Supermassive black holes (SMBH) reside in the center of galaxies like the Milky Way. They are mind-bogglingly massive, ranging from 1 million to 10 billion solar masses. Their smaller brethren, intermediate-mass black holes (IMBH), ranging between 100 and 100,000 solar masses, are harder to find.
Astronomers have spotted an intermediate-mass black hole destroying a star that got too close. They’ve learned a lot from their observations and hope to find even more of these black holes. Observing more of them may lead to understanding how SMBHs got so massive.
When a star gets too close to a powerful black hole, a tidal disruption event (TDE) occurs. The star is torn apart and its constituent matter is drawn to the black hole, where it gets caught in the hole’s accretion disk. The event releases an enormous amount of energy, outshining all the stars in the galaxy for months, even years.
That’s what happened with TDE 3XMM J215022.4-055108, which is more readily known as TDE J2150. Astronomers were only able to spot the elusive IMBH because of the burst of x-rays emitted by the hot gas from the star as it was torn apart. J2150 is about 740 million light-years from Earth in the direction of the Aquarius constellation. Now a team of researchers has used observations of the distant J2150 and existing scientific models to learn more about the IMBH.
They’ve published their results in a paper titled “Mass, Spin, and Ultralight Boson Constraints from the Intermediate Mass Black Hole in the Tidal Disruption Event 3XMM J215022.4?055108.” The lead author is Sixiang Wen from the University of Arizona. The paper is published in The Astrophysical Journal.
IMBHs are elusive and difficult to study. Astronomers have found several of them in the Milky Way and in nearby galaxies. Mostly they’ve been spotted because of their low-luminosity active galactic nuclei. In 2019 the LIGO and Virgo gravitational wave observatories spotted a gravitational wave from the merger of two IMBHs. As it stands now, there’s a catalogue of only 305 IMBH candidates, even though scientists think they could be common in galactic centers.
One of the problems in seeing them is their low mass itself. While SMBHs can be found by observing how their mass affects the stellar dynamics of nearby stars, IMBHs are typically too small to do the same. Their gravity isn’t powerful enough to change the orbits of nearby stars.
“The fact that we were able to catch this black hole while it was devouring a star offers a remarkable opportunity to observe what otherwise would be invisible,” said Ann Zabludoff, UArizona professor of astronomy and co-author on the paper. “Not only that, by analyzing the flare we were able to better understand this elusive category of black holes, which may well account for the majority of black holes in the centers of galaxies.”
It was the eruption of x-rays that made the event visible. The team compared the observed x-rays with models and was able to confirm the presence of an IMBH. “The X-ray emissions from the inner disk formed by the debris of the dead star made it possible for us to infer the mass and spin of this black hole and classify it as an intermediate black hole,” lead author Wen said.
This is the first time that observations have been detailed enough to be able to use a TDE flare to confirm the presence of an IMBH. It’s a big deal, because though we know that SMBHs lie in the center of galaxies like the Milky Way and larger, our understanding of smaller galaxies and their IMBHs is much more limited. They’re just really hard to see.
“We still know very little about the existence of black holes in the centers of galaxies smaller than the Milky Way,” said co-author Peter Jonker of Radboud University and SRON Netherlands Institute for Space Research, both in the Netherlands. “Due to observational limitations, it is challenging to discover central black holes much smaller than 1 million solar masses.”
The mystery surrounding IMBHs feeds into the mystery surrounding SMBHs. We can see SMBHs at the heart of large galaxies, but we don’t know exactly how they got that massive. Did they go through mergers? Maybe. Through the accretion of matter? Maybe. Astrophysicists mostly agree that both mechanisms may play a role.
Another question surrounds SMBH “seeds.” The seeds could be IMBHs of tens or hundreds of solar masses. The IMBHs themselves could’ve grown from stellar-mass black holes that grew into IMBHs through the accretion of matter. Another possibility is that long before there were actual stars, there were large gas clouds that collapsed into quasi-stars, that then collapsed into black holes. These strange entities would collapse directly from quasi-star to black hole without ever becoming a star, and are known as direct collapse black holes. But these are all hypotheses and models. Astrophysicists need more actual observations, like in the case of TDE J2150, to confirm or rule anything out.
“Therefore, if we get a better handle of how many bona fide intermediate black holes are out there, it can help determine which theories of supermassive black hole formation are correct,” Jonker said.
The team of researchers was also able to measure the black hole’s spin, which has implications for black hole growth, and maybe for particle physics, too. The black hole is spinning quickly, but it’s not spinning as fast as possible. It begs the question, how did the IMBH attain a speed in this range? The spin opens up some possibilities and eliminates others.
“It’s possible that the black hole formed that way and hasn’t changed much since, or that two intermediate-mass black holes merged recently to form this one,” Zabludoff said. “We do know that the spin we measured excludes scenarios where the black hole grows over a long time from steadily eating gas or from many quick gas snacks that arrive from random directions.”
The spin rate may shed some light on potential particle candidates for dark matter, too. One of the hypotheses says that dark matter is made up of particles never seen in a laboratory, called ultralight bosons. These exotic particles, if they exist, would have less than one-billionth the mass of an electron. The IMBHs spin rate may preclude the existence of these candidate particles.
“If those particles exist and have masses in a certain range, they will prevent an intermediate-mass black hole from having a fast spin,” co-author Nicholas Stone said. “Yet J2150’s black hole is spinning fast. So, our spin measurement rules out a broad class of ultralight boson theories, showcasing the value of black holes as extraterrestrial laboratories for particle physics.”
This discovery will build toward a better understanding of dwarf galaxies and their black holes, too. But for that to happen, astrophysicists need to observe more of these IMBH tidal disruption events.
