Properties of Near-Infrared Selected AGN Candidates with 2MASS/ROSAT
  Catalogues
  We report on the near-infrared selected AGN candidates extracted from
2MASS/ROSAT catalogues and discuss their properties. First, near-infrared
counterparts of a X-ray source in ROSAT catalogues (namely, Bright Source
Catalogue (BSC) and Faint Source Catalogue (FSC)) were extracted by positional
cross-identification of <=30''. Because these counterparts would contain many
mis-identifications, we further imposed near-infrared colour selection criteria
and extracted reliable AGN candidates (BSC: 5,273, FSC: 10,071). Of 5,273
(10,071) candidates in the BSC (FSC), 2,053 (1,008) are known AGNs.
Near-infrared and X-ray properties of candidates show similar properties with
known AGNs and are consistent with previous studies. We also searched for
counterparts in other wavelengths (that is, optical, near-infrared, and radio),
and investigated properties in multiwavelength. No significant difference
between known AGNs and unclassified sources could be seen. However, some
unclassified sources in the FSC showed slightly different properties compared
with known AGNs. Consequently, it is highly probable that we could extract
reliable AGN candidates though candidates in the FSC might be spurious.
