Pulsar motion hints at extra source of strong gravity in 47 Tucanae
NASA, ESA, Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration, J. Mack/STScI, G. Piotto/University of Padua
Medium-weight black holes may exist after all. Astronomers say signs of a black hole with about 2,200 times the mass of the sun have been detected at the center of the star cluster 47 Tucanae. If confirmed, the discovery could hint at a new class of black holes, ones starved of gas.
“It’s notoriously challenging to observe the centers of star clusters,” says Bülent Kiziltan of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. “We looked at how the stars in the cluster were being stirred up. Their dynamics suggest there has to be a black hole there.” A study appearing online February 8 in Nature describes the intermediate-mass black hole.
Kiziltan and colleagues studied pulsars, neutron stars that rotate rapidly and emit a beam of electromagnetic radiation. Observers on Earth see the beam as a regularly pulsed signal that can be used to track the