Galactic halo

The principle of nuclear democracy is invoked to prove the formation of stable quantized gravitational bound states of primordial black holes called Holeums. The latter come in four varieties: ordinary Holeums H, Black Holeums BH, Hyper Holeums HH and the massless Lux Holeums LH.These Holeums are invisible because the gravitational radiation emitted by their quantum transitions is undetectable now. The

This paper is nothing short of a positive and complete verification of the unification of current physics paradigms of single field theory (SOFT) in light of recently published observational data in astronomy. An article by Sabine Hossenfelder and Stacey S. McGaugh, titled " Is Dark Matter Real?', has just appeared in the August 2018 issue of Scientific American. Every physicist, astronomer, astrophysicist and cosmologist as well as everyone interested in science needs to read this article because it portends one of the greatest scientific advances in several hundred years, the complete unification of physics and science in general. Due to new observational evidence in astronomy, they have concluded that " Astrophysicists have piled up observations that are difficult to explain with Dark Matter. It is time to consider that there may be more to gravity than Einstein taught us. " But they have understated the case. In effect, the new observational data found by McGaugh and an international group of astronomers clearly shows that specifically designated dark matter particles do not exist, so the supposed Dark Matter halos around spiral galaxies do not exist and the rotational speed discrepancies in galaxy orbiting stars and star systems that go unaccounted for by normal gravity are, in fact, due to a secondary effect of normal matter within the galaxy. This finding not only challenges the present theories of gravity (Newtonian and Einsteinian), which it demonstrates are incomplete, it also blows some big logical holes in the fundamentality of the quantum theory, the Standard Model of point-particles and quantum field theories in general that seem to rule the world of modern theoretical physics. Given other recent confirmations of Einstein's general relativity, found mostly in the detection of gravitational waves that Einstein predicted a century ago, relativity theory seems on the ascendancy and quantum theory is falling behind. The time for a unified field theory that combines the best of both paradigms is at hand.

There is compelling observational evidence for the existence of dark matter. Although knowledge of its underlying nature remains elusive, a variety of theories provide candidate particles [1]. Among those are supersymmetry [2] and universal extra dimensions [3], both of which predict new physics at the electro-weak scale and, in most scenarios, introduce a light, and stable (or long lived) particle that exhibits the properties of a weakly interacting massive particle (WIMP)[4]. WIMPs are an ideal dark matter candidate, predicted to have ...

We reanalyze the kinematics and dynamics of the system of blue horizontal-branch field (BHBF) stars in the Galactic halo (in particular the outer halo), fitting the kinematics with the model of radial and tangential velocity dispersions in the halo as a function of Galactocentric distance r proposed by Sommer-Larsen, Flynn, & Christensen but making use of a much larger sample of BHBF stars than was previously available. The present sample consists of nearly 700 Galactic halo BHBF stars. A very good fit to the observations is obtained. The basic result is that the radial component, sigma r, of the stellar halo's velocity ellipsoid decreases fairly rapidly beyond the solar circle. The observed decrease is from sigma r ~= 140 +/- 10 km s-1 at the Sun to an asymptotic value of sigma r = 89 +/- 19 km s-1 at large r. The rapid decrease in sigma r is matched by an increase in the tangential velocity dispersion, sigma t, with increasing r. Thus, the character of the stellar halo veloci...

SBS 1150+599A is a blue stellar object at high galactic latitude discovered in the Second Byurakan Survey. New high-resolution images of SBS 1150+599A are presented, demonstrating that it is very likely to be an old planetary nebula in the galactic halo, as suggested by Tovmassian et al (2001). An H-alpha image taken with the WIYN 3.5-m telescope and its "tip/tilt" module reveals the diameter of the nebula to be 9.2", comparable to that estimated from spectra by Tovmassian et al. Lower limits to the central star temperature were derived using the Zanstra hydrogen and helium methods to determine that the star's effective temperature must be > 68,000K and that the nebula is optically thin. New spectra from the MMT and FLWO telescopes are presented, revealing the presence of strong [Ne V] lambda 3425, indicating that the central star temperature must be > 100,000K. With the revised diameter, new central star temperature, and an improved central star luminosity, we can constrain photoionization models for the nebula significantly better than before. Because the emission-line data set is sparse, the models are still not conclusive. Nevertheless, we confirm that this nebula is an extremely metal-poor planetary nebula, having a value for O/H that is less than 1/100 solar, and possibly as low as 1/500 solar.

