X-Ray, Optical, and Infrared Imaging and Spectral Properties of the 1 M[CLC]s[/CLC] Chandra Deep Field North Sources

We present the optical, near-infrared, submillimeter, and radio follow-upcatalog of the X-ray selected sources from the 1 Ms Chandra observation of theHubble Deep Field North region. We have B, V, R, I, and z' magnitudes for the370 X-ray point sources, HK' magnitudes for 276, and spectroscopic redshiftsfor 182. We present high-quality spectra for 175 of these. The redshiftdistribution shows indications of structures at z=0.843 and z=1.0175 (alsodetected in optical surveys) which could account for a part of thefield-to-field variation seen in the X-ray number counts. The fluxcontributions separated into unit bins of redshift show that the z<1spectroscopically identified sources already contribute about one-third of thetotal flux in both the hard and soft bands. We find from ratios of the X-raycounts that the X-ray spectra are well-described by absorption of an intrinsicGamma=1.8 power-law, with log NH values ranging from 21 to 23.7. We estimatethat the Chandra sources that produce 87% of the HEAO-A X-ray background (XRB)at 3 keV produce 57% at 20 keV, provided that at high energies the spectralshape of the sources continues to be well-described by a Gamma=1.8 power-law.However, when the Chandra contributions are renormalized to the BeppoSAX XRB at3 keV, the shape matches fairly well the observed XRB at both energies. Thus,whether a substantial population of as-yet undetected Compton-thick sources isrequired to completely resolve the XRB above 10 keV depends critically on howthe currently discrepant XRB measurements in the 1-10 keV energy range tietogether with the higher energy XRB. (Abridged)