Sign in to view source links and access this dataset
Description
1005 quasars with unusual spectra were selected from the Sloan Digital Sky Survey Data Release 7 using Kohonen self-organising maps. The catalog, created by NASA HEASARC in May 2012, groups spectra into seven types dominated by broad absorption lines, unusual red continua, weak emission lines, or strong iron emission. Redshifts range from 0.497 to 4.771.
Use Cases
Classifying unusual quasar types based on spectral features like broad absorption lines or strong iron emission.
Studying the relationship between spectral type and properties like redshift and absolute magnitude.
Selecting rare and interesting quasar candidates for targeted follow-up observations.
Analyzing the distribution of radio loudness among different classes of peculiar quasars.
Strengths
Contains 1005 confirmed unusual quasars, providing a sizable sample for statistical analysis.
Spectra are categorized into seven distinct types with quantified prevalence (e.g., 42% broad absorption lines).
Includes derived parameters like redshift, absolute magnitude, spectral type, and a peculiarity index.
Limitations
The compilation is explicitly not aimed at completeness in a quantifiable sense.
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 Sloan Digital Sky Survey Data Release 7.
Collection Method
Selected by means of Kohonen self-organising maps applied to the SDSS spectroscopic database.
Time Range
Observational data from Sloan Digital Sky Survey Data Release 7 (2009).
Freshness
Last updated 2026-03-13 20:03:20.156759; freshness should be verified.
Geography
Celestial survey data; spatial coverage is not specified.
License is listed as 'other-license-specified'; terms should be reviewed before use.