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Nice picture of quasar accretion disk-pat on back for standard cosmology in Nature

  1. Jul 26, 2008 #1

    marcus

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    Nice picture of quasar accretion disk---pat on back for standard cosmology in Nature

    The 24 July issue of Nature reports some beautiful observational work, using a polarized light filter.
    Actually able to SEE the hot blue accretion disk whirling around a supermassive black hole at the center of a quasar galaxy
    In case anybody still had doubts about what quasars are, this should help remedy them.

    I don't think the standard cosmology picture is seriously controversial at this point, given the immense amount of consistently supportive data. So maybe confirmation like these quasar observations is superfluous. But that's my perspective----other people may welcome this as additional confirmation, a pat on the back.

    http://arxiv.org/abs/0807.3703
    The characteristic blue spectra of accretion disks in quasars as uncovered in the infrared
    Makoto Kishimoto (1,2), Robert Antonucci (3), Omer Blaes (3), Andy Lawrence (2), Catherine Boisson (4), Marcus Albrecht (5), Christian Leipski (3) ((1)MPIfR, (2)Edinburgh, (3)UCSB, (4)Paris Obs, (5)UCN)
    (Submitted on 23 Jul 2008)

    "Quasars are thought to be powered by supermassive black holes accreting surrounding gas. Central to this picture is a putative accretion disk which is believed to be the source of the majority of the radiative output. It is well known, however, that the most extensively studied disk model -- an optically thick disk which is heated locally by the dissipation of gravitational binding energy -- is apparently contradicted by observations in a few major respects. In particular, the model predicts a specific blue spectral shape asymptotically from the visible to the near-infrared, but this is not generally seen in the visible wavelength region where the disk spectrum is observable. A crucial difficulty was that, toward the infrared, the disk spectrum starts to be hidden under strong hot dust emission from much larger but hitherto unresolved scales, and thus has essentially been impossible to observe. Here we report observations of polarized light interior to the dust-emiting region that enable us to uncover this near-infrared disk spectrum in several quasars. The revealed spectra show that the near-infrared disk spectrum is indeed as blue as predicted. This indicates that, at least for the outer near-infrared-emitting radii, the standard picture of the locally heated disk is approximately correct. The model problems at shorter wavelengths should then be directed toward a better understanding of the inner parts of the revealed disk. The newly uncovered disk emission at large radii, with more future measurements, will also shed totally new light on the unanswered critical question of how and where the disk ends."

    Comments: published in Nature, 24 July 2008 issue. Supplementary Information can be found at http://www.mpifr-bonn.mpg.de/div/ir-interferometry/suppl_info.pdf
    Published version can be accessed from http://www.nature.com/nature/journal/v454/n7203/pdf/nature07114.pdf

    ===============================

    Science Daily 24 July has a story on it, with a photograph of the accretion disk:
    http://www.sciencedaily.com/releases/2008/07/080723142119.htm
     
    Last edited: Jul 26, 2008
  2. jcsd
  3. Jul 26, 2008 #2
    Re: Nice picture of quasar accretion disk---pat on back for standard cosmology in Nat

    Icing on the cake! But definitely appreciated I'm sure. Observational techniques are so fascinating. Almost as impressive as what they are used to revel.
     
  4. Jul 27, 2008 #3

    wolram

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    Re: Nice picture of quasar accretion disk---pat on back for standard cosmology in Nat

    They exist but some of there masses seem extreme compared to the age of the U.
     
  5. Jul 27, 2008 #4

    Chronos

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    Re: Nice picture of quasar accretion disk---pat on back for standard cosmology in Nat

    Perhaps such masses are not as well established as the age of the universe.
     
  6. Jul 27, 2008 #5

    wolram

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    Re: Nice picture of quasar accretion disk---pat on back for standard cosmology in Nat

    Chronos, do you think the 1% more or less mass attributed to BHs may be over estimated, this mass may not be significant but interesting.
     
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