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Fiber 347

Emission Lines

The object in fiber 347 on plate 6498 has emission lines with an odd property. The emission lines appear to be combinations of two separate lines superimposed on each other. This is the case with emission lines in both the red and blue ends of the spectrum.

6498-56565-347 emission line

6498-56565-347 emission line

6498-56565-347 emission line

Emission line vs 2 Gaussians

Early ideas for the reason behind the form of the emission lines included a coadd of a good exposure with a bad exposure causing the superposition; however, upon looking at the emission lines for a single exposure shows that this is not the case.

exposure 0

exposure 1

Another idea was that the entire plate might have been problematic. To test this, I looked at sky fibers, specifically paying attention to the 5577 O I bright emission line. The emission line did not appear to be blended in any of the sky fibers I looked at.

sky fiber emission line

sky fiber emission line

sky fiber emission line


The model singled out by the pipeline as having the lowest reduced chi2 value has the following values associated:

  • CLASS QSO SUBCLASS AGN BROADLINE Z 0.0306970439851 Z_ERR 1.9324472305e-05 RCHI2 79.1368637085 RCHI2DIFF 21.0981826782 ZWARNING 0

347 best fit model

The second best fit model had the following associated information:

  • CLASS GALAXY SUBCLASS Z 0.0305971615016 Z_ERR 1.33473549795e-05 RCHI2 93.4059295654 RCHI2DIFF 6.82911682129 ZWARNING 0

347 second best fit model

The first model has a glaring deficiency in that it doesn't model anything past about 8600 Angstroms, but the second model seems no better at modeling the data. Both models do give similar redshift values, though I do not know if that is actually meaningful.