Galaxies

Blogs about galaxies, singles ones on in clusters

The cosmic wave in red and blue, with stars above the galactic disk in red and the ones below it in blue

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An article published in the journal “Astronomy and Astrophysics” reports the results of a study that provides evidence that a sort of giant cosmic wave is crossing the Milky Way, propagating from the center outward from the galactic disk, causing a corrugation. A team of researchers led by Eloisa Poggio of the Italian National Institute for Astrophysics used data collected by ESA’s Gaia space probe to map the motions of thousands of young giant stars and Cepheids within the corrugation, reconstructing the wave that generates them. The cause may be the aftermath of an ancient collision with a dwarf galaxy, but follow-up studies are needed to assess this and other possible explanations.

The Magellanic Clouds as seen by the Gaia space probe (Image ESA)

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An article published in “The Astrophysical Journal Letters” reports the results of a study of the Small Magellanic Cloud that shows how this dwarf galaxy is undergoing distortions in its shape due to various gravitational influences. Satoya Nakano and Kengo Tachihara of Nagoya University, Japan, used data collected by ESA’s Gaia space probe together with information on Cepheid stars collected by the OGLE (Optical Gravitational Lensing Experiment) project. This allowed them to determine the distances of 4,236 Cepheids and the anomalies in their motions. The conclusion is that the Small Magellanic Cloud is undergoing a gravitational influence from the Large Magellanic Cloud and another as yet unknown source.

The galaxy JADES-GS-z13-1 (the red circle in the center) as seen by the James Webb Space Telescope (Image ESA/Webb, NASA, STScI, CSA, JADES Collaboration, Brant Robertson (UC Santa Cruz), Ben Johnson (CfA), Sandro Tacchella (Cambridge), Phill Cargile (CfA), J. Witstok, P. Jakobsen, A. Pagan (STScI), M. Zamani (ESA/Webb))

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An article published in the journal “Nature” reports the results of observations of the primordial galaxy cataloged as JADES-GS-z13-1. A team of researchers used the James Webb Space Telescope to examine this galaxy, estimating that it dates back to about 330 million years after the Big Bang. The surprise came from spectroscopic analyses with so-called Lyman-alpha radiation, emitted in the ultraviolet by hydrogen in specific circumstances, because it was much stronger than would be expected from a galaxy of that era.

Herbig-Haro 49/50 (NIRCam and MIRI Image, annotated)

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An image captured by the James Webb Space Telescope shows Herbig-Haro 49/50, or simply HH 49/50, a type of nebula associated with star formation. The Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) instruments were used in combination to observe infrared details of the outflows whose shape led to the object being nicknamed the Cosmic Tornado. For years, astronomers have wondered what the object they could barely see in images obtained with other instruments at the “tip of the tornado” was, and Webb helped them realize that it’s a spiral galaxy that is far more distant.

The Small Magellanic Cloud and the molecular coulds subject of this study

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An article published in “The Astrophysical Journal” reports a study of 17 molecular clouds in the Small Magellanic Cloud, one of the Milky Way’s satellite dwarf galaxies. A team of researchers led by Kazuki Tokuda, a postdoctoral researcher at Kyushu University, Japan, examined high-resolution images captured using the ALMA radio telescope to obtain information on their characteristics. The examination showed that 40% of those clouds had a more diffused gas, with fluffy structures. The others were classic molecular clouds with a filamentary structure that are also found in the Milky Way. This difference was attributed to the scarcity of elements heavier than hydrogen and helium in the Small Magellanic Cloud, a situation similar to that of the early universe.