What color is the dark matter

Discussion in 'Astronomy, Exobiology, & Cosmology' started by timojin, Oct 17, 2016.

  1. The God Valued Senior Member

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    3,546
    You know I am never wrong.
    And what difficulty you are talking about? Rpenner? He is a nice bloke with good command over typing formulas. He feels that people do not know that density is m/V, although true in your case, but for every small small issues he showcases his latex expertise. He has to learn to express himself in less maths language.
     
    Last edited: Oct 23, 2016
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  3. paddoboy Valued Senior Member

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    Again, my friend, your obfuscation and nit picking is fooling no one.
    We are mainly speaking of DM, which you foolishly asociate with colour and which you foolishly totally deny anyway.
    My comprehension, despite your usual unsupported claims is quite adequate.
    And unlike you, I do not need to nit pick, obfuscate and insult, as you are doing, just to make some frivilous, unrelated point...whatever that is.
     
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  5. paddoboy Valued Senior Member

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    No not wrong, and yes I remember vividly. In fact at least two Professors from memory, invalidated your claims....and agreed with mine, as simplistic as it was.
     
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  7. The God Valued Senior Member

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    Pl cite where I associated DM with color. You only were mistakenly posting about absence of color. I was just bringing you to track.
     
  8. The God Valued Senior Member

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    3,546

    Professors agreed with yours???

    Quite ludicrous claim!!
     
  9. paddoboy Valued Senior Member

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    27,543
    Absence of colour with regard to DM, yep, certainly. And contrary to your claim about bringing back on track, obviously you were doing what you are renowned for: covering your own previous misgivings, mistakes and errors.

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  10. Q-reeus Banned Valued Senior Member

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    4,695
    While others agreed with mine and ipso facto 'invalidated your position'. Which is a silly way to settle things. Fact is gravity is not a source term in EFE's. In some other theories of gravity it really is true that 'gravity gravitates' - and one has there no need of quaint 'fossil fields' concept.
     
  11. The God Valued Senior Member

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    3,546
    Stupid post to mislead and evade... I have no previous misgivings, mistakes and errors.
     
  12. paddoboy Valued Senior Member

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    Check out the fringes, red pennings, and warnings.

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  13. The God Valued Senior Member

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    Last time I checked, cesspool contains more thread with your name than....
     
  14. paddoboy Valued Senior Member

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    27,543
    No not really. Many in alternatives, speudo and cesspool:
    Threads of mine that are there in one from memory due to content in OP and it was not on cosmology, and was supported by a arxiv paper also.
    I'm afraid my friend, this is one time you certainly come out on top!

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    congrats!!!
     
  15. The God Valued Senior Member

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    3,546
    I am always on top!! Wherever I am.
     
  16. paddoboy Valued Senior Member

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    Ignoring the nonsense.

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    As we have concluded DM of the exotic/WIMP kind has no colour, because it neither absorbs and/or reflects EMR, the most recognised evidence for DM is the "Bullet Cluster" observation.....
    http://chandra.harvard.edu/press/06_releases/press_082106.html
    NASA Finds Direct Proof of Dark Matter

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    X-ray/Optical Composite of 1E 0657-56

    Dark matter and normal matter have been wrenched apart by the tremendous collision of two large clusters of galaxies. The discovery, using NASA's Chandra X-ray Observatory and other telescopes, gives direct evidence for the existence of dark matter.

    "This is the most energetic cosmic event, besides the Big Bang, which we know about," said team member Maxim Markevitch of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.
    Please note: The blue/red colours for illustrative purposes only.

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    Other similar collisions since have also seen similar.
     
  17. The God Valued Senior Member

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    3,546
    I think most here know this. What value you are adding with this copy paste? Is the DM only explanation for this observation?
     
  18. paddoboy Valued Senior Member

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    I'm offering information, based on data from observation, to counter your nonsensical games and obfuscation.

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  19. LaurieAG Registered Senior Member

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  20. The God Valued Senior Member

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    3,546

    What is the significance of

    Md + Mo = 2 * pi * Mo ?
     
