds are weakly correlated
($R^{2}=0.15$), suggesting He II$\lambda4686$ emission is inconsistent with
winds from super-Eddington accretors. However, the ratio of X-ray luminosity to
star formation rate shows an anti-correlation with metallicity in 5 out of 9
X-ray detected sources, implying ultraluminous X-ray sources are key
contributors to the observed X-ray luminosity. This could be due to
super-Eddington accretors or IMBH. The X-ray emission is much higher than that
produced by Wolf-Rayet stars and supernovae-driven winds. Thus, the X-ray
luminosity in these 9 sources can only be explained by black holes with masses
over $100~M_\mathrm{\odot}$. Our findings suggest the presence of LLAGN in
these galaxies, with broad H$\alpha$ line widths implying BH masses of
$10^4-10^6M_\mathrm{\odot}$. Given Green Peas' role as significant Lyman
Continuum leakers, LLAGN in these galaxies could have contributed significantly
to cosmic reionization.
