M87 is one of the most spectacular elliptical galaxies. What makes it so cool is its black-hole-powered jet moving to near light-speed.
Astrophysical jets originate near supermassive black holes at the center of active galaxies. They carry so much energy they can outshine an entire galaxy.
The American astronomer Heber Curtis discovered the first astrophysical jet in 1918 in the nearby galaxy M87 at the center of the Virgo cluster. He described it as a “curious straight ray” extending from the galactic nucleus.
In the 1950s when the field of radio was blossoming, one of the brightest radio sources in the sky, Virgo A, was discovered to be associated with M87 and its jet.
Attracted by strong gravity, matter falls towards the central black hole as it feeds on the surrounding gas and dust. But instead of falling into the black hole, a small fraction of particles accelerate close to the speed of light and shoot out in two narrow beams along the axis of rotation of the black hole.
These jets may be the fastest-traveling particles in the Universe. They act as conduits for transporting energy over intergalactic distances which in some cases exceeds a million light-years.
Viewing such a jet face-on from Earth is what we call a blazar.
On Wednesday, April 10th, 2019, the Event Horizon Telescope treated the world to something beautiful – the first-ever image of a black hole. Specifically, the image captured the Supermassive Black Hole at the center of M87.
This was truly historical. People compared it to pictures like the “pale blue dot” taken by the Voyager 1 mission or the “Earthrise” image taken by Apollo 8.
In 2021, two years after the Event Horizon Telescope produced the first black hole image, they published a new view of the massive object at the center of the M87 galaxy.
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The new image reveals how the M87 central supermassive black hole looks in polarized light.
The Messier 87 galaxy lies 55 million light-years away in the constellation Virgo. This spherical city is home to several trillion stars, a supermassive black hole, and a family of about 15,000 globular star clusters, each one an island universe of its own.
The supermassive black hole at the center of M87 is a monster, 6.5 billion times as massive as the Sun but is only 38 billion km (24 billion miles) across.
What makes it even more fascinating is its jet of subatomic particles traveling at nearly the speed of light. You can clearly see it in this image caught by the Hubble Space Telescope.
The jet extends from the central supermassive black hole of the galaxy and reaches out about 5,000 light-years. It is visible in optical light, as well as X-rays, and radio emissions.
Scientists believe the mighty jets of M87’s supermassive black hole are produced when a dense disk of matter — called an accretion disk — whirls around the black hole at up to 2 million miles per hour (3.5 million km/h). The material within the accretion disk grinds together as it circles, with the innermost regions spinning faster than those farther out. This differential rotation causes the magnetic fields to get coiled up, ejecting the material falling into the black hole at nearly the speed of light.
The light that we see (and the radio emission) is produced by electrons twisting along magnetic field lines in the jet. Scientists call this process synchrotron radiation, which gives the jet its bluish tint.
M87 is one of the nearest and is the most well-studied astrophysical jet, but countless others exist out there.
Wherever a massive black hole is feeding on a particularly rich diet of disrupted stars, gas, and dust, the conditions are right for the formation of a jet.
M87 galaxy has a diameter of about 120,000 light-years, slightly bigger than the Milky Way.
However, this galaxy is far denser and its trillion member stars form a voluminous ball rather than a disc.
Messier 87 helps anchor the roughly 2,000 galaxies — including the Milky Way — that make up our local cosmic city, dubbed the Virgo Cluster. In turn, the Virgo Cluster is a primary component of the much larger Virgo Supercluster.
Observations taken with the European Southern Observatory’s Very Large Telescope have revealed that the giant galaxy has swallowed an entire medium-sized galaxy over the last billion years. Astronomers have been able to track the motions of 300 glowing planetary nebulae to find clear evidence of this event, and also evidence of excess light coming from the remains of the totally disrupted victim.