North Celestial Pole Radio Source Catalog from 21CMA Observations

624 radio sources detected around the North Celestial Pole using the 21 Centimeter Array (21CMA) interferometer. The catalog is derived from a 12-hour observation on 2013 April 13, covering frequencies from 75 to 175 MHz with an angular resolution of approximately 4 arcminutes. It includes flux densities across eight sub-bands and in-band spectral indices for each source.

Use Cases

• Analyzing low-frequency source counts and the flattening trend for fainter sources based on flux density data.
• Studying the spectral properties of radio sources based on the provided in-band spectral indices.
• Benchmarking interferometer performance and calibration challenges based on the described limitations like dynamical range and grating lobes.
• Informing the design of future low-frequency arrays like the SKA based on the analysis of extended source removal challenges.

Strengths

• Catalog of 624 distinct radio sources provides a substantive sample for analysis.
• Data from a dedicated 12-hour observation with a defined frequency coverage (75-175 MHz) and angular resolution (~4 arcminutes).
• Includes multi-band flux densities and spectral indices, suggesting detailed spectral information per source.

Limitations

• The analysis is restricted to east-west baselines within 1500 m only, which may limit the completeness of the interferometric data.
• Dynamical range and sensitivity are noted to be limited by calibration and deconvolution errors, particularly from grating lobes of bright sources.
• Column-level documentation is absent; field semantics must be inferred after download.

Provenance

Source

National Aeronautics and Space Administration

Collection Method

Observational data from the 21 Centimeter Array (21CMA) radio interferometer.

Time Range

Observation date: 2013 April 13.

Freshness

Last updated 2026-03-13 17:56:50.594354; freshness should be verified.

Geography

Observations centered on the North Celestial Pole (within 5 degrees). The array is sited in the Ulastai valley of western China.