Tag Archives: #jet

Gigantic Jet Spied From Black Hole in Early Universe (Astronomy)

Astronomers have discovered evidence for an extraordinarily long jet of particles from a supermassive black hole in the early Universe, using NASA’s Chandra X-ray Observatory.

If confirmed, it would be the most distant supermassive black hole with a jet detected in X-rays, coming from a galaxy about 12.7 billion light years from Earth. It may help explain how the biggest black holes formed at a very early time in the Universe’s history.

The source of the jet is a quasar — a rapidly growing supermassive black hole — named PSO J352.4034-15.3373 (PJ352-15 for short), which sits at the center of a young galaxy. It is one of the two most powerful quasars detected in radio waves in the first billion years after the Big Bang, and is about a billion times more massive than the Sun.

How are supermassive black holes able to grow so quickly to reach such an enormous mass in this early epoch of the Universe? This is one of the key questions in astronomy today.

Despite their powerful gravity and fearsome reputation, black holes do not inevitably pull in everything that approaches close to them. Material orbiting around a black hole in a disk needs to lose speed and energy before it can fall farther inwards to cross the so-called event horizon, the point of no return. Magnetic fields can cause a braking effect on the disk as they power a jet, which is one key way for material in the disk to lose energy and, therefore, enhance the rate of growth of black holes.

“If a playground merry-go-round is moving too fast, it’s hard for a child to move towards the center, so someone or something needs to slow the ride down,” said Thomas Connor of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif., who led the study. “Around supermassive black holes, we think jets can take enough energy away so material can fall inward and the black hole can grow.”

Astronomers needed to observe PJ352-15 for a total of three days using the sharp vision of Chandra to detect evidence for the X-ray jet. X-ray emission was detected about 160,000 light years away from the quasar along the same direction as much shorter jets seen in radio waves. By comparison, the entire Milky Way spans about 100,000 light years.

PJ352-15 breaks a couple of different astronomical records. First, the longest jet previously observed from the first billion years after the Big Bang was only about 5,000 light years in length, corresponding to the radio observations of PJ352-15. Second, PJ352-15 is about 300 million light years farther away than the most distant X-ray jet recorded before it.

“The length of this jet is significant because it means that the supermassive black hole powering it has been growing for a considerable period of time,” said co-author Eduardo Bañados of the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany. “This result underscores how X-ray studies of distant quasars provide a critical way to study the growth of the most distant supermassive black holes.”

The light detected from this jet was emitted when the Universe was only 0.98 billion years old, less than a tenth of its present age. At this point, the intensity of the cosmic microwave background radiation (CMB) left over from the Big Bang was much greater than it is today.

As the electrons in the jet fly away from the black hole at close to the speed of light, they move through and collide with photons making up the CMB radiation, boosting the energy of the photons up into the X-ray range to be detected by Chandra. In this scenario, the X-rays are significantly boosted in brightness compared to radio waves. This agrees with the observation that the large X-ray jet feature has no associated radio emission.

“Our result shows that X-ray observations can be one of the best ways to study quasars with jets in the early Universe,” said co-author Daniel Stern, also of JPL. “Or to put it another way, X-ray observations in the future may be the key to unlocking the secrets of our cosmic past.”

A paper describing these results has been accepted for publication in The Astrophysical Journal and a preprint is available online. The other co-authors of the paper are Chris Carilli (NRAO, Socorro, New Mexico); Andrew Fabian (University of Cambridge, UK); Emmanuel Momjian (NRAO); Sofía Rojas-Ruiz (MPIA); Roberto Decarli (INAF, Bologna, Italy); Emanuele Paolo Farina (Max Planck Institute for Astrophysics, Garching, Germany); Chiara Mazzucchelli (ESO, Chile); Hannah P. Earnshaw (Caltech, Pasadena, California).

NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science from Cambridge Massachusetts and flight operations from Burlington, Massachusetts.

Featured image: Illustration of supernova 1987 A: X-ray: NASA/CXO/JPL/T. Connor; Optical: Gemini/NOIRLab/NSF/AURA;
Infrared: W.M. Keck Observatory; Illustration: NASA/CXC/M.Weiss
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Reference: Thomas Connor, Eduardo Bañados, Daniel Stern, Chris Carilli, Andrew Fabian, Emmanuel Momjian, Sofía Rojas-Ruiz, Roberto Decarli, Emanuele Paolo Farina, Chiara Mazzucchelli, Hannah P. Earnshaw, “Enhanced X-ray Emission from the Most Radio-Powerful Quasar in the Universe’s First Billion Years”, pp. 1-16, ArXiv, 2021. https://arxiv.org/abs/2103.03879


Provided by Chandra X-ray Observatory

Insight-HXMT Discovers Closest High-Speed Jet To Black Hole (Astronomy)

Insight-HXMT, China’s first space X-ray astronomical satellite, has discovered a low-frequency quasi-periodic oscillation (QPO) above 200 kiloelectron volts (keV) in a black hole binary, making it the highest energy low-frequency QPO ever found. The scientists also found that the QPO originated from the precession of a relativistic jet (high-speed outward-moving plasma stream) near the event horizon of the black hole. These discoveries have important implications for resolving the long-running debate about the physical origin of low-frequency QPOs.

Insight-HXMT discovers QPO generated in the closest jet to the black hole. Credit: IHEP

Low-frequency QPOs, discovered in the 1980s, are a common observational timing feature in transient black hole binaries. They are quasi-periodic, but not precisely periodic, modulations in light curves. For more than 30 years, the origin of low-frequency QPOs was not understood. The two most popular models explaining their origin are: 1) the oscillations are caused by the instability of the accretion disk when matter rotates around and finally falls into the black hole; and 2) the quasi-periodic X-ray modulations are produced by the oscillation or precession of the coronal X-ray emitting region close to the black hole.

