Interpreting the detection of anomalies in SDSS spectra

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Table 3

Emission line diagnostics for clusters 1–3.

Cluster	Balmer Decrement	[N II]/Hα	[O III]/Hβ	[O III]/ [O II]	O3N2
1	3.74–3.93	0.26–0.32	1.09–1.40	1.06–1.32	0.53–0.69
2	3.48–3.64	0.17–0.21	1.58–1.86	1.24–1.48	0.92–1.02
3	3.43–3.54	0.11–0.15	3.13–3.53	2.54–3.06	1.23–1.37

Notes. Key line ratios used in standard classification schemes. Each value represents the range between the 45th and 55th percentiles across cluster members based on SDSS pipeline measurements. These narrow intervals summarize the central trend while accounting for internal variability.

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