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We estimated 34 sets of Galactic model parameters for three intermediate latitude fields with Galactic longitudes l=60, l=90, and l=180, and we discussed their dependence on the volume. Also, we confirmed the variation of these parameters…

天体物理学 · 物理学 2009-11-13 S. Karaali , S. Bilir , E. Yaz , E. Hamzaoglu , R. Buser

We study the radial transport of cold gas within simulated disk galaxies at cosmic noon, aiming at distinguishing between disk instability and accretion along cold streams from the cosmic web as its driving mechanism. Disks are selected…

星系天体物理 · 物理学 2025-11-26 Dhruba Dutta Chowdhury , Avishai Dekel , Nir Mandelker , Omri Ginzburg , Reinhard Genzel

The problem of cosmic-ray scattering in the turbulent electromagnetic fields of the interstellar medium and the solar wind is of great importance due to the variety of applications of the resulting diffusion coefficients. Examples are…

高能天体物理现象 · 物理学 2015-05-20 R. C. Tautz

After the disappearance of lower energy heliospheric particles at Voyager 1 starting on August 25th, 2012, spectra of H, He and C/O nuclei were revealed that resembled those to be expected for galactic cosmic rays. These spectra had…

空间物理 · 物理学 2013-08-22 W. R. Webber , P. R. Higbie , F. B. McDonald

The kinematic dispersions of disc stars can be used to measure the dynamic contributions of baryons to the rotation curves of spiral galaxies and hence to trace the amount and distribution of the remaining dark matter. However, the simple…

星系天体物理 · 物理学 2017-05-31 Frederic V. Hessman

Diffuse interstellar clouds show large abundances of H_3^+ which can be maintained only by a high ionization rate of H_2. Cosmic rays are the dominant ionization mechanism in this environment, so the large ionization rate implies a high…

高能天体物理现象 · 物理学 2011-02-11 Nick Indriolo , Brian D. Fields , Benjamin J. McCall

We characterize empirically the radial diffusion of stars in the plane of a typical barred disk galaxy by calculating the local spatial diffusion coefficient and diffusion time-scale for bulge-disk-halo N-body self-consistent systems which…

星系天体物理 · 物理学 2015-05-30 Maura Brunetti , Cristina Chiappini , Daniel Pfenniger

Recently a cosmic ray propagation model has been introduced, where anisotropic diffusion is used as a mechanism to allow for $\mathcal{O}(100)$ km/s galactic winds. This model predicts a reduced antiproton background flux, suggesting an…

高能天体物理现象 · 物理学 2010-12-06 Phillip Grajek , Kaoru Hagiwara

We provide an empirical list of the Galactic dispersion measure ($DM_{Gal}$) contribution to the extragalactic fast radio bursts along 72 sightlines. It is independent of any model of the Galaxy, i.e., we do not assume the density of the…

星系天体物理 · 物理学 2020-11-04 Sanskriti Das , Smita Mathur , Anjali Gupta , Fabrizio Nicastro , Yair Krongold

The predicted central densities of dark matter halos in LCDM models exceed those observed in some galaxies. Weinberg & Katz argue that angular momentum transfer from a rotating bar in the baryonic disk can lower the halo density, but they…

天体物理学 · 物理学 2009-11-11 J. A. Sellwood

Here we present a kinematic study of the Galactic halo out to a radius of $\sim$ 60 kpc, using 4664 blue horizontal branch (BHB) stars selected from the SDSS/SEGUE survey, to