2004/02/26 by T. Miyaji, Takamitsu Miyaji, Vicki L. Sarajedini +10
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/420807
published as Astron.J. 127 (2004) 3180 · 18 pages, 6 figures, accepted for publication in Astronomical Journal
arxiv created 2004/02/26 · openalex publication_date 2004/06/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We summarize the multiwavelength properties of X-ray sources detected in the 80 ks XMM-Newton observation of the Groth-Westphal strip, a contiguous strip of 28 Hubble Space Telescope Wide Field Planetary Camera 2 (WFPC2) images. Among the ≈150 X-ray sources detected in the XMM-Newton field of view, 23 are within the WFPC2 fields. Ten spectroscopic redshifts are available from the Deep Extragalactic Evolutionary Probe and Canada-France Redshift Survey projects. Four of these show broad Mg II emission and can be classified as type 1 active galactic nuclei (AGNs). Two of those without any broad lines, nevertheless, have [Ne V] emission, which is an unambiguous signature of AGN activity. One is a narrow-line Seyfert 1 and the other a type 2 AGN. As a follow-up, we have made near-infrared spectroscopic observations using the OHS/CISCO spectrometer for five of the X-ray sources for which we found no indication of AGN activity in the optical spectrum. We have detected Hα + [N II] emission in four of them. A broad Hα component and/or a large [N II]/Hα ratio is seen, suggestive of AGN activity. Nineteen sources have been detected in the K s band, and four of these are extremely red objects (EROs) ( I 814 - K s > 4). The optical counterparts for the majority of the X-ray sources are bulge-dominated. The I 814 - K s color of these bulge-dominated hosts are indeed consistent with evolving elliptical galaxies, while contaminations from star formation/AGNs seems to be present in their V 606 - I 814 color. Assuming that the known local relations among the bulge luminosity, central velocity dispersion, and the mass of the central blackhole still hold at z ∼ 1, we compare the AGN luminosity with the Eddington luminosity of the central blackhole mass. The AGN bolometric luminosity to Eddington luminosity ratio ranges from 0.3% to 10%.