Observations: Some supermassive black holes may not be so super after all

Observations: Some supermassive black holes may not be so super after all: "Kollatschny and Zetzl's analysis found that rotation is the primary driver of spectral line widening, allowing them to use the width of measured hydrogen lines to infer the velocity of the swirling gas and hence the mass of the object at the disk's center. Their method indicates that the mass of distant AGN black holes as estimated by other spectral methods is two to 10 times too high."