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    galaxy evolution tagged posts

    The Secrets of 3000 Galaxies laid Bare

    February 3, 2021, Categories  Astronomy/Space

    A/Prof Julia Bryant from the University of Sydney inside the SAMI instrument at the top end of the Anglo Australian Telescope
    Credit: Scott Croom/University of Sydney

    Shedding light on the evolution of the Universe. The complex mechanics determining how galaxies spin, grow, cluster and die have been revealed following the release of all the data gathered during a massive seven-year Australian-led astronomy research project.

    The scientists observed 13 galaxies at a time, building to a total of 3068, using a custom-built instrument called the Sydney-AAO Multi-Object Integral-Field Spectrograph (SAMI), connected to the 4-metre Anglo-Australian Telescope (AAT) at Siding Spring Observatory in New South Wales. The telescope is operated by the Australian National University.

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    How Galaxies Die: New insights into the Quenching of Star Formation

    July 18, 2020, Categories  Astronomy/Space

    galaxies-graph-500.jpg
    A new theory explains how black holes grow as a function of galaxy mass and eventually quench star formation in their host galaxies. The images on this graph, taken by the Sloan Digital Sky Survey, are of nearby galaxies at the present era chosen to represent galaxy evolution. The graph shows how the evolution of small, dense galaxies differs from that of larger, more diffuse galaxies. The denser galaxies have larger black holes for their mass and therefore quench sooner, at a lower mass, whereas the more diffuse galaxies have smaller black holes for their mass and must grow more before quenching occurs. See larger image. (Credit: Sandra Faber/Sofia Quiros/SDSS)

    Astronomers studying galaxy evolution have long struggled to understand what causes star formation to shut down in massive ga...

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    Galaxy Blazes with New Stars born from close encounter

    May 19, 2019, Categories  Astronomy/Space

    New image of irregular galaxy NGC 4485 captured by Hubble’s Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS).
    Credit: NASA and ESA; Acknowledgment: T. Roberts (Durham University, UK), D. Calzetti (University of Massachusetts) and the LEGUS Team, R. Tully (University of Hawaii), and R. Chandar (University of Toledo)

    The irregular galaxy NGC 4485 shows all the signs of having been involved in a hit-and-run accident with a bypassing galaxy. Rather than destroying the galaxy, the chance encounter is spawning a new generation of stars, and presumably planets.

    The right side of the galaxy is ablaze with star formation, shown in the plethora of young blue stars and star-incubating pinkish nebulas. The left side, however, looks intact...

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    Lightening up Dark Galaxies

    May 24, 2018, Categories  Astronomy/Space

    One of the new dark-galaxy candidates, identified through a combination of spectral information (left) and images reflecting the emission of gas (middle) and stars (right). The position of the dark-galaxy candidate is marked by the red circle. Credit: R. A. Marino / MUSE

    One of the new dark-galaxy candidates, identified through a combination of spectral information (left) and images reflecting the emission of gas (middle) and stars (right). The position of the dark-galaxy candidate is marked by the red circle. Credit: R. A. Marino / MUSE

    The identification of at least six candidates for dark galaxies could help filling an important gap in our understanding of galaxy evolution. Dark galaxies have a few (if any) stars in them and are, for that reason, notoriously difficult to detect with current instruments.

    Despite substantial progress over the past half a century in understanding of how galaxies form, important open questions remain regarding how precisely the diffuse gas known as the ‘intergalactic medium’ is converted into stars...

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