Determine the nature of J1350−0027

Determine whether the double-peaked Mg II profile of the z=6.49 quasar J1350−0027 is produced by a dust-obscured quasar whose visible emission is limited to narrow narrow-line-region lines or by a low-ionization broad-absorption-line quasar.

Background

The Subaru/MOIRCS spectrum of J1350−0027 shows a double-peaked feature near Mg II. The authors model it as resolved Mg II doublet emission, but note that the feature could instead be broad Mg II absorption superimposed on a broader emission component.

Because the spectrum has low signal-to-noise and no JWST rest-optical spectroscopy is currently available for the object, the physical interpretation cannot be determined. The object is therefore excluded from the statistical analysis of broad-line SHELLQs quasars.

References

However, given the low signal-to-noise ratio of the \ion{Mg}{2} spectrum and the absence of JWST spectroscopy currently available for this object, we cannot reliably distinguish between the dust-obscured quasar scenario and the low-ionization broad absorption line quasar scenario.

— SHELLQs. Black Hole Mass and Eddington Ratio Distributions of Intermediate-Luminosity Quasars at 6<z<7  (2609.09266 - Onoue et al., 8 Sep 2026) in Section 2.3.2, Notes on Individual Objects, J1350−0027