Telescopes unite in unprecedented observations of the famous black hole

In April 2019, scientists released the first image of a black hole in the M87 galaxy using the Event Horizon Telescope (EHT). However, this remarkable achievement was only the beginning of the science story that had to be told.

Data from 19 observatories released today promise to provide unparalleled insight into this black hole and the system that drives it, and to improve the tests of Einstein’s General Theory of Relativity.

“We knew the first direct image of a black hole would be groundbreaking,” said Kazuhiro Hada of the National Astronomical Observatory of Japan, a co-author of a new study published in The astrophysical journal letters which describes the large set of data. “But to make the most of this remarkable image, we need to know everything we can about the black hole’s behavior at that time, by observing the entire electromagnetic spectrum.”

The tremendous gravity of a supermassive black hole can drive rays of particles that move near the speed of light over great distances. M87’s rays produce light that spans the entire electromagnetic spectrum, from radio waves to visible light to gamma rays. This pattern differs for each black hole. Identifying this pattern provides important insight into the characteristics of a black hole, for example the spin and energy output, but it is a challenge because the pattern changes over time.

Scientists have compensated for this volatility by coordinating observations with many of the world’s most powerful telescopes on the ground and in space, and collecting light from across the spectrum. These 2017 observations were the largest simultaneous observation campaign ever undertaken on a supermassive black hole with rays.

Three Observatories Managed by the Center for Astrophysics | Harvard & Smithsonian participated in the landmark campaign: the Submillimeter Array (SMA) in Hilo, Hawaii; the space-based Chandra X-ray Observatory; and the Very Energetic Radiation Imaging Telescope Array System (VERITAS) in southern Arizona.

From the EHT’s now iconic image of M87, a new video takes viewers on a journey through the data of each telescope. Each successive frame shows data on many factors of ten in scale, both of wavelengths of light and physical size.

The series begins with the image of the black hole in April 2019. It then moves through images of other radio telescope arrays from around the world (SMA) and moves outward into the field of view during each step. Then the view changes to telescopes that detect visible light, ultraviolet light and X-rays (Chandra). The screen is divided to show how these images, covering the same amount of air at the same time, compare with each other. The series ends by showing what gamma ray telescopes on the ground (VERITAS) and Fermi detect in space from this black hole and its ray.

Each telescope provides different information about the behavior and impact of the 6.5 billion solar mass of black hole in the center of M87, which is located approximately 55 million light-years from Earth.

“There are several groups who are eager to see if their models match these rich observations, and we are excited to see the whole community using this public dataset to help us better the deep ties between black holes and their rays. to understand, “says co-author Daryl Haggard of McGill University in Montreal, Canada.

The data was collected by a team of 760 scientists and engineers from nearly 200 institutions, spanning 32 countries or regions, and using observatories funded by agencies and institutions around the world. The observations were concentrated from the end of March to mid-April 2017.

“This incredible series of observations contains many of the best telescopes in the world,” says co-author Juan Carlos Algaba of the University of Malaya in Kuala Lumpur, Malaysia. “This is a wonderful example of astronomers around the world working together in the pursuit of science.”

The first results show that the intensity of the light produced by M87’s supermassive black hole was the lowest ever observed. This created ideal conditions to see the ‘shadow’ of the black hole, and to isolate the light from areas near the event horizon of those tens of thousands of light years from the black hole.

The combination of data from these telescopes, and current (and future) EHT observations, will enable scientists to conduct important lines of inquiry into some of the most important and challenging fields of study of astrophysics. Scientists, for example, plan to use this data to improve the tests of Einstein’s theory of general relativity. Uncertainty about the material that revolves around the black hole and is blown away in rays, especially the properties that determine the emitted light, is currently a major obstacle to these General Relativity Tests.

A related question addressed by today’s study concerns the origin of energetic particles called ‘cosmic rays’, which are constantly bombarding the earth from outer space. Their energy can be a million times higher than what can be produced in the most powerful accelerator on earth, the Large Hadron Collider. The enormous jets launched from black holes, such as those shown in today’s images, are considered the most likely source of cosmic rays with the highest energy, but there are many questions about the details, including the exact locations of the particles. be accelerated. Because cosmic rays produce light through their collisions, the gamma rays with the highest energy can determine this location, and the new study indicates that these gamma rays are unlikely to be produced near the horizon of events – at least not in 2017. debate will be compared to the observations from 2018, and the new data collected this week.

“Understanding particle acceleration is very important for our understanding of both the EHT image and the rays in all their ‘colors’,” says co-author Sera Markoff of the University of Amsterdam. “These radiators succeed in exporting energy released through the black hole to scales larger than the host system, such as a large power cord. Our results will help us calculate the amount of power carried, and the effect that has the rays of the black hole on its surroundings. “

The release of this new treasure trove of data coincides with the EHT’s observation run in 2021, which uses a global range of radio dishes, the first since 2018. Last year’s campaign was canceled due to the COVID-19 pandemic, and the previous year was suspended. due to unforeseen technical problems. This week, for six nights, EHT astronomers are pointing at several supermassive black holes: the one in M87, the one in our Milky Way called Sagittarius A * and a few more black holes in the distance. Compared to 2017, the array has been improved by adding three more radio telescopes: the Greenland Telescope, the Kitt Peak 12-meter telescope in Arizona and the Northern Extended Millimeter Array (NOEMA) in France.

“With the release of these data, combined with the resumption of observation and an improved EHT, we know that many exciting new results are imminent,” said co-author Mislav Balokovic of Yale University.

“I am very excited to see these results appear, along with my colleagues working on the SMA, some of whom were directly involved in gathering the data for this spectacular view in M87,” says co-author Garrett Keating, a scientist from the Submillimeter Array project. “And with the outcome of Sagittarius A * – the massive black hole in the middle of the Milky Way – coming out soon, and the resumption of observation this year, we look forward to more amazing results with the EHT for the coming year. ”