Narrow-line X-Ray-selected Galaxies in the Chandra-COSMOS Field. I. Optical Spectroscopic Catalog

Abstract

The COSMOS survey is a large and deep survey with multiwavelength observations of sources from X-rays to the UV, allowing an extensive study of their properties. The central 0.9 deg² of the COSMOS field have been observed by Chandra with a sensitivity up to 1.9 × 10^-16 erg cm^-2 s^-1 in the full (0.5-10 keV) band. Photometric and spectroscopic identification of the Chandra-COSMOS (C-COSMOS) sources is available from several catalogs and campaigns. Despite the fact that the C-COSMOS galaxies have a reliable spectroscopic redshift in addition to a spectroscopic classification, the emission-line properties of this sample have not yet been measured. We present here the creation of an emission-line catalog of 453 narrow-line sources from the C-COSMOS spectroscopic sample. We have performed spectral fitting for the more common lines in galaxies ([O II] λ3727, [Ne III] λ3869, Hβ, [O III] λλ4959, 5007, Hα, and [N II] λλ6548, 6584). These data provide an optical classification for 151 (I.e., 33%) of the C-COSMOS narrow-line galaxies based on emission-line diagnostic diagrams.