Astronomy

Forscher:innen der Universität zu Köln und der Masaryk-Universität in Brünn (Tschechien) haben den bislang schnellsten Stern entdeckt, der sich in kürzester Zeit um ein schwarzes Loch herum bewegt. Der Stern mit dem Namen S4716 umkreist in vier Jahren Sagittarius A*, das schwarze Loch im Zentrum unserer Milchstraße und erreicht dabei eine Geschwindigkeit von rund 8000 Kilometern pro Sekunde. S4716 kommt dem schwarzen Loch bis auf 100 AE (Astronomische Einheit) nahe – für astronomische Verhältnisse eine geringe Distanz. Eine AE entspricht 149.597.870 Kilometern. Die Studie wurde im Fachjournal The Astrophysical Journal veröffentlicht.

Pressemitteilung 

Zur Publikation:

https://doi.org/10.3847/1538-4357/ac752f

The SOFIA flying observatory is a joint U.S.-German project (NASA & DLR). Although the nominal German project share is "only" 20%, the German side provides almost 50% of the instruments currently in operation with GREAT (German REceiver for Astronomy at Terahertz Frequencies, jointly operated by MPIfR and I. Phys. Inst. of Cologne Univ.), FIFI-LS (Field-Imaging Far-Infrared Line-Spectrometer) and FPI+ (Focal Plane Imager Plus). This is reflected by the fact that between 2009 and 2019, 45% of the peer-reviewed SOFIA publications are based on observations with these instruments. These include publications in the renowned science journal "Nature" such as the first detection of helium hydride (HeH⁺) - the first type of molecule in the universe - with the German GREAT instrument. With the same instrument, in addition to observations of astronomical objects, researchers can in parallel determine the concentration of atomic oxygen in the Earth's mesosphere and lower thermosphere, which is important in these layers for atmospheric models and climate change predictions (SOFIA/USRA Status Report report "Future & Prospects", 52 pages, 34 MB pdf file, April 13, 2022).

 >> more

The SOFIA flying observatory is a joint U.S.-German project (NASA & DLR). Although the nominal German project share is "only" 20%, the German side provides almost 50% of the instruments currently in operation with GREAT (German REceiver for Astronomy at Terahertz Frequencies, jointly operated by MPIfR and I. Phys. Inst. of Cologne Univ.), FIFI-LS (Field-Imaging Far-Infrared Line-Spectrometer) and FPI+ (Focal Plane Imager Plus). This is reflected by the fact that between 2009 and 2019, 45% of the peer-reviewed SOFIA publications are based on observations with these instruments. These include publications in the renowned science journal "Nature" such as the first detection of helium hydride (HeH⁺) - the first type of molecule in the universe - with the German GREAT instrument. With the same instrument, in addition to observations of astronomical objects, researchers can in parallel determine the concentration of atomic oxygen in the Earth's mesosphere and lower thermosphere, which is important in these layers for atmospheric models and climate change predictions (SOFIA/USRA Status Report report "Future & Prospects", 52 pages, 34 MB pdf file, April 13, 2022).

 >> more

We showed that the fraction of [CII] - HII Region related emission varies a lot for any given line-of-sight, and it can be as high as 70% of the total observed[CII] emission. Those results were then used to predict the [N/H] elemental abundance in the GC (a value poorly constraint  in the GC). Our results showed that it should be much larger ~x7.5 than what is measured in the Galactic Disk, and nearly x2.3 larger than previous measurements int he Arched Filaments. 

To date, infrared interferometry at best achieved contrast ratios of a few times 10−4 on bright targets. GRAVITY, with its dual-field mode, is now capable of high contrast observations, enabling the direct observation of exoplanets. We demonstrate the technique on HR 8799, a young planetary system composed of four known giant exoplanets.

https://doi.org/10.1051/0004-6361/201935253

We measure for the first time the overall extent within which stars in distant galaxies were born. At all cosmic epochs, star formation in massive galaxies preferentially takes place in their central region, indicating that we are witnessing the final assembly of their stellar bulges. Few galaxies have a more compact star-forming extent, and all of them produce stars at a much higher rate than the average. This suggests a different mechanism triggering their star formation activities, such as the merger of two gas-rich disks.

https://doi.org/10.1051/0004-6361/201935178

We measure for the first time the overall extent within which stars in distant galaxies were born. At all cosmic epochs, star formation in massive galaxies preferentially takes place in their central region, indicating that we are witnessing the final assembly of their stellar bulges. Few galaxies have a more compact star-forming extent, and all of them produce stars at a much higher rate than the average. This suggests a different mechanism triggering their star formation activities, such as the merger of two gas-rich disks.

https://doi.org/10.1051/0004-6361/201935178

The IRAM/GISMO 2 millimeter survey in the COSMOS field provides a unique view on star formation at the time when the Universe was only two billion years old. It reveals a significant population of extreme galaxies. Compared to the Milky-Way, they are about three times more massive, and form about 1000 times more stars per year. The sheer existence of these galaxies, soon after the Big-Bang, challenges current galaxy formation models.

https://iopscience.iop.org/article/10.3847/1538-4357/ab1912

The IRAM/GISMO 2 millimeter survey in the COSMOS field provides a unique view on star formation at the time when the Universe was only two billion years old. It reveals a significant population of extreme galaxies. Compared to the Milky-Way, they are about three times more massive, and form about 1000 times more stars per year. The sheer existence of these galaxies, soon after the Big-Bang, challenges current galaxy formation models.

https://iopscience.iop.org/article/10.3847/1538-4357/ab1912

This article reports the interstellar detection of urea. The detection was made possible thanks to a new, sensitive spectral line survey carried out with ALMA toward the high-mass star-forming region Sgr B2(N).

https://arxiv.org/abs/1906.04614