ALMA tagged posts

The Structure of an Active Galactic Nucleus

The structure of an active galactic nucleus

A Hubble image of the superluminous merging galaxy Arp220. Astronomers have measured structures only a hundreds of light-years in size around the two supermassive black holes in the nuclear region, as well as evidece for an outflow. Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University

The nuclei of most galaxies host supermassive black holes containing millions to billions of solar-masses of material. The immediate environments of these black holes typically include a tori of dust and gas and, as material falls toward the black hole, the gas radiates copiously at all wavelengths...

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Galaxy Growth in a Massive Halo in the 1st Billion years of Cosmic history

The Aurora Australis, or Southern Lights, over the South Pole Telescope at NSF's Amundsen-Scott South Pole Station. Credit: Dr. Keith Vanderlinde, NSF

The Aurora Australis, or Southern Lights, over the South Pole Telescope at NSF’s Amundsen-Scott South Pole Station. Credit: Dr. Keith Vanderlinde, NSF

Observations of two galaxies made with ALMA radio telescope suggest that large galaxies formed faster than scientists had previously thought. The two galaxies, first discovered by the South Pole Telescope at NSF’s Amundsen-Scott South Pole Station in Antarctica, were massive and star-filled at a time when the cosmos was < 1B years old. The observation came as a surprise, considering astronomers had thought that the first galaxies, which formed just a few hundred million years after the Big Bang, were similar to today’s dwarf galaxies – collections of stars much smaller than the Milky Way...

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Another Close-by Planetary System?

This artist's impression shows how the newly discovered belts of dust around the closest star to the Solar System, Proxima Centauri, may look. ALMA observations revealed the glow coming from cold dust in a region between one to four times as far from Proxima Centauri as the Earth is from the Sun. The data also hint at the presence of an even cooler outer dust belt and indicate the presence of an elaborate planetary system. These structures are similar to the much larger belts in the Solar System and are also expected to be made from particles of rock and ice that failed to form planets. Note that this sketch is not to scale -- to make Proxima b clearly visible it has been shown further from the star and larger than it is in reality. Credit: ESO/M. Kornmesser

This artist’s impression shows how the newly discovered belts of dust around the closest star to the Solar System, Proxima Centauri, may look. ALMA observations revealed the glow coming from cold dust in a region between one to four times as far from Proxima Centauri as the Earth is from the Sun. The data also hint at the presence of an even cooler outer dust belt and indicate the presence of an elaborate planetary system. These structures are similar to the much larger belts in the Solar System and are also expected to be made from particles of rock and ice that failed to form planets. Note that this sketch is not to scale — to make Proxima b clearly visible it has been shown further from the star and larger than it is in reality. Credit: ESO/M. Kornmesser

ALMA discovers cold dust around ...

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Shedding Light on Galaxies’ Rotation Secrets

Image: . Angular Momentum of Early- and Late-type Galaxies: Nature or Nurture? The Astrophysical Journal, 2017; 843 (2): 105 DOI: 10.3847/1538-4357/aa7893

Image: . Angular Momentum of Early- and Late-type Galaxies: Nature or Nurture? The Astrophysical Journal, 2017; 843 (2): 105 DOI: 10.3847/1538-4357/aa7893

The dichotomy concerns the so-called angular momentum (per unit mass), that in physics is a measure of size and rotation velocity. Spiral galaxies are found to be strongly rotating, with an angular momentum higher by a factor of about 5 than ellipticals. What is the origin of such a difference? An international research team investigated the issue in a study just published in the Astrophysical Journal. The team was led by SISSA Ph.D. student JingJing Shi under the supervision of Prof. Andrea Lapi and Luigi Danese, and in collaboration with Prof. Huiyuan Wang from USTC (Hefei) and Dr. Claudia Mancuso from IRA-INAF (Bologna). The res...
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