The conventional cold-particle interpretation of dark matter (known as 'cold dark matter', or CDM) still lacks laboratory support and struggles with the basic properties of common dwarf galaxies, which have surprisingly uniform central masses and shallow density profiles 1-5 . In contrast, galaxies predicted by CDM extend to much lower masses, with steeper, singular profiles 6-9 . This tension motivates cold, wavelike dark matter (ψDM) composed of a non-relativistic Bose-Einstein condensate, so the uncertainty principle counters gravity below a Jeans scale 10-12 . Here we achieve cosmological simulations of this quantum state at unprecedentedly high resolution capable of resolving dwarf galaxies, with only one free parameter, m B , the boson mass. We demonstrate the large-scale structure is indistinguishable from CDM, as desired, but di ers radically inside galaxies where quantum interference forms solitonic cores surrounded by extended haloes of fluctuating density granules. These results allow us to determine m B = (8.0 +1.8 −2.0 ) × 10 −23 eV using stellar phase-space distributions in dwarf spheroidal galaxies. Denser, more massive solitons are predicted for Milky Way sized galaxies, providing a substantial seed to help explain early spheroid formation. The onset of galaxy formation is substantially delayed relative to CDM, appearing at redshift z 13 in our simulations.Standard, thermally generated dark matter remains firmly undetected in laboratory searches for weakly interacting massive particles (WIMPs; ref. 13). Non-thermal bosonic fields, particularly scalar fields, provide another well-motivated class of dark matter, formed in a non-relativistic, low-momentum state as a cold Bose-Einstein condensate (BEC), and increasingly motivated by extensions of the Standard Model of particle physics and to the mechanism driving the universal expansion 14 . The field in this context can be described by a coherent wave function ψ with an interference pattern determining the distribution of dark matter, which we term ψDM. Axions are long-standing CDM candidates of this form, and higher-dimensional theories motivate an 'axiverse' , where a discrete mass spectrum of axion-like particles spans many decades, possibly affecting cosmic structure 15 .The distribution of ψDM mimics particle CDM on large scales 16,17 , and hence distinguishing between CDM and cold, wavelike ψDM is best made on small scales owing to the additional quantum stress [10][11][12]17 . Dwarf spheroidal (dSph) galaxies are the smallest and most common class of galaxy with internal motions dominated by dark matter. Their basic properties are very hard to explain with standard CDM, including the surprising uniformity of their central masses, M(<300 pc) 10 7 M , where M is the solar mass, and shallow density profiles 1-5 . In contrast, galaxies ) for the same cosmological parameters, with the high-k modes of the linear power spectrum intentionally suppressed in a way similar to the ψDM model to highlight the comparison of large-scale features. This compa...

We examine the nonlinear structure of gravitationally collapsed objects that form in our simulations of wavelike cold dark matter (ψDM), described by the Schrödinger-Poisson (SP) equation with a particle mass ∼ 10 −22 eV. A distinct gravitationally self-bound solitonic core is found at the center of every halo, with a profile quite different from cores modeled in the warm or self-interacting dark matter scenarios. Furthermore, we show that each solitonic core is surrounded by an extended halo composed of large fluctuating dark matter granules which modulate the halo density on a scale comparable to the diameter of the solitonic core. The scaling symmetry of the SP equation and the uncertainty principle tightly relate the core mass to the halo specific energy, which, in the context of cosmological structure formation, leads to a simple scaling between core mass (Mc) and haloh , where a is the cosmic scale factor. We verify this scaling relation by (i) examining the internal structure of a statistical sample of virialized halos that form in our 3D cosmological simulations, and by (ii) merging multiple solitons to create individual virialized objects. Sufficient simulation resolution is achieved by adaptive mesh refinement and graphic processing units acceleration. From this scaling relation, present dwarf satellite galaxies are predicted to have kpc sized cores and a minimum mass of ∼ 10 8 M⊙, capable of solving the small-scale controversies in the cold dark matter model. Moreover, galaxies of 2 × 10 12 M⊙ at z = 8 should have massive solitonic cores of ∼ 2 × 10 9 M⊙ within ∼ 60 pc. Such cores can provide a favorable local environment for funneling the gas that leads to the prompt formation of early stellar spheroids and quasars.PACS numbers: 03.75. Lm, 95.35.+d, 98.56.Wm, 98.62.Gq Accumulating evidences suggest that the Universe contains ∼ 26% dark matter [1] which interacts primarily through self-gravity. Dark matter comprising very light bosons with a mass m ψ ∼ 10 −22 eV has been recognized as a viable means of suppressing low mass galaxies and providing cored profiles in dark matter dominated galaxies [2,3]. Interestingly, this boson mass scale can naturally arise in a non-QCD axion model [4], lending support for the very light boson. The relative deficiency of the observed number of low-mass galaxies is a major problem for standard cold dark matter (CDM) [5][6][7], for which a steeply rising mass function is predicted [8]. Furthermore, the dwarf spheroidal galaxies [9-20] and low surface brightness galaxies [21,22] are generally inferred to have large flat cores of dark matter, at odds with the singular cores required by standard CDM [23,24]. Complicated baryonic physics such as supernova feedback is required to solve both issues in the CDM paradigm [25][26][27][28][29][30][31][32][33][34].Extremely light bosonic dark matter can be assumed to be non-thermally generated and described by a single coherent wave function [2,[35][36][37][38], which we term ψDM. Here solutions to both the missing-satellite and ...

