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Thread: Older Papers

  1. #1
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    Older Papers

    Galactic Rotation Described with Bulge+Disk Gravitational Models
    C. F. Gallo, James Q. Feng
    (Submitted on 20 Apr 2008)
    http://search.arxiv.org:8081/details...df/0804.3203v1
    (1) Balancing Newtonian gravitational and centrifugal forces at every point within the disk yields computed radial mass distributions that describe the measured rotation velocity profiles of mature spiral galaxies successfully. (2) There is no need for gravity deviations or ``massive peripheral spherical halos of mysterious Dark Matter''.
    GBT Multiwavelength Survey of the Galactic Center Region
    (Submitted on 28 Jan 2008)
    http://search.arxiv.org:8081/paper.j...the+GBT+survey
    We describe the results of a radio continuum survey of the central 4x1deg with the 100 m Green Bank Telescope (GBT) at wavelengths of 3.5, 6, 20, and 90 cm. The 3.5 and 6 cm surveys are the most sensitive and highest resolution single dish surveys made of the central degrees of our Galaxy. We present catalogs of compact and extended sources in the central four degrees of our Galaxy, including detailed spectral index studies of all sources. The analysis covers star-forming regions such as Sgr B and Sgr C where we find evidence of a mixture of thermal and nonthermal emission

  2. #2
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    So?

    What is your point?
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  3. #3
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    The first paper is basically just a cold, baryonic dark matter model. They assume that star density is not as well correlated with overall mass distribution as current models, work back to a mass distribution that does fit observed rotational curves and say "if our assumptions are true then this must be the mass distribution of the galaxy". They then assign this extra mass to clouds of molecular hydrogen, assume that current estimates of its density are way too low and voila - a solution. So they replace DM (because it has such odd properties - it is invisible, we are not sure what it is, we only know it is there by its gravity) with molecular hydrogen (which has the preferable properties that it is invisible, we do not know how it behaves in their models as it doesn't quite seem to behave like we'd expect and we only know it is there by its gravity)... Umm...

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    Don J we don't get what point you are making with the second paper. Are you saying they have detected a lot of hitherto undetected gas ?

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    Quote Originally Posted by Shaula View Post
    The first paper is basically just a cold, baryonic dark matter model. They assume that star density is not as well correlated with overall mass distribution as current models, work back to a mass distribution that does fit observed rotational curves and say "if our assumptions are true then this must be the mass distribution of the galaxy". They then assign this extra mass to clouds of molecular hydrogen, assume that current estimates of its density are way too low and voila - a solution. So they replace DM (because it has such odd properties - it is invisible, we are not sure what it is, we only know it is there by its gravity) with molecular hydrogen (which has the preferable properties that it is invisible, we do not know how it behaves in their models as it doesn't quite seem to behave like we'd expect and we only know it is there by its gravity)... Umm...
    Based on what is described in 1.2 i was thinking that it was the the orbital velocity law applied to rotating galactic disk they were challenging for the reason they are giving .So it seem that they are doing more than just replacing dark matter molecular hydrogen.

    http://search.arxiv.org:8081/details...df/0804.3203v1

    1.2 Thin-Disk Gravitational Models with Bulge Added

    For a thin rotating galactic disk, we impose a balance between the Newtonian gravitational forces and centrifugal forces at each and every point. Because the gravitational field of a thin disk is not spherically symmetric, the orbital velocity law is not applicable. As illustrated by Feng & Gallo [8] [9], an axisymmetric thin disk gravitational model successfully describes the basic rotational dynamics of mature spiral galaxies with a mass density decreasing from the center to periphery. And the calculated total galactic masses are in good agreement with star count data.
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    Galactic Rotation Described with Bulge+Disk Gravitational Models

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    Galactic Rotation... no need for dark matter.
    http://www.bautforum.com/showthread....07#post2011607
    Last edited by Don J; 2012-Apr-26 at 05:08 AM.

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    Quote Originally Posted by kzb View Post
    Don J we don't get what point you are making with the second paper. Are you saying they have detected a lot of hitherto undetected gas ?
    The second paper was included here because it is an old paper and not because it relate with the first paper.But it is cool notheless.

    Originally posted by mistake in Fun Papers In Arxiv thread.

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    Galactic Rotation Described with Bulge+Disk Gravitational Models

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    Galactic Rotation... no need for dark matter.
    http://www.bautforum.com/showthread....07#post2011607

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    Moderators

    It may be preferable to close this thread to avoid any confusion.

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    Quote Originally Posted by Don J View Post
    Moderators

    It may be preferable to close this thread to avoid any confusion.
    Done
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    Good idea, closed
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