Pair of supermassive black holes found at the heart of galaxy Mrk 501

An international team led by Silke Britzen of MPIfR found a second jet in galaxy Mrk 501, the first direct imaging evidence of a supermassive black hole pair. The two objects orbit each other about every 121 days and could merge in as little as 100 years.

• Second jet in Mrk 501 tracked in radio data spanning 23 years
• Orbital period of the pair estimated at 121 days
• Separation is 250–540 times the Earth-Sun distance
• Merger within 100 years could be seen by pulsar timing arrays