  21. Boris2 Valued Senior Member

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    1,106
    Argument from Personal Incredulity: Asserting that opponent’s argument must be false because you personally don’t understand it or can’t follow its technicalities. For instance, one person might assert, “I don’t understand that engineer’s argument about how airplanes can fly. Therefore, I cannot believe that airplanes are able to fly.” Au contraire, that speaker’s own mental limitations do not limit the physical world—so airplanes may very well be able to fly in spite of a person's inability to understand how they work. One person’s comprehension is not relevant to the truth of a matter.
     
  22. paddoboy Valued Senior Member

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    When posters claim they are never wrong, the word "buffoonery" straight away comes to mind. So we'll ignore such buffoonery and present a couple of papers from data from the Planck probe and a continuation of Laurie's post at 56.

    https://arxiv.org/pdf/1502.01589v3.pdf

    Abstract:

    This paper presents cosmological results based on full-mission Planck observations of temperature and polarization anisotropies of the cosmic microwave background (CMB) radiation. Our results are in very good agreement with the 2013 analysis of the Planck nominal-mission temperature data, but with increased precision. The temperature and polarization power spectra are consistent with the standard spatially-flat 6-parameter ΛCDM cosmology with a power-law spectrum of adiabatic scalar perturbations (denoted “base ΛCDM” in this paper). From the Planck temperature data combined with Planck lensing, for this cosmology we find a Hubble constant, H0 = (67.8±0.9) km s−1Mpc−1 , a matter density parameter Ωm = 0.308±0.012, and a tilted scalar spectral index with ns = 0.968±0.006, consistent with the 2013 analysis. Note that in this abstract we quote 68 % confidence limits on measured parameters and 95 % upper limits on other parameters. We present the first results of polarization measurements with the Low Frequency Instrument at large angular scales. Combined with the Planck temperature and lensing data, these measurements give a reionization optical depth of τ = 0.066 ± 0.016, corresponding to a reionization redshift of zre = 8.8 +1.7 −1.4 . These results are consistent with those from WMAP polarization measurements cleaned for dust emission using 353-GHz polarization maps from the High Frequency Instrument. We find no evidence for any departure from base ΛCDM in the neutrino sector of the theory; for example, combining Planck observations with other astrophysical data we find Neff = 3.15±0.23 for the effective number of relativistic degrees of freedom, consistent with the value Neff = 3.046 of the Standard Model of particle physics. The sum of neutrino masses is constrained to P mν < 0.23 eV. The spatial curvature of our Universe is found to be very close to zero, with |ΩK| < 0.005. Adding a tensor component as a single-parameter extension to base ΛCDM we find an upper limit on the tensor-to-scalar ratio of r0.002 < 0.11, consistent with the Planck 2013 results and consistent with the B-mode polarization constraints from a joint analysis of BICEP2, Keck Array, and Planck (BKP) data. Adding the BKP B-mode data to our analysis leads to a tighter constraint of r0.002 < 0.09 and disfavours inflationary models with a V(φ) ∝ φ 2 potential. The addition of Planck polarization data leads to strong constraints on deviations from a purely adiabatic spectrum of fluctuations. We find no evidence for any contribution from isocurvature perturbations or from cosmic defects. Combining Planck data with other astrophysical data, including Type Ia supernovae, the equation of state of dark energy is constrained to w = −1.006 ± 0.045, consistent with the expected value for a cosmological constant. The standard big bang nucleosynthesis predictions for the helium and deuterium abundances for the best-fit Planck base ΛCDM cosmology are in excellent agreement with observations. We also analyse constraints on annihilating dark matter and on possible deviations from the standard recombination history. In neither case do we find no evidence for new physics. The Planck results for base ΛCDM are in good agreement with baryon acoustic oscillation data and with the JLA sample of Type Ia supernovae. However, as in the 2013 analysis, the amplitude of the fluctuation spectrum is found to be higher than inferred from some analyses of rich cluster counts and weak gravitational lensing. We show that these tensions cannot easily be resolved with simple modifications of the base ΛCDM cosmology. Apart from these tensions, the base ΛCDM cosmology provides an excellent description of the Planck CMB observations and many other astrophysical data sets.


