Spectral Lines Associated with Dark Matter

In recent News from Physics and Cosmology, there has been a flurry of reports concerning a signature spectral line which can be associated with dark matter in distant galaxies. Given the preponderance of hydrogen in normal matter, there has been a suspicion that dark matter is novel form of hydrogen. "An unidentified line in X-ray spectra of the Andromeda galaxy and Perseus galaxy cluster" by Boyarsky is an example. Although the line is weak, it has a tendency to become stronger towards the centers of the galaxies and is absent in the spectrum of a deep "blank sky" dataset.