- 3234 - GALAXIES - die too? - A single galaxy may contain billions of stars and their solar systems, all held together by the sheer force of gravity. But even galaxies die. After all of its star-forming gas runs out, and all of its stars have burned out, a galaxy dies. It will one day happen to the Milky Way, too. That day is some 5 billion years into our future. Probably should not have used “our”
------------------ 3234 - GALAXIES - die too?
- Until as late as, astronomers had never witnessed a distant galaxy”s death. However, recent observations by the Atacama Large Millimeter / submillimeter Array (ALMA) have given astronomers their first view of a large galactic system nearing its death.
-
- Astronomers observing some 100 galaxies in distant locations noticed something odd about galaxy ID2299. ALMA, the array of telescopes located in northern Chile caught a glimpse of ID2299 for a few minutes but researchers could see that the galaxy had a tail of gas that was being ejected from it. The gas is being ejected at a startling rate, the equivalent of 10,000 Suns a year. Additionally, it is removing 46 percent of the galaxy's total cold gas.
-
- The galaxy is located 9 billion light-years away from Earth, meaning that it existed at a time when the universe was merely 4.5 billion years old. The universe was formed 13.8 billion years ago. Star formation in galaxies then was at a much higher rate than it is today.
-
- Galaxy ID2299 is forming stars hundreds of times faster than our Milky Way, and therefore the gas that remained in the galaxy will quickly be consumed as more stars continue to be born.
-
- As a result, the galaxy will meet its final demise in just a few tens of million years. The galaxy's untimely death was brought on by the collision between two galaxies, which merged to form ID2299.
-
- The telltale sign that there had been a galactic collision was a "tidal tail." Tidal tails are an elongated stream of stars and gas that extend outwards from a merged galaxy after two galaxies have collided into each other to form one.
-
- Although scientists had previously suggested that these tidal tails form from the star formation process and activity of the blackholes at the center of the galaxy, the recent observations of ID2299 suggest that the tails of star-forming gas could also be the result of a galactic merger.
-
- By studying the relationship between the star-forming gas and the galaxy's eventual death, astronomers are hoping to understand how galaxies evolve over time until they stop giving birth to stars, and die.
-
- This massive starburst galaxy at z = 1.4 which is ejecting 46 ± 13% of its molecular gas mass at a startling rate of & 10, 000 Myr.
-
- A blackhole is a region of spacetime where the gravity is so powerful that not even light can escape them. They are created when massive stars die. The jets blast material out the poles at nearly the speed of light. Researchers obtained the highest resolution images yet of these eruptive jets as they blasted from a nearby blackhole.
-
- The new images suggest blackholes of different masses, ranging from three times the mass of the Sun to a billion solar masses, behave similarly.
-
- Centaurus A is a giant elliptical active galaxy 12 million light-years away from Earth. It is the nearest galaxy with a strong jet of plasma erupting from its center. This jet exists because the center is home to a blackhole weighing 55 million times the mass of the Sun.
-
- By pointing their radio telescopes at the center of Centaurus A, the scientists were able to zoom into as close as 0.6 lightyears away from the blackhole itself.
-
- A blackhole will launch a jet in one direction, and another in the opposite direction. Th
This is the first image of a blackhole and was taken in 2019. It shows the “ring of fire” that surrounds a blackhole’s event horizon.
-
- M87 sits at the center of the galaxy Messier 87, an elliptical galaxy located 55 million light-years away. The blackhole itself is weighing at 6.5 billion times the mass of the Sun.
-
- The analysis revealed that, although M87 and Centaurus A greatly vary in mass, their jets are quite similar. The study team found the geometry and other properties of both blackholes’ jets are pretty much the same, confirming massive black holes are simply scaled up versions of their not-so-massive counterparts.
-
-Black holes typically come in two sizes: Stellar-mass blackholes, which are five to ten times the mass of the Sun and Supermassive blackholes, which are millions or billions of times the mass of the Sun
-
- A blackhole feeds on its surrounding material, gobbling up nearby stars and other objects in order to grow in size. The amount of material swallowed by a blackhole largely depends on its environment.
-
- During their feeding frenzies, some matter, hot gas or dust, falls toward the center of the blackhole. It then shoots out in the form of jets, or two short beams of material, from outside the boundary that surrounds the blackhole. This boundary is known as the “event horizon“. These jets can sometimes reach the outside of the galaxy itself, traveling at nearly the speed of light.
-
- Astronomers are now working on capturing a video of the blackhole at the center of the Milky Way., Sagittarius A*. Ideally, the video will reveal movement taking place around the blackhole, giving scientists a better idea of its surrounding conditions.
-
- Very-long-baseline interferometry observations of active galactic nuclei at millimeter wavelengths have the power to reveal the launching and initial collimation region of extragalactic radio jets, down to 10–100 gravitational radii (rg≡GM/c2 ) scales in nearby sources
-
- . Centaurus A is the closest radio-loud source to Earth . It bridges the gap in mass and accretion rate between the supermassive blackholes in Messier 87 and our Galactic Center. A large southern declination of −43° has, however, prevented imaging of Centaurus A below a wavelength of 1 cm thus far.
-
- The millimetre image of the source obtained with the Event Horizon Telescope is at 228 GHz. Compared with previous observations , we image the jet of Centaurus A at a tenfold higher frequency and sixteen times sharper resolution and thereby probe sub-lightday structures.
-
- This reveals a highly collimated, asymmetrically edge-brightened jet as well as the fainter counterjet. We find that the source structure of Centaurus A resembles the jet in Messier 87 on 500 rg scales remarkably well ( rg≡GM/c2 ).
-
- Astronomers have identifed the location of Centaurus A’s SMBH with respect to its resolved jet core at a wavelength of 1.3 mm and conclude that the source’s event horizon shadow should be visible at terahertz frequencies. This location further supports the universal scale invariance of blackholes over a wide range of masses.
-
- July 26, 2021 GALAXIES - die too 3234
----------------------------------------------------------------------------------------
----- Comments appreciated and Pass it on to whomever is interested. ----
--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for copies or Index of all reviews
--- to: ------ jamesdetrick@comcast.net ------ “Jim Detrick” -----------
--------------------- --- Wednesday, July 28, 2021 ---------------------------
No comments:
Post a Comment