“If it turns out that most dwarf galaxies contain intermediate-mass black holes, then they will dominate the rate of stellar tidal disruption,” Stone said. “By fitting the X-ray emission from these flares to theoretical models, we can conduct a census of the intermediate-mass black hole population in the universe,” Wen added.
As is often the case in astronomy, astrophysics, and cosmology, future telescopes and observatories should advance our knowledge considerably. In this, the Vera C. Rubin Observatory could play a role. The Rubin could discover thousands of TDEs each year.
Then we may finally be able to piece together the story of not only IMBHs but also SMBHs.
Russian actor and director making first movie in space return to Earth after 12-day mission
A Russian actor and a film director making the first move film in space returned to Earth on Sunday after spending 12 days on the International Space Station (ISS).
The Soyuz MS-18 Space capsule carrying Russian ISS crew member Oleg Novitskiy, Yulia Peresild and Klim Shipenko landed in a remote area outside the western Kazakhstan at 07:35 a.m. (0435 GMT), the Russian space agency Roscosmos said.
The crew had dedocked from the ISS three hours earlier.
Russian State TV footage showed the reentry capsule descending under its parachute above the vast Kazakh steppe, followed by ground personnel assisting the smiling crew as they emerged from the capsule.
However, Peresild, who is best known for her role in the 2015 film “Battle for Sevastopol”, said she had been sorry to leave the ISS.
“I’m in a bit of a sad mood today,” the 37-year-old actor told Russian Channel One after the landing.
“That’s because it had seemed that 12 days was such a long period of time, but when it was all over, I didn’t want to bid farewell,” she said.
Last week 90-year-old U.S. actor William Shatner – Captain James Kirk of “Star Trek” fame – became the oldest person in space aboard a rocketship flown by billionaire Jeff Bezos’s company Blue Origin.
Peresild and Shipenko have been sent to Russian Star City, the home of Russia’s space programme on the outskirts of Moscow for their post-flight recovery which will take about a week, Roscosmos said.
(Reporting by Vladimir Soldatkin; Editing by Raissa Kasolowsky)
Health Canada recalls BC cannabis product due to powdery mildew contamination – Aldergrove Star – Aldergrove Star
Health Canada and Joint Venture Craft Cannabis have issued a recall notice on a B.C.-based cannabis product due to contamination from powdery mildew.
The recall affects a batch of Bud Coast–Saltspring OG Shark dried cannabis in 3.5 gram units distributed by the B.C. Liquor Distribution Branch. According to Health Canada’s recall notice, 1,071 units were sold between Sept. 22 and Oct. 7
“The affected product may contain powdery mildew. In certain individuals, exposure may result in allergic symptoms such as sneezing, coughing, wheezing, runny nose or nasal congestion, and watery or itchy eyes,” the notice reads.
Anyone who may have purchased the contaminated cannabis should stop using the product immediately and return the product to the retailer where they purchased it.
Exposure to mouldy cannabis products can cause temporary adverse health consequences, but neither Health Canada nor Joint Venture have received any adverse reaction reports about the recalled cannabis.
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NASA launches first space probe to study Jupiter's Trojan asteroids – Ottawa Citizen
NASA is poised to send Lucy, its first spacecraft to study Jupiter’s Trojan asteroids, to glean new insights into the solar system’s formation 4.5 billion years ago, says the space agency
NASA launched a first-of-its kind mission on Saturday to study Jupiter’s Trojan asteroids, two large clusters of space rocks that scientists believe are remnants of primordial material that formed the solar system’s outer planets.
The space probe, dubbed Lucy and packed inside a special cargo capsule, lifted off on schedule from Cape Canaveral Air Force Station in Florida at 5:34 a.m. EDT (0934 GMT), NASA said. It was carried aloft by an Atlas V rocket from United Launch Alliance (UAL), a joint venture of Boeing Co and Lockheed Martin Corp.
Lucy’s mission is a 12-year expedition to study a record number of asteroids. It will be the first to explore the Trojans, thousands of rocky objects orbiting the sun in two swarms – one ahead of the path of giant gas planet Jupiter and one behind it.
The largest known Trojan asteroids, named for the warriors of Greek mythology, are believed to measure as much as 225 kilometers (140 miles) in diameter.
Scientists hope Lucy’s close-up fly-by of seven Trojans will yield new clues to how the solar system’s planets came to be formed some 4.5 billion years ago and what shaped their present configuration.
Believed to be rich in carbon compounds, the asteroids may even provide new insights into the origin of organic materials and life on Earth, NASA said.
“The Trojan asteroids are leftovers from the early days of our solar system, effectively the fossils of planet formation,” principal mission investigator Harold Levison of the Southwest Research Institute in Boulder, Colorado, was quoted by NASA as saying.
No other single science mission has been designed to visit as many different objects independently orbiting the sun in the history of space exploration, NASA said.
As well as the Trojans, Lucy will do a fly-by of an asteroid in the solar system’s main asteroid belt, called DonaldJohanson in honor of the lead discoverer of the fossilized human ancestor known as Lucy, from which the NASA mission takes its name. The Lucy fossil, unearthed in Ethiopia in 1974, was in turn named for the Beatles hit “Lucy in the Sky with Diamonds.”
Lucy the asteroid probe will make spaceflight history in another way. Following a route that circles back to Earth three times for gravitational assists, it will be the first spacecraft ever to return to Earth’s vicinity from the outer solar system, according to NASA.
The probe will use rocket thrusters to maneuver in space and two rounded solar arrays, each the width of a school bus, to recharge batteries that will power the instruments contained in the much smaller central body of the spacecraft.
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