Abundance observations indicate the presence of rapid-neutron capture (i.e., r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the earliest generations of stars in the Galaxy -- the progenitors of the halo stars -- responsible for neutron-capture synthesis of the heavy elements. The large star-to-star scatter observed in the abundances of neutron-capture element/iron ratios at low metallicities -- which diminishes with increasing metallicity or [Fe/H] -- suggests the formation of these heavy elements (presumably from certain types of supernovae) was rare in the early Galaxy. The stellar abundances also indicate a change from the r-process to the slow neutron capture (i.e., s-) process at higher metallicities in the Galaxy and provide insight into Galactic chemical evolution. Finally, the detection of thorium and uranium in halo and globular cluster stars offers an independent age-dating technique that can put lower limits on the age of the Galaxy, and hence the Universe.

Observations on galactic scales seem to be in contradiction with recent high resolution N-body simulations. This so-called cold dark matter (CDM) crisis has been addressed in several ways, ranging from a change in fundamental physics by introducing self-interacting cold dark matter particles to a tuning of complex astrophysical processes such as global and/or local feedback. All these efforts attempt to soften density profiles and reduce the abundance of satellites in simulated galaxy halos. In this paper, we explore a somewhat different approach which consists of filtering the dark matter power spectrum on small scales, thereby altering the formation history of low mass objects. The physical motivation for damping these fluctuations lies in the possibility that the dark matter particles have a different nature i.e. are warm (WDM) rather than cold. We show that this leads to some interesting new results in terms of the merger history and large-scale distribution of low mass halos, as compared to the standard CDM scenario. However, WDM does not appear to be the ultimate solution, in the sense that it is not able to fully solve the CDM crisis, even though one of the main drawbacks, namely the abundance of satellites, can be remedied. Indeed, the cuspiness of the halo profiles still persists, at all redshifts, and for all halos and sub-halos that we investigated. Despite the persistence of the cuspiness problem of DM halos, WDM seems to be still worth taking seriously, as it alleviates the problems of overabundant sub-structures in galactic halos and possibly the lack of angular momentum of simulated disk galaxies. WDM also lessens the need to invoke strong feedback to solve these problems, and may provide a natural explanation of the clustering properties and ages of dwarfs.

We consider simple hydrodynamical models of galactic dark matter in which the galactic halo is a self-gravitating and sel-interacting gas that dominates the dynamics of the galaxy. Modeling this halo as a spherical symmetric and static perfect fluid satisfying the field equations of General Relativity, visible barionic matter can be treated as "test particles" in the geometry of this field. We show that the assumption of an empirical "universal rotation curve" that fits a wide variety of galaxies is compatible, under suitable approximations, with state variables characteristic of a non-relativistic Maxwell-Boltzmann gas that becomes an isothermal sphere in the Newtonian limit. Consistency criteria lead to a minimal bound for particle masses in the range 30 eV </= m </= 60 eV and to a constraint between the central temperature and the particles mass. The allowed mass range includes popular supersymmetric particle candidates, such as the neutralino, axino and...

uvby(-β) photometry has been obtained for an additional 411 very metal-poor stars selected from the HK survey, and used to derive basic parameters such as interstellar reddenings, metallicities, photometric classifications, distances, and relative ages. Interstellar reddenings adopted from the Schlegel et al. (\cite{schlegel}) maps agree well with those from the intrinsic-color calibration of Schuster & Nissen (\cite{schuster89}). [Fe/H] values are obtained from the CaII K line index of the HK survey combined with the uvby and UBV photometry. The c0,(b-y)0 diagram is seen to be very useful for classifying these very metal-poor field stars into categories similar to those derived from globular cluster color-magnitude diagrams; the HK survey has detected metal-poor candidates extending from the red-giant to the blue-horizontal branch, and from the horizontal branch to subluminous stars. Distances derived from UBV photometry agree reasonably well with those from uvby, considering the paucity of good calibrating stars and the extrapolations required for the most metal-poor stars. These very metal-poor stars are compared to M 92 in the c0,(b-y)0 diagram, and evidence is seen for field stars 1-3 Gyrs younger than this globular cluster; uncertainties in the [Fe/H] scale for M 92 would only tend to increase this age difference. Significant reddening uncertainties for M 92 are unlikely but might decrease this difference. The significance of these younger very metal-poor stars is discussed in the context of Galactic evolution, mentioning such possibilities as hierarchical star-formation/mass-infall of very metal-poor material and/or accretion events whereby this material has been acquired from other (dwarf) galaxies with different formation and chemical-enrichment histories. Based on observations collected at the H. L. Johnson 1.5 m telescope at the Observatorio Astronómico Nacional at San Pedro Mártir, Baja California, México, and at the Danish 1.5 m telescope, La Silla, Chile. Tables 1-9 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/422/527