Before the era of Insight-HXMT, X-ray satellites could only detect and study low-frequency QPOs below 30 keV; thus, it was difficult to test these models. Insight-HXMT, in contrast, has a wide effective energy range of 1-250 keV and has the largest effective area above 30 keV. Therefore, after Insight-HXMT was launched, scientists expected it would detect rich low-frequency QPOs above 30 keV, and thus be able to fully test previous models.

The new black hole X-ray binary MAXI J1820+070, consisting of a black hole of several solar masses and a companion star, started to undergo an outburst on March 11, 2018. It has been one of the brightest X-ray sources in the sky for a long time. Insight-HXMT quickly responded and performed high-cadence pointing observations on this source for several months, accumulating a huge amount of observational data.

Based on these data, the scientists found that the low-frequency QPO of MAXI J1820+070 appeared in a wide energy range and its maximum detection energy exceeded 200 keV, which is almost an order of magnitude higher than previous QPOs observed by other telescopes, indicating that the QPO could not come from the thermal radiation region of the accretion disk. Further studies revealed that the frequency and variability amplitude of the QPO are energy independent and the high-energy QPO precedes the low-energy one.

These results unambiguously conflicted with most currently existing models. Therefore, the scientists proposed that the low-frequency QPO was produced by the precession of a jet near the black hole’s event horizon; the precession was probably caused by the frame-dragging effect of general relativity, generated by the rotation of the black hole.

Jets are high-speed matter streams moving at close to the speed of light. Plenty of jets have been observed in black hole binaries and distant quasars hosting supermassive black holes (i.e., those of millions to tens of billions of solar masses) in the radio, optical and X-ray bands. Jets are an important observational characteristic of black hole systems, and are the main means by which black holes influence the surrounding environment via feedback when swallowing nearby matter.

However, these jets are far from black holes. They are usually located at a distance of more than a million times the black hole’s event horizon. At such a long distance, the black hole’s gravitational force actually has no effect. Therefore, it is unclear where these jets are generated, how far they are from the black holes, how they can escape from the strong gravitational field of the black holes and how they are accelerated to a speed close to the speed of light.

Insight-HXMT’s discovery is particularly important because it’s the first time a jet has been found only hundreds of kilometers away from a black hole (i.e., several times the black hole’s event horizon). As the closest relativistic jet observed in a black hole so far, the finding is of great significance for studying the relativistic effects, dynamical processes and radiation mechanisms.

References: Ma, X., Tao, L., Zhang, S. et al. Discovery of oscillations above 200 keV in a black hole X-ray binary with Insight-HXMT. Nat Astron (2020). https://doi.org/10.1038/s41550-020-1192-2 link: https://www.nature.com/articles/s41550-020-1192-2

TXS 0128+554 Is Now A Youngest Gamma-Ray-Emitting Active Galactic Nucleus with Episodic Jet Activity (Astronomy)

In this image, made with the National Science Foundation’s Very Long Baseline Array (VLBA), young, radio-emitting jets of material emerge from the core of an elliptical galaxy some 500 million light-years away in the constellation Cassiopeia, anchored by a supermassive black hole around 1 billion times the Sun’s mass. After NASA’s Fermi Gamma-ray Space Telescope detected high-energy gamma rays coming from the object, scientists used the VLBA to make high-resolution images of the galaxy, dubbed TXS 0128+554.

Credit: Lister et al.; Sophia Dagnello, NRAO/AUI/NSF

This image is a composite of six VLBA images made at observing frequencies ranging from 2.2 GigaHertz (GHz) to 22.2 GHz. The broad lobes on either side of the bright core are the result of jet activity that began roughly 80 years ago. The gap between these lobes and the central region indicates, the scientists said, that the jet activity stopped sometime after that, then resumed about 10 years ago.

These are among the youngest known jets in such systems, and only a handful are known to emit gamma-rays.

The bright edges of the lobes are where the ejected material, moving at about a third the speed of light, impacted material within the galaxy. The bright emitting areas total about 35 light-years across, and are at the core of the galaxy, where a supermassive black hole about one million times the mass of the Sun resides.

The predicted γ-ray emission from the lobes, based on an inverse Compton-emitting cocoon model, is three orders of magnitude below the observed Fermi-LAT flux. A comparison to other Fermi-detected and non-Fermi-detected CSOs with redshift z < 0.1 indicates that the γ-ray emission likely originates in the inner jet/core region, and that nearby, recently launched AGN jets are primary candidates for detection by the Fermi-LAT instrument.


References: M. L. Lister, D. C. Homan, Y. Y. Kovalev, S. Mandal, A. B. Pushkarev, and A. Siemiginowska, “TXS 0128+554: A Young Gamma-Ray-emitting Active Galactic Nucleus with Episodic Jet Activity”, The Astrophysical Journal, Volume 899, Number 2, 2020 DOI: 10.3847/1538-4357/aba18d link: https://iopscience.iop.org/article/10.3847/1538-4357/aba18d

The Government Mind Control Conspiracy Theory Of Chemtrails (Chemistry)

When you see a plane in the sky, you probably notice the white tails trailing behind it. Usually, the tails quickly dissipate, but some people think they stick around longer than is natural.

Are these tails simply harmless contrails (the condensation created in the air from jet exhaust), or are they the more sinister “chemtrails”? Many believers in the chemtrails conspiracy theory think the trails are loaded with unknown chemicals supplied by the government to brainwash the minds of civilians. Other “chemmies” believe the chemicals poison people to “weed out” the ill and elderly. Another idea is that chemtrails are used to worsen global warming. Scientists reject these theories, maintaining that the scientific evidence behind contrails leaves little room for mystery.

Stuff they don’t want you to know- Chemtrials