CLASXS: Chandra X-Ray Survey of Lockman Hole-NW with Optical Counterparts

The Lockman Hole-Northwest field survey covers a contiguous 0.4 square degrees. It contains a catalog of 525 X-ray point sources and four extended sources, with optical B, V, R, I, z' photometry for 521 sources and spectroscopic redshifts for 271 sources. The table was created by NASA HEASARC in May 2005 from merged CDS tables.

Use Cases

• Analyze the contribution of different source populations to the 2-10 keV cosmic X-ray background based on the survey's bridging depth and area.
• Study the redshift and luminosity distribution of broad-line and non-broad-line active galactic nuclei based on the optical spectral type separation.
• Investigate the lack of luminous, high accretion rate sources at z < 1 by combining this survey with other Chandra and XMM-Newton hard X-ray surveys.
• Compare source clustering and redshift groupings with ultra-deep pencil-beam surveys like the Chandra Deep Fields based on the larger solid angle coverage.

Strengths

• Contains 525 X-ray point sources and four extended sources from a contiguous 0.4 square degree area.
• Provides optical photometry for 99% (521) of the X-ray sources and spectroscopic redshifts for 52% (271) of them.
• Reaches specific flux sensitivities: 5 x 10^-16 ergs/cm^2/s (0.4-2 keV) and 3 x 10^-15 ergs/cm^2/s (2-8 keV).

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.

Provenance

Source

NASA HEASARC, created from merged tables from Yang et al. 2005 and Steffen et al. 2005.

Collection Method

Observations from the Chandra ACIS-I instrument during 2001 April 30-May 17 and 2002 April 29-May 4, combined with optical and near-infrared photometric and spectroscopic follow-up.

Time Range

Observations conducted in 2001 and 2002.

Freshness

Last updated 2026-03-13 17:33:35.920132; freshness should be verified.

Geography

The Lockman Hole-Northwest (LHNW) field in the sky.