AGN selection by 18-band SED fitting in mid-infrared in the AKARI NEP
  deep field
  In this research, we provide a new, efficient method to select infrared (IR)
active galatic nucleus (AGN). In the past, AGN selection in IR had been
established by many studies using color-color diagrams. However, those methods
have a problem in common that the number of bands is limited. The AKARI North
Ecliptic Pole (NEP) survey was carried out by the AKARI Infrared Camera (IRC),
which has 9 filters in mid-IR with a continuous wavelength coverage from 2 to
24$\mu$m$^{-1}$. Based on the intrinsic different mid-IR features of AGN and
star-forming galaxies (SFGs), we performed SED fitting to separate these two
populations by the best-fitting model. In the X-ray AGN sample, our method by
SED fitting selects 50$\%$ AGNs, while the previous method by colour criteria
recovers only 30$\%$ of them, which is a significant improvement. Furthermore,
in the whole NEP deep sample, SED fitting selects two times more AGNs than the
color selection. This may imply that the black hole accretion history could be
more stronger than people expected before.
