Simüle kara delik jetleri bu animasyonda dönüyor ve geçiyor. Işık hızına yakın hareket eden parçacıkları içeren jetler turuncu, pembe ve mor renkte görünürken, galaksinin çevresi – yıldızlar ve gaz bulutları – yeşil ve sarı olarak gösteriliyor. Zayıf jetler bu ortamda hareket ettikçe yön değiştirebilir, bölünebilir ve hatta bastırılabilir. Gökbilimciler zayıf jetleri doğrudan gözlemlemekte zorlandıklarından, bu simülasyonlar onları daha kolay tespit edilen galaktik özelliklere bağlar. Kredi: NASA’nın Goddard Uzay Uçuş Merkezi/R. Tanner ve K. Weaver

Milky Way galaxy, and can weigh millions to billions of times the mass of the Sun. To perform the highly complex simulations the scientists leveraged the Discover supercomputer at the NASA Center for Climate Simulation (NCCS).

As jets and winds flow out from these active galactic nuclei (AGN), they “regulate the gas in the center of the galaxy and affect things like the star-formation rate and how the gas mixes with the surrounding galactic environment,” explained study lead Ryan Tanner, a postdoc in NASA Goddard’s X-ray Astrophysics Laboratory.

NASA İklim Simülasyon Merkezi (NCCS) Discover süper bilgisayarında gerçekleştirilen yeni simülasyonlar, bir galaksinin canavarı tarafından üretilen daha zayıf, düşük parlaklıktaki jetlerin ne kadar olduğunu gösteriyor.[{” attribute=””>black hole interact with their galactic environment. Because these jets are more difficult to detect, the simulations help astronomers link these interactions to features they can observe, such as various gas motions and optical and X-ray emissions. Credit: NASA’s Goddard Space Flight Center

“For our simulations, we focused on less-studied, low-luminosity jets and how they determine the evolution of their host galaxies,” Tanner said. He collaborated with X-ray Astrophysics Laboratory astrophysicist Kimberly Weaver on the computational study, which was published earlier this year in The Astronomical Journal.

Observational evidence for jets and other AGN outflows first came from radio telescopes and later NASA and European Space Agency X-ray telescopes. Over the past 30 to 40 years, astronomers including Weaver have pieced together an explanation of their origin by connecting optical, radio, ultraviolet, and X-ray observations (see the next image below).

Diversity of Black Hole Jets

These images show the diversity of black hole jets. Left: NGC 1068, one of the nearest and brightest galaxies (green and red) with a rapidly growing supermassive black hole, powers a jet (blue) much smaller than the galaxy itself. Credit: NASA/CXC/MIT/C.Canizares, D.Evans et al. (X-ray); NASA/STScI (optical); and NSF/NRAO/VLA (radio). Right: The galaxy
Centaurus A reveals particle jets extending far above and below the galaxy’s disk. Credit: ESO/WFI (optical); MPIfR/ESO/APEX/A.Weiss et al. (submillimeter); and NASA/CXC/CfA/R. Kraft et al. (X-ray)

“High-luminosity jets are easier to find because they create massive structures that can be seen in radio observations,” Tanner explained. “Low-luminosity jets are challenging to study observationally, so the astronomy community does not understand them as well.”

Enter NASA supercomputer-enabled simulations. For realistic starting conditions, Tanner and Weaver used the total mass of a hypothetical galaxy about the size of the Milky Way. For the gas distribution and other AGN properties, they looked to spiral galaxies such as NGC 1386, NGC 3079, and NGC 4945.

Discover Supercomputer

The black hole jet simulations were performed on the 127,232-core Discover supercomputer at the NCCS. Credit: NASA’s Goddard Space Flight Center Conceptual Image Lab

Tanner modified the Athena astrophysical hydrodynamics code to explore the impacts of the jets and gas on each other across 26,000 light-years of space, about half the radius of the Milky Way. From the full set of 100 simulations, the team selected 19 — which consumed 800,000 core hours on the NCCS Discover supercomputer — for publication.

“Being able to use NASA supercomputing resources allowed us to explore a much larger parameter space than if we had to use more modest resources,” Tanner said. “This led to uncovering important relationships that we could not discover with a more limited scope.”

Ryan Tanner and Kimberly Weaver

Study co-authors were Ryan Tanner and Kimberly Weaver, researchers in NASA Goddard’s X-ray Astrophysics Laboratory. Credit: NASA

The simulations uncovered two major properties of low-luminosity jets:

  • They interact with their host galaxy much more than high-luminosity jets.
  • They both affect and are affected by the interstellar medium within the galaxy, leading to a greater variety of shapes than high-luminosity jets.

Impact: These simulations demonstrate that interactions between jets and their host galaxies can explain regions of optical and X-ray emissions, as well as a variety of gas motions, observed in some active galactic nuclei (AGN).

“We have demonstrated the method by which the AGN impacts its galaxy and creates the physical features, such as shocks in the interstellar medium, that we have observed for about 30 years,” Weaver said. “These results compare well with optical and X-ray observations. I was surprised at how well theory matches observations and addresses longstanding questions I have had about AGN that I studied as a graduate student, like NGC 1386! And now we can expand to larger samples.”

Bu görselleştirme, yıldızlararası moleküler bulutlar (mavi ve yeşil) tarafından bozulan aktif bir galaksinin jetinin (turuncu ve mor) karmaşık yapısını göstermektedir. Jet, galaksinin merkez düzlemine 30 derecelik bir açıyla yönlendirildiğinden, galaksinin yıldızları ve gaz bulutları ile daha yoğun etkileşim, jetin ikiye bölünmesine neden oldu. Katkıda Bulunma: Görselleştirme Ryan Tanner ve Kim Weaver, NASA Goddard

Referans: Ryan Tanner ve Kimberly A. Weaver tarafından yazılan “AGN-driven Galactic Outflow Morphology and Content Simulations of AGN-driven Galactic Outflow Morphology and Content”, 17 Şubat 2022, Astronomi Dergisi.
DOI: 10.3847/1538-3881/ac4d23



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