Although the reason for the connection remains uncertain, the result is a more precise formula and increased confidence in its validity. “The strength of the correlation is competitive with, if not better than, all our other methods used to predict black hole masses,” Davis said in a statement. “Anyone can now look at an image of a spiral galaxy and immediately gauge how massive its black hole should be.”
An extra feature of the refinement is a greater capacity to extrapolate the relationship to galaxies with loosely wound arms. This is important because astronomers have put a lot of work into the search for intermediate-mass black holes, which fall between those left behind by the collapse of large stars and the giant ones at the heart of galaxies like our own. Davis thinks we could find these by searching for galaxies with extremely loose spirals.
One of the reasons astronomers are so keen to find intermediate-mass black holes is the expectation that these are more likely to be undergoing mergers that could produce gravitational waves. Since the capacity of the Laser Interferometer Gravitational-Wave Observatory (LIGO) to detect waves was confirmed last year, the idea of knowing where to look in the future is exciting and this work provides helpful suggestions.