Signs of a dark object shaping a ‘tadpole’ of molecular gas

A peculiar cloud of gas, nicknamed the Tadpole because of its shape, may owe its shape to a dark, massive compact object, predictably a black hole 100,000 times more massive than the Sun.

A team of Japanese researchers led by Miyuki Kaneko of Keio University used data from the James Clerk Maxwell Telescope, operated by the East Asia Observatory, and the NAOJ (National Astronomical Observatory of Japan) Nobeyama 45-m radio telescope to identify an unusual cloud of molecular gas some 27,000 light-years away in the constellation Sagittarius.

This peculiar cloud of gas seems to revolve around a space devoid of bright objects. The “tadpole” shape strongly suggests that it is stretching as it orbits a massive compact object. The only problem is that, at the center of the Tadpole’s orbit, there are no bright objects that could be massive enough to hold the Tadpole gravitationally. The best candidate for this compact and massive invisible object is a black hole.

Since black holes do not emit light, the only way to detect them is when they interact with other objects. This leaves astronomers in the dark about how many black holes, and with what range of masses, might be lurking in the Milky Way.

Now the team plans to use the Atacama Large Millimeter/submillimeter Array (ALMA) to search for faint signals from a black hole, or other object, at the gravitational center of the Tadpole’s orbit.

The article is published in The Astrophysical Journal.