Loading ...
Sorry, an error occurred while loading the content.
 

New Panorama Reveals More Than A Thousand Black Holes

Expand Messages
  • derhexer@aol.com
    URL to an article from ScienceDaily News _http://www.sciencedaily.com/releases/2007/03/070312111251.htm_
    Message 1 of 2 , Mar 16, 2007
      URL to an article from ScienceDaily News
      _http://www.sciencedaily.com/releases/2007/03/070312111251.htm_
      (http://www.sciencedaily.com/releases/2007/03/070312111251.htm)

      It is sometimes boggling that we can get this sort of information up to a
      range of 11 billion Ely

      First few paragraphs
      "
      New Panorama Reveals More Than A Thousand Black Holes
      _Science Daily_ (http://www.sciencedaily.com/) — By casting a wide net,
      astronomers have captured an image of more than a thousand supermassive black
      holes. These results give astronomers a snapshot of a crucial period when these
      monster black holes are growing, and provide insight into the environments
      in which they occur.

      Bootes Field: New Panorama Reveals More Than a Thousand Black Holes. A new
      wide-field panorama reveals more than a thousand supermassive black holes in
      the centers of galaxies, some up to several billion times more massive than
      the sun. This survey, taken in a region of the Bootes constellation, involved
      126 separate Chandra exposures of 5,000-seconds each, making it the largest
      contiguous field ever obtained by the observatory. At 9.3 square degrees, it is
      over 40 times larger than the full moon seen on the night sky, which is also
      shown in this graphic for scale. In this image, the red represents
      low-energy X-rays, green shows the medium range, and blue the higher energy X-rays.
      (Credit: X-ray: NASA/CXC/CfA/R.Hickox et al.; Moon: NASA/JPL)
      The new black hole panorama was made with data from NASA's Chandra X-ray
      Observatory, the Spitzer Space Telescope and ground-based optical telescopes.
      The black holes in the image are hundreds of millions to several billion times
      more massive than the sun and lie in the centers of galaxies.
      Material falling into these black holes at high rates generates huge amounts
      of light that can be detected in different wavelengths. These systems are
      known as active galactic nuclei, or AGN.
      "We're trying to get a complete census across the universe of black holes and
      their habits," said Ryan Hickox of the Harvard-Smithsonian Center for
      Astrophysics (CfA) in Cambridge, Mass. "We used special tactics to hunt down the
      very biggest black holes."
      Instead of staring at one relatively small part of the sky for a long time,
      as with the Chandra Deep Fields -- two of the longest exposures obtained with
      the observatory -- and other concentrated surveys, this team scanned a much
      bigger portion with shorter exposures. Since the biggest black holes power the
      brightest AGN, they can be spotted at vast distances, even with short
      exposures.
      "With this approach, we found well over a thousand of these monsters, and
      have started using them to test our understanding of these powerful objects,"
      said co-investigator Christine Jones, also of the CfA.
      The new survey raises doubts about a popular current model in which a
      supermassive black hole is surrounded by a doughnut-shaped region, or torus, of
      gas. An observer from Earth would have their view blocked by this torus by
      different amounts, depending on the orientation of the torus.
      According to this model, astronomers would expect a large sample of black
      holes to show a range of absorption of the radiation from the nuclei. This
      absorption should range from completely exposed to completely obscured, with most
      in-between. Nuclei that are completely obscured are not detectable, but
      heavily obscured ones are.
      "Instead of finding a whole range, we found nearly all of the black holes are
      either naked or covered by a dense veil of gas," said Hickox. "Very few are
      in between, which makes us question how well we know the environment around
      these black holes."



      ************************************** AOL now offers free email to everyone.
      Find out more about what's free from AOL at http://www.aol.com


      [Non-text portions of this message have been removed]
    • Aleus Mundi
      Is it part of the missing mass? ... -- The Transmundial rules all [Non-text portions of this message have been removed]
      Message 2 of 2 , Mar 18, 2007
        Is it part of the missing mass?

