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An international research team, with the participation of the Niels Bohr Institute of the University of Copenhagen, found the same type of interstellar dust that we know from the Milky Way in a distant galaxy to 11 billion light years from Earth. This type of dust has been found to be rare in other galaxies and the new discovery plays an important role in understanding what it takes for this particular type of interstellar dust to form.
The discovery of the persistence. On the left, an image of the so-called Pan-STARRS telescope in Hawaii taken before the explosion. On the right, an image of the same part of the sky taken with the Nordic Optical Telescope a few minutes after the recording of the explosion by the satellite Swift.
Galaxies are complex structures composed of many individual parts, such as stars, gases. , dust and dark matter. Even though dust is only a small part of the total amount of matter in a galaxy, it plays a major role in star formation and the way in which starlight escapes galaxies. The dust grains can both absorb and disperse the light. The dust particles also play a decisive role in the formation of the planets and therefore also for the understanding of our own existence on Earth.
How do you measure dust at 11 billion light years?
The dust in the galaxies of small grains of carbon, silicon, iron, aluminum and other heavier elements. The Milky Way has a very high content of carbon dust, which has proved very rare in other galaxies. But now, a similar type of dust has been found in some very distant galaxies that researchers have been able to study using light gamma-ray bursts.
Gamma-ray bursts come from mbadive stars that explode when the fuel in its core is exhausted. The explosion causes dying stars to emit powerful flashes of light that astronomers can use to badyze what makes up galaxies. Specifically, they can measure the elemental content and badyze their path to the properties of dust properties by examining the light that escapes galaxies.
Carbon dust is recorded in measurements as a "dust hump", that is, a high dust value with said composition. This hump of ultraviolet dust has now been detected in a burst of gamma rays, which has been named GRB180325A and the result has just been accepted for publication in the journal Astrophysical Journal Letters. The main author is Tayyaba Zafar, who has completed his Ph.D. studies at the Niels Bohr Institute in Copenhagen and is currently working at the Australian Angle Observatory in Australia. Several other NBI researchers are co-authors of the article
Collaboration between Observatories
The GRB180325A was detected by the Neil Gehrel Swift Observatory (NASA) on March 28, 2018. Swift is a satellite mission that detects gamma rays. dying stars. When such a detection of the satellite strikes astronomers, an eventful period begins. Astronomers are trying to observe this part of the sky as quickly as possible in order to obtain the crucial information that allow them to study inside the galaxy whose explosion is originating.
In this case Kasper Heintz, who did his master thesis at the Niels Bohr Institute and is now a PhD student at the University of Iceland, was on duty. He activated the Nordic Optical Telescope (NOT) in La Palma, where Professor Johan Fynbo of the Niels Bohr Institute was observing another project. The first light observations of the gamma burst were obtained only a few minutes after the discovery by Swift.
NOT's observations showed that the star had exploded in a galaxy with a red shift of 2.25, which means the light traveled about 11 billion light-years away. Observations immediately showed that the dust hump, known to the Milky Way, was present in this galaxy. The team then observed the explosion of gamma rays with the X-shooter spectrograph on the Very Large Telescope of the ESO (European Southern Observatory) on the Cerro Parbad in Chile. Overall, four spectra of afterglow of the gamma explosion were obtained – all with clear detection of dust.
"This is a fine example of how observations in space and in the world can work together." We must also thank the Carlsberg Foundation, without which Danish astronomy has no other role to play. Would have neither access to Very Large Telescope nor to NOT, "explains Professor Johan Fynbo.
" Our spectra show that the presence of atomic carbon seems to be a requirement for the dust that causes the formation of dust ", explains Kasper Heintz.
The dust hump has already been observed in the observation of four other gamma-ray bursts, the last of which
"Other observations of this type will allow us to find more galaxies with this bump of dust and thus perform a more systematic study of the similarities and differences in the composition of dust throughout the history of the United Kingdom and in galaxies with different properties ", explains Dr. Tayyaba Zafar
Scientific publication: T. Zafar and 28 co-authors, "The 2175 A extinction function in the optical remanence spectrum of GRB 180325A at z = 2.25" , 2018, letters from the astrophysical journal (ApJL), accepted.
Related Links
Faculty of Science – University of Copenhagen
Stellar Chemistry, the Universe and All Elements
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Magnetic field of the remains of SN 1987A observed [19659029] Toronto, Canada (SPX) Jul 02, 2018
For the first time, astronomers have directly observed magnetism in one of the most studied objects of astronomy: the remains of Supernova 1987A (SN 1987A), a dying star appeared in our skies years ago.
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"The magnetism we detected is about 50,000 times weaker than a refrigerator magnet," … read more
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