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The newly established luminosity functions of high-z galaxies at 4 z 10 can provide a stringent check on dark matter models that aim to explain the core properties of dwarf galaxies. The cores of dwarf spheroidal galaxies are understood to be too large to be accounted for by free streaming of warm dark matter without overly suppressing the formation of such galaxies. Here we demonstrate with cosmological simulations that wave dark matter, ψDM, appropriate for light bosons such as axions, does not suffer this problem, given a boson mass of m ψ ≥ 1.2 × 10 −22 eV (2σ). In this case, the halo mass function is suppressed below ∼ 10 10 M at a level that is consistent with the high-z luminosity functions, while simultaneously generating the kpc-scale cores in dwarf galaxies arising from the solitonic ground state in ψDM. We demonstrate that the reionization history in this scenario is consistent with the Thomson optical depth recently reported by Planck, assuming a reasonable ionizing photon production rate. We predict that the luminosity function should turn over slowly around an intrinsic UV luminosity of M UV −16 at z 4. We also show that for galaxies magnified >10× in the Hubble Frontier Fields, ψDM predicts an order of magnitude fewer detections than cold dark matter at z 10 down to M UV ∼ −15, allowing us to distinguish between these very different interpretations for the observed coldness of dark matter.

A measurement of the cosmic ray positron fraction e+/(e++e−)e+/(e++e−) in the energy range of 1–30 GeV is presented. The measurement is based on data taken by the AMS-01 experiment during its 10 day Space Shuttle flight in June 1998. A proton background suppression on the order of 106 is reached by identifying converted bremsstrahlung photons emitted from positrons

We present nine color CCD intermediate-band spectrophotometry of a two square degree field centered on the old open cluster M67, from 3890$\rm \AA$ to nearly 1$\mu$. These observations are taken as a part of the BATC (Beijing-Arizona-Taipei-Connecticut) Color Survey of the Sky, for both scientific and calibration reasons. With these data we show that the BATC survey can reach its goal of obtaining spectrophotometry to a zero point accuracy of 0.01 mag, and down to V = 21 with 0.3 mag random error. We fit the color-magnitude diagrams (CMDs) with Worthey's theoretical models. The net result is the excellent fit of the 4.0 Gyr, [Fe/H] = $-0.10$ model to our data, including a good fit to the main sequence (MS) turn-off. Our data are consistent with a toy model with 50\% of the stars in M67 being binaries and a random distribution of binary mass-ratios, although other models with different mass-ratio distributions cannot be ruled out. The spatial distribution and mass function (MF) of stars in M67 show marked effects of dynamical evolution and evaporation of stars from the cluster. Blue stragglers and binary stars are the most condensed within the cluster, with degree of condensation depending on mass.We find M67 to have an elongated shape, oriented at an angle of $15^{\circ}$ relative to the galactic plane. Within its tidal radius, the observed MF of M67 between 1.2 $\rm M_\odot$ and $\rm 0.8 M_\odot$ has a Salpeter slope $\rm \eta = -1.93 \pm 0.66$. For stars of mass below 0.8 $\rm M_\odot$, $\rm \eta \sim 0$. It is plausible that the leveling-off of the MF at lower masses is a result of evaporation of lower mass stars in this mass range at a rate of one every $\sim 10^7$ years. If so, it is plausible that the IMF of M67 has the canonical field value of $\rm \eta = -2.0$.Comment: 74 pages, including 19 ps figures. Accepted for publication in AJ, Aug, 199

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