NGC 55 Chandra X-Ray Point Source Catalog with 154 High-Significance Sources

154 high-significance X-ray point sources were detected in the SB(s)m galaxy NGC 55 as part of the Chandra Local Volume Survey. The HEASARC created this table in September 2015 based on machine-readable data from the reference paper, which includes hardness ratios and cross-correlations with Hubble Space Telescope observations. Combined archival Chandra observations provide an effective exposure time of 56.5 ks, with sources detected down to a limiting luminosity of ~5e35 erg/s.

Use Cases

• Classifying X-ray sources as likely X-ray binaries, background AGN, supernova remnants, or foreground stars based on cross-correlations with optical counterparts.
• Analyzing X-ray hardness ratios and spectral properties for point sources in a nearby galaxy.
• Studying the radial distribution of X-ray sources within NGC 55.
• Investigating temporal variability of high-significance X-ray detections.
• Integrating this catalog with other CLVS galaxy catalogs for a broader analysis of 629 X-ray sources across five nearby galaxies.

Strengths

• Sources are filtered for high statistical significance with a Poisson probability threshold (pns < 4e-6).
• Catalog is part of a larger survey (CLVS) containing 629 total sources across five galaxies.
• Data includes multi-wavelength cross-correlations with Hubble Space Telescope observations for source classification.
• Effective exposure time of 56.5 ks from combined archival Chandra observations.

Limitations

• Excludes 76 lower-significance sources (4e-6 < pns < 1e-3) that may be genuine.
• 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, based on data from Binder et al. reference paper.

Collection Method

Source detection using iterative runs of wavdetect and ACIS-Extract on Chandra ACIS-I observations.

Time Range

Observations from 2001 September 11 and 2004 June 29.

Freshness

Last updated 2026-03 13 16:27:41.874698; freshness should be verified.

Geography

Target is the galaxy NGC 55, a member of the Sculptor group.