        On 3/16/07, derhexer@... <derhexer@...> wrote:
        >
        > URL to an article from ScienceDaily News
        > _http://www.sciencedaily.com/releases/2007/03/070312111251.htm_
        > (http://www.sciencedaily.com/releases/2007/03/070312111251.htm)
        >
        > It is sometimes boggling that we can get this sort of information up to a
        > range of 11 billion Ely
        >
        > First few paragraphs
        > "
        > New Panorama Reveals More Than A Thousand Black Holes
        > _Science Daily_ (http://www.sciencedaily.com/) � By casting a wide net,
        > astronomers have captured an image of more than a thousand supermassive
        > black
        > holes. These results give astronomers a snapshot of a crucial period when
        > these
        > monster black holes are growing, and provide insight into the environments
        >
        > in which they occur.
        >
        > Bootes Field: New Panorama Reveals More Than a Thousand Black Holes. A new
        >
        > wide-field panorama reveals more than a thousand supermassive black holes
        > in
        > the centers of galaxies, some up to several billion times more massive
        > than
        > the sun. This survey, taken in a region of the Bootes constellation,
        > involved
        > 126 separate Chandra exposures of 5,000-seconds each, making it the
        > largest
        > contiguous field ever obtained by the observatory. At 9.3 square degrees,
        > it is
        > over 40 times larger than the full moon seen on the night sky, which is
        > also
        > shown in this graphic for scale. In this image, the red represents
        > low-energy X-rays, green shows the medium range, and blue the higher
        > energy X-rays.
        > (Credit: X-ray: NASA/CXC/CfA/R.Hickox et al.; Moon: NASA/JPL)
        > The new black hole panorama was made with data from NASA's Chandra X-ray
        > Observatory, the Spitzer Space Telescope and ground-based optical
        > telescopes.
        > The black holes in the image are hundreds of millions to several billion
        > times
        > more massive than the sun and lie in the centers of galaxies.
        > Material falling into these black holes at high rates generates huge
        > amounts
        > of light that can be detected in different wavelengths. These systems are
        > known as active galactic nuclei, or AGN.
        > "We're trying to get a complete census across the universe of black holes
        > and
        > their habits," said Ryan Hickox of the Harvard-Smithsonian Center for
        > Astrophysics (CfA) in Cambridge, Mass. "We used special tactics to hunt
        > down the
        > very biggest black holes."
        > Instead of staring at one relatively small part of the sky for a long
        > time,
        > as with the Chandra Deep Fields -- two of the longest exposures obtained
        > with
        > the observatory -- and other concentrated surveys, this team scanned a
        > much
        > bigger portion with shorter exposures. Since the biggest black holes power
        > the
        > brightest AGN, they can be spotted at vast distances, even with short
        > exposures.
        > "With this approach, we found well over a thousand of these monsters, and
        > have started using them to test our understanding of these powerful
        > objects,"
        > said co-investigator Christine Jones, also of the CfA.
        > The new survey raises doubts about a popular current model in which a
        > supermassive black hole is surrounded by a doughnut-shaped region, or
        > torus, of
        > gas. An observer from Earth would have their view blocked by this torus by
        >
        > different amounts, depending on the orientation of the torus.
        > According to this model, astronomers would expect a large sample of black
        > holes to show a range of absorption of the radiation from the nuclei. This
        >
        > absorption should range from completely exposed to completely obscured,
        > with most
        > in-between. Nuclei that are completely obscured are not detectable, but
        > heavily obscured ones are.
        > "Instead of finding a whole range, we found nearly all of the black holes
        > are
        > either naked or covered by a dense veil of gas," said Hickox. "Very few
        > are
        > in between, which makes us question how well we know the environment
        > around
        > these black holes."
        >
        > ************************************** AOL now offers free email to
        > everyone.
        > Find out more about what's free from AOL at http://www.aol.com
        >
        > [Non-text portions of this message have been removed]
        >
        >
        >



        --
        The Transmundial rules all


        [Non-text portions of this message have been removed]
      Your message has been successfully submitted and would be delivered to recipients shortly.