In the indirect detection of dark matter through its annihilation products, the signals depend on the square of the dark matter density, making precise knowledge of the distribution of dark matter in the Universe critical for robust predictions. Many studies have focused on regions where the dark matter density is greatest, e.g., the Galactic Center, as well as on the cosmic signal arising from all halos in the Universe. We focus on the signal arising from the whole Milky Way halo; this is less sensitive to uncertainties in the dark matter distribution, and especially for flatter profiles, this halo signal is larger than the cosmic signal. We illustrate this by considering a dark matter model in which the principal annihilation products are neutrinos. Since neutrinos are the least detectable Standard Model particles, a limit on their flux conservatively bounds the dark matter total self-annihilation cross section from above. By using the Milky Way halo signal, we show that previous constraints using the cosmic signal can be improved on by 1-2 orders of magnitude; dedicated experimental analyses should be able to improve both by an additional 1-2 orders of magnitude.

We analyze the halo occupation distribution (HOD), the probability for a halo of mass M to host a number of subhalos N, and two-point correlation function of galaxy-size dark matter halos using high-resolution dissipationless simulations of the concordance flat LCDM model. The halo samples include both the host halos and the subhalos, distinct gravitationally-bound halos within the virialized regions of larger host systems. We find that the first moment of the HOD, <N>(M), has a complicated shape consisting of a step, a shoulder, and a power law high-mass tail. The HOD can be described by a Poisson statistics at high halo masses but becomes sub-Poisson for <N><4. We show that the HOD can be understood as a combination of the probability for a halo of mass M to host a central galaxy and the probability to host a given number Ns of satellite galaxies. The former can be approximated by a step-like function, while the latter can be well approximated by a Poisson distribution, fully specified by its first moment <Ns>(M). We find that <Ns>~M^b with b~1 for a wide range of number densities, redshifts, and different power spectrum normalizations. This formulation provides a simple but accurate model for the halo occupation distribution found in simulations. At z=0, the two-point correlation function (CF) of galactic halos can be well fit by a power law down to ~100/h kpc with an amplitude and slope similar to those of observed galaxies. At redshifts z>~1, we find significant departures from the power-law shape of the CF at small scales. If the deviations are as strong as indicated by our results, the assumption of the single power law often used in observational analyses of high-redshift clustering is likely to bias the estimates of the correlation length and slope of the correlation function.

From various cosmological, astrophysical and terrestrial requirements, we derive conservative upper bounds on the present-day fraction of the mass of the Galactic dark matter (DM) halo in charged massive particles (CHAMPs). If dark matter particles are neutral but decay lately into CHAMPs, the lack of detection of heavy hydrogen in sea water and the vertical pressure equilibrium in the Galactic disc turn out to put the most stringent bounds. Adopting very conservative assumptions about the recoiling velocity of CHAMPs in the decay and on the decay energy deposited in baryonic gas, we find that the lifetime for decaying neutral DM must be > (0.9-3.4)x 10^3 Gyr. Even assuming the gyroradii of CHAMPs in the Galactic magnetic field are too small for halo CHAMPs to reach Earth, the present-day fraction of the mass of the Galactic halo in CHAMPs should be < (0.4-1.4)x 10^{-2}. We show that redistributing the DM through the coupling between CHAMPs and the ubiquitous magnetic fields cannot be a solution to the cuspy halo problem in dwarf galaxies.

... (2.13) becomes wQE(W)= b 1v 2[exp(-bA2)-exp(-bx2)] b 3 (2.15 ... Also shown are two constant background rates: 0.5 counts/(kg keV day) (dotted) and 5 counts/(kg keV day) (dot-dash). 4 3 2 0 500 gm Si Diroc Neutrino E = 1.8 keV Threshold 0 5 10 mWIMP (GeV) I5 20 FIG. 15. ...