“A Galaxy Fell Through It” –Creating the EHT’s Monster M87 Black Hole

M87 Black Hole & Jet


“A medium-sized galaxy fell through the center of M87, and as a consequence of the enormous gravitational tidal forces, its stars are now scattered over a region that is 100 times larger than the original galaxy!” said Ortwin Gerhard, head of the dynamics group at the Max Planck Institute for Extraterrestrial Physics about the monster elliptical galaxy that harbors the now iconic black hole the size of our solar system imaged for the first time ever by the Event Horizon Telescope (EHT) on April 10, 2019.

New observations July 2018 with ESO’s Very Large Telescope revealed that the giant elliptical galaxy Messier 87 swallowed an entire medium-sized galaxy ohttps://dailygalaxy.com/2019/04/paradoxical-intriguing-frightening-captured-the-black-hole-bigger-than-our-solar-system/ver the last billion years. The Event Horizon Telescope (EHT) team theorized that the M87 black hole grew to its massive size by merging with several other black holes. M87 is the largest, most massive galaxy in the nearby universe, and is thought to have been formed by the merging of 100 or so smaller galaxies including the one described above. The M87 black hole’s large size and relative proximity, astronomers think that it could be the first black hole that they could actually “see.”

“Paradoxical, Intriguing, Frightening” –The Black Hole Bigger Than Our Solar System


M87 Black Hole Jets


M87, imaged above by NASA’s Spitzer Space Telescope, is home to the  supermassive black hole that spews two jets of material out into space at nearly the speed of light. The inset shows a close-up view of the shockwaves created by the two jets. This image from NASA’s Spitzer Space Telescope shows the entire M87 galaxy in infrared light. The EHT image, by contrast, relied on light in radio wavelengths and showed the black hole’s shadow against the backdrop of high-energy material around it.


M87 Galaxy & Black Hole


On the right is the first-ever image of the black hole at the heart of galaxy M87, taken by the Event Horizon Telescope. The NASA Chandra X-ray Observatory’s wide-field view of the M87 galaxy (left) reveals the jet of high-energy particles launched by the intense gravitational and magnetic fields around the black hole. Credit: X-ray (left): NASA/CXC/Villanova University/J. Neilsen; Radio (right): Event Horizon Telescope Collaboration.

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Located about 55 million light-years from Earth, M87 has been a subject of astronomical study for more than 100 years and has been imaged by many NASA observatories, including the Hubble Space Telescope, the Chandra X-ray Observatory and NuSTAR. In 1918, astronomer Heber Curtis first noticed “a curious straight ray” extending from the galaxy’s center. This bright jet of high-energy material, produced by a disk of material spinning rapidly around the black hole, is visible in multiple wavelengths of light, from radio waves through X-rays. When the particles in the jet impact the interstellar medium (the sparse material filling the space between stars in M87), they create a shockwave that radiates in infrared and radio wavelengths of light but not visible light. In the Spitzer image, the shockwave is more prominent than the jet itself.

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The brighter jet, located to the right of the galaxy’s center, is traveling almost directly toward Earth. Its brightness is amplified due to its high speed in our direction, but even more so because of what scientists call “relativistic effects,” which arise because the material in the jet is traveling near the speed of light. The jet’s trajectory is just slightly offset from our line of sight with respect to the galaxy, so we can still see some of the length of the jet. The shockwave begins around the point where the jet appears to curve down, highlighting the regions where the fast-moving particles are colliding with gas in the galaxy and slowing down.

The second jet, by contrast, is moving so rapidly away from us that the relativistic effects render it invisible at all wavelengths. But the shockwave it creates in the interstellar medium can still be seen here.

Located on the left side of the galaxy’s center, the shockwave looks like an inverted letter “C.” While not visible in optical images, the lobe can also be seen in radio waves, as in this image from the National Radio Astronomy Observatory’s Very Large Array.


M87 Black Hole & Jets


By combining observations in the infrared, radio waves, visible light, X-rays and extremely energetic gamma rays, scientists can study the physics of these powerful jets. Scientists are still striving for a solid theoretical understanding of how gas being pulled into black holes creates outflowing jets.

Infrared light at wavelengths of 3.6 and 4.5 microns are rendered in blue and green, showing the distribution of stars, while dust features that glow brightly at 8.0 microns are shown in red. The image was taken during Spitzer’s initial “cold” mission.


As a typical elliptical galaxy, it primarily contains old, fairly cold stars – they cause the reddish color of the galaxy in this color image. The powerful jet, however, is extremely energetic and emits much of its energy in the blue and ultraviolet parts of the spectrum. The jet, therefore, appears bright blue in comparison.

This image is a color composite of three images taken in ultraviolet, blue, and visible light (U, B and V filtres) during the night of May 25 – 26, 1998. In reality, the bright blue color of the jet corresponds to ultraviolet radiation.

The Daily Galaxy via JPL/Caltech 


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