I will review the physical and statistical properties of dust-obscured AGN viewed with multi-wavelength data. In particular, I mainly focus on infrared (IR)-bright dust-obscured galaxies (DOGs) with i – [22] > 7.0 in AB magnitude and with flux density at 22 ｵ m > 1.0 mJy. IR-bright DOGs are a subset of high-redshift (z~1-3) optically-faint luminous IR galaxies (such as ULIRGs and HyLIRGs). A hydrodynamic simulation has indicated that black holes in IR-bright DOGs are expected to show the highest accretion rate during a major merger event, suggesting that IR-bright DOGs are expected to harbor the black holes in the growing phase.

Therefore, IR-bright DOGs may constitute a key population for understanding the co-evolution of galaxies and supermassive black holes.
However, these IR-bright DOGs are spatially rare, so wide-area surveys with optical and IR are strongly required to detect these bright but spatially rare populations. So far, we have performed a systematic search for obscured AGN (incl. DOGs) and investigated their statistical and physical properties based on multi wavelength data, such as SDSS, Subaru/HSC, WISE, AKARI, ALMA, NuSTAR, and eROSITA. In this talk, I particularly discuss the following properties: (i) luminosity function and luminosity density, (ii) clustering properties, (iii) ionized and molecular gas properties, (iv) AGN and host properties.