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Astronomers May Have Found a 'Missing Link' Black Hole Because It Ate a Star – ScienceAlert

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Black holes are sneaky. They lurk out there in the dark, not giving off any detectable radiation, making them very hard to find. But they have a weakness: they’re extremely messy eaters. And this propensity has allowed astronomers to zero in on something elusive: the “missing link” middleweight black hole.

A colossal X-ray flare observed in 2006 was suspected to be the spillage from an intermediate-mass black hole – 50,000 times the mass of the Sun – as it tore apart and devoured a star. By eliminating a major competing hypothesis, researchers are now confident they’re on the right track, and it’s a pretty big deal.

Black holes are mysterious at the best of times. Because they emit no light, we can’t see them, and we have to measure their properties based on the effect they have on the stuff around them – whether it’s orbiting objects, or stuff they’re actually accreting, a process that generates a great deal of heat and light.

But intermediate-mass black holes up the mystery ante. Because while we’ve found really titchy stellar-mass black holes (up to 100 times the mass of the Sun) and really chonky supermassive black holes (over 100,000 times the mass of the Sun, although they can get much bigger), the weight class in between has proven extremely elusive.

We’ve had hints that intermediate-mass black holes are out there, but nothing conclusive. This new paper, according to its authors, is the best evidence yet.

That evidence hinges on a huge X-ray flare called 3XMM J215022.4−055108 (or J2150−0551 for short). While the light show had been going for three years already, the flare was first detected in 2006 by two powerful X-ray space telescopes –  NASA’s Chandra X-ray Observatory and the European Space Agency’s X-ray Multi-Mirror Mission (XMM-Newton).

(NASA, ESA, and D. Lin (University of New Hampshire)

In 2018, physicist and astronomer Dacheng Lin of the University of New Hampshire and colleagues published a paper based on observations from these telescopes. The flare, they concluded, was likely the radiation blasted out as an intermediate-mass black hole devoured a star.

Now Lin and his team have obtained and analysed new multi-wavelength observations from XMM Newton and the Hubble Space Telescope. And they’re more certain than ever that this is what caused the flare.

“Intermediate-mass black holes are very elusive objects, and so it is critical to carefully consider and rule out alternative explanations for each candidate,” Lin said. “That is what Hubble has allowed us to do for our candidate.”

One of the curious things about J2150−0551 was its location – not in the centre of a galaxy, where you normally find large black holes tearing apart stars. In fact, it seemed to come from a star cluster on the outskirts of a lenticular galaxy 800 million light-years away.

This is consistent with one of the formation models for intermediate-mass black holes that also explains why they’re so tricky to find.

A 2004 paper proposed that the gravity of a dense star cluster could cause the stars inside it to fall towards the cluster’s centre, forming a star as massive as thousands of Suns. This then would collapse under its own weight, forming an intermediate-mass black hole.

But, because it’s extremely hard to resolve individual stars outside the Milky Way, never mind tracking their orbits, black holes outside the Milky Way are only detectable when material, such as a star or a gas cloud, is actively falling into them.

By the time one of these star clusters had created a black hole, it would have cleared the area within its gravitational reach, meaning there’s no material left in its vicinity for it to devour, except for the rare and occasional stray star. This is what astronomers think J2150−0551 was caused by.

And there was still a possibility that J2150−0551 was something else – a neutron star inside the Milky Way that was cooling after being heated during an accretion outburst – slurping down material from another star. An accretion outburst large enough to cause this heating in a neutron star had not been detected in an all-sky survey that should have picked it up, but we needed a more conclusive ruling.

Hubble was pointed at the patch of sky in which J2150−0551 was seen to obtain deep, high-resolution imaging to confirm its location. These observations confirmed that the X-ray glow had not emanated from the Milky Way, but the star cluster 800 million light-years away.

Meanwhile, XMM Newton obtained more X-ray observations.

“Adding further X-ray observations allowed us to understand the total energy output,” said astronomer Natalie Webb of the Université de Toulouse in France. “This helps us to understand the type of star that was disrupted by the black hole.”

These observations led the researchers to conclude that the flare was caused by an intermediate-mass black hole as it captured, shredded and accreted a small, main-sequence star around a third of our Sun’s mass, and about 40 percent of its size.

They also found that the star cluster itself could be the core of a dwarf galaxy, stripped of most of its material due to gravitational interactions with the larger galaxy it borders.

Importantly, the finding reaffirms that star clusters orbiting more massive galaxies could be a prime location for finding these elusive intermediate-mass black holes.

The research has been published in The Astrophysical Journal Letters.

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Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

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More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.

That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.

“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”

The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.

Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.

Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.

Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.

Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.

Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.

“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”

The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.

North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.

Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”

Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.

Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.

For Dello, the “fingerprints of climate change” were clear.

“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”

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Follow AP’s climate coverage at https://apnews.com/hub/climate

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Follow Seth Borenstein on Twitter at @borenbears

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Associated Press climate and environmental coverage receives support from several private foundations. See more about AP’s climate initiative here. The AP is solely responsible for all content.

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‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.

On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.

They call it “Big Sam.”

The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.

It didn’t die alone.

“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.

She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”

“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.

The head alone, she said, is about the size of a baby elephant.

The discovery was a long time coming.

The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.

“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.

When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”

“It contains about 100 to 300 bones per square metre,” she said.

Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.

About a year ago, they found the second adult: Big Sam.

Bamforth said both dinosaurs are believed to have been the elders in the herd.

“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.

“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”

The genders of the two adults are unknown.

Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.

The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.

She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.

“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.

“It’s pretty exciting.”

This report by The Canadian Press was first published Sept. 25, 2024.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

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