• Supermassive black hole caught hiding in

    From ScienceDaily@1:317/3 to All on Wed Feb 16 21:30:50 2022
    Supermassive black hole caught hiding in a ring of cosmic dust

    Date:
    February 16, 2022
    Source:
    ESO
    Summary:
    The European Southern Observatory's Very Large Telescope
    Interferometer (ESO's VLTI) has observed a cloud of cosmic dust at
    the centre of the galaxy Messier 77 that is hiding a supermassive
    black hole. The findings have confirmed predictions made around
    30 years ago and are giving astronomers new insight into "active
    galactic nuclei", some of the brightest and most enigmatic objects
    in the universe.



    FULL STORY ==========================================================================
    The European Southern Observatory's Very Large Telescope Interferometer
    (ESO's VLTI) has observed a cloud of cosmic dust at the centre of
    the galaxy Messier 77 that is hiding a supermassive black hole. The
    findings have confirmed predictions made around 30 years ago and are
    giving astronomers new insight into "active galactic nuclei," some of
    the brightest and most enigmatic objects in the universe.


    ========================================================================== Active galactic nuclei (AGNs) are extremely energetic sources powered by supermassive black holes and found at the centre of some galaxies. These
    black holes feed on large volumes of cosmic dust and gas. Before it is
    eaten up, this material spirals towards the black hole and huge amounts
    of energy are released in the process, often outshining all the stars
    in the galaxy.

    Astronomers have been curious about AGNs ever since they first spotted
    these bright objects in the 1950s. Now, thanks to ESO's VLTI, a team of researchers, led by Violeta Ga'mez Rosas from Leiden University in the Netherlands, have taken a key step towards understanding how they work and
    what they look like up close. The results are published today in Nature.

    By making extraordinarily detailed observations of the centre of the
    galaxy Messier 77, also known as NGC 1068, Ga'mez Rosas and her team
    detected a thick ring of cosmic dust and gas hiding a supermassive black
    hole. This discovery provides vital evidence to support a 30-year-old
    theory known as the Unified Model of AGNs.

    Astronomers know there are different types of AGN. For example, some
    release bursts of radio waves while others don't; certain AGNs shine
    brightly in visible light, while others, like Messier 77, are more
    subdued. The Unified Model states that despite their differences, all
    AGNs have the same basic structure: a supermassive black hole surrounded
    by a thick ring of dust.

    According to this model, any difference in appearance between AGNs results
    from the orientation at which we view the black hole and its thick ring
    from Earth.

    The type of AGN we see depends on how much the ring obscures the black
    hole from our view point, completely hiding it in some cases.



    ========================================================================== Astronomers had found some evidence to support the Unified Model before, including spotting warm dust at the centre of Messier 77. However,
    doubts remained about whether this dust could completely hide a black
    hole and hence explain why this AGN shines less brightly in visible
    light than others.

    "The real nature of the dust clouds and their role in both feeding the
    black hole and determining how it looks when viewed from Earth have
    been central questions in AGN studies over the last three decades,"
    explains Ga'mez Rosas.

    "Whilst no single result will settle all the questions we have, we have
    taken a major step in understanding how AGNs work." The observations were
    made possible thanks to the Multi AperTure mid-Infrared SpectroScopic Experiment (MATISSE) mounted on ESO's VLTI, located in Chile's Atacama
    Desert. MATISSE combined infrared light collected by all four 8.2-metre telescopes of ESO's Very Large Telescope (VLT) using a technique called interferometry. The team used MATISSE to scan the centre of Messier 77,
    located 47 million light-years away in the constellation Cetus.

    "MATISSE can see a broad range of infrared wavelengths, which lets us
    see through the dust and accurately measure temperatures. Because the
    VLTI is in fact a very large interferometer, we have the resolution
    to see what's going on even in galaxies as far away as Messier 77. The
    images we obtained detail the changes in temperature and absorption of
    the dust clouds around the black hole," says co-author Walter Jaffe,
    a professor at Leiden University.

    Combining the changes in dust temperature (from around room temperature
    to about 1200 DEGC) caused by the intense radiation from the black
    hole with the absorption maps, the team built up a detailed picture
    of the dust and pinpointed where the black hole must lie. The dust --
    in a thick inner ring and a more extended disc -- with the black hole positioned at its centre supports the Unified Model. The team also used
    data from the Atacama Large Millimeter/ submillimeter Array, co-owned by
    ESO, and the National Radio Astronomy Observatory's Very Long Baseline
    Array to construct their picture.

    "Our results should lead to a better understanding of the inner
    workings of AGNs," concludes Ga'mez Rosas. "They could also help
    us better understand the history of the Milky Way, which harbours a supermassive black hole at its centre that may have been active in
    the past." The researchers are now looking to use ESO's VLTI to find
    more supporting evidence of the Unified Model of AGNs by considering a
    larger sample of galaxies.

    Team member Bruno Lopez, the MATISSE Principal Investigator at the
    Observatoire de la Co^te d'Azur in Nice, France, says: "Messier 77 is an important prototype AGN and a wonderful motivation to expand our observing programme and to optimise MATISSE to tackle a wider sample of AGNs." ========================================================================== Story Source: Materials provided by ESO. Note: Content may be edited
    for style and length.


    ========================================================================== Related Multimedia:
    * Dazzling_galaxy_Messier_77 ========================================================================== Journal Reference:
    1. Ga'mez Rosas, V., Isbell, J.W., Jaffe, W. et al. Thermal imaging
    of dust
    hiding the black hole in the Active Galaxy NGC 1068. Nature,
    2022 DOI: 10.1038/s41586-021-04311-7 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/02/220216112207.htm

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