The eROSITA Final Equatorial Depth Survey (eFEDS) - SDSS spectroscopic observations of X-ray sources

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Volume 698 (June 2025)

A&A, 698 (2025) A132

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Table 2.

Criteria used to grade the visual inspections of the SDSS spectra.

Criteria	`NORMQ`	Notes
`ZWARNING` bit 7 (=128) is set	1	An unplugged or dropped fibre

Noted as Blazar-like during VI	–1	A likely Blazar or BL Lac object

(S/N > 2 and ZWARNING = 0 and 0 < z_err < 0.005
and N_conf3 ≥ 1 and z_pipe < z_max and $z_{pipe} \sim \bar{z_{vi}}$ $z_{\mathrm{pipe}} \sim \overline{z_{\mathrm{vi}}}$ )
OR
(S/N > 2 and ZWARNING = 0
and N_conf3 ≥ 1 and $s t d e v_{i} (z_{vi, i} / (1 + \bar{z_{vi}})) < 0.01$ $stdev_i(z_{\mathrm{vi},i}/(1+\overline{z_{\mathrm{vi}}})) < 0.01$ )	3	Secure redshift and classification confirmed by VI
OR
(S/N < 2 and $\bar{z_{conf}} > 2.5$ $\overline{z_{conf}} > 2.5$
and N_conf3 > 1 and $s t d e v_{i} (z_{vi, i} / (1 + \bar{z_{vi}})) < 0.01$ $stdev_i(z_{\mathrm{vi},i}/(1+\overline{z_{\mathrm{vi}}})) < 0.01$ )

$\bar{z_{conf}} > 2.0$ $\overline{z_{conf}} > 2.0$
and N_vi ≥ 1 and $s t d e v_{i} (z_{vi, i} / (1 + \bar{z_{vi}})) < 0.01$ $stdev_i(z_{\mathrm{vi},i}/(1+\overline{z_{\mathrm{vi}}})) < 0.01$	2	Less certain redshift+classification provided by VI

S/N > 2 and ZWARNING = 0 and 0 < z_err < 0.005
and N_vi = 0 and z_pipe < z_max	3	Trustworthy pipeline redshift+classification (no-VI)

Everything else	1	Low confidence in redshift+classification

Notes. The criteria are tested in sequence (from top to bottom), so later grades must have failed the criteria for all previous grades. N_conf3 is the number of visual inspections with Z_CONF = 3. The maximum trusted redshift depends on the classification, for CLASS=QSO we consider z_pipe < 3 safe and for CLASS=GALAXY we allow z_pipe < 0.8. The criterion $z_{pipe} \sim \bar{z_{vi}}$ $z_{\mathrm{pipe}} \sim \overline{z_{\mathrm{vi}}}$ is shorthand for $| z_{pipe} - \bar{z_{vi}} | / (1 + \bar{z_{vi}}) < 0.01$ $| z_{\mathrm{pipe}} - \overline{z_{\mathrm{vi}}} | / (1 + \overline{z_{\mathrm{vi}}}) < 0.01$ .

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