    In summary,
    the Planck temperature and polarization spectra presented in Figs. 1 and 3 are more precise (and accurate) than those from any previous CMB experiment, and improve on the 2013 spectra presented in PCP13. Yet we find no signs for any significant deviation from the base ΛCDM cosmology. Similarly, the analysis of 2015 Planck data reported in Planck Collaboration XVII (2016) sets unprecedentedly tight limits on primordial non-Gaussianity. The Planck results offer powerful evidence in favour of simple inflationary models, which provide an attractive mechanism for generating the slightly tilted spectrum of (nearly) Gaussian adiabatic perturbations that match our data to such high precision. In addition, the Planck data show that the neutrino sector of the theory is consistent with the assumptions of the base ΛCDM model and that the dark energy is compatible with a cosmological constant. If there is new physics beyond base ΛCDM, then the corresponding observational signatures in the CMB are weak and difficult to detect. This is the legacy of the Planck mission for cosmology.
     
    Last edited: Oct 24, 2016
  23. paddoboy Valued Senior Member

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    27,543
    https://arxiv.org/pdf/1504.01195v1.pdf

    Constraints on the basic parameters of dark matter using the Planck data:

    Dark Matter annihilation or decay can affect the anisotropy of the cosmic microwave background (CMB). Therefore, the CMB data can be used to constrain the properties of a dark matter particle. In this work, we use the new CMB data obtained by the Planck satellite to investigate the limits on the basic parameters of a dark matter particle. The parameters are the dark matter mass (mχ) and the thermally averaged cross section (hσvi) for dark matter annihilation and the decay rate (Γ) (or lifetime τ = 1/Γ) for dark matter decay. For dark matter annihilation we also consider the impact of the structure formation process which is neglected by the recent work. We find that for DM annihilation, the constraints on the parameters are fann = hσvi/mχ < 0.16×10−26cm3 s −1GeV−1 (or fann < 0.89 × 10−6m 3 s −1 kg−1 , 95% C.L.). For DM decay, the constraints on the decay rate are Γ < 0.28 × 10−25s −1 (95% C.L.).

    SUMMARY AND DISCUSSION

    In this work, we used the new data from the Planck satellite to investigate the limits on the DM basic parameters for the annihilation and decay. By considering the structure formation effect for the DM annihilation case, we found that the constraints on the fann parameter are fann < 0.16(0.24) × 10−26cm3 s −1GeV−1 or fann < 0.89(1.34) × 10−6m3 s −1kg−1 (95% C.L.). For the DM decay, the constraints on the decay rate are Γ < 0.28 × 10−25s −1 (95% C.L.). As mentioned in the Sec.II, for the clumpy DM distribution, the smallest mass of DM halo is set as ∼ 10−6M⊙, which is different for different DM models. In theory for WIMPs DM, this value ranges from 10−12M⊙ to 10−4M⊙ for typical kinetic decoupling temperatures. From the results of current numerical simulations, the typical smallest mass of DM halos is ∼ 106M⊙. In Ref. [15], the authors discussed the effects on the ’boost factor’ for the different values of the smallest DM halos. They found that there are differences of ∼ 2 orders of magnitude of the ’boost factor’ for DM halo mass 10−12M⊙ and 10−4M⊙ at z ∼ 50 (upper panel of Fig. 1 in Ref. [15]). For DM halo mass 106M⊙, the differences of ∼ 5 orders of magnitude differences are present at z ∼ 20 compared with the DM smooth distribution. Therefore, the largest differences usually appear in nearby universe, and it is believed that the changes of limits on the DM parameters are slight if one change the values of the smallest mass of DM halos. Another factor which can affect the limits on the DM is the density profile of DM halos. In this work, we have used the NFW profile, which is well in fitting many observations data. In addition there are still many other observations or N-body simulations which are favored by the other profiles, such as Einasto profile [21–24], which are slightly different from that of NFW profile for the final constrains. One point in this work that should be noticed is that we have set f(z) as a free parameter, and for the final constraints we have set f(z) = 1, which means that all the energy produced by the DM annihilation or decay has deposited into the medium of the Universe. In Ref. [11], the dependence of f(z) on the redshift and different annihilation channels were discussed by the authors. It can be seen that the final constraints are slightly different (Table II of Ref. [11]. NOTE: the latest constraints on the DM parameters for annihilation can be found in the paper of Planck Collaboration (arXiv:1502.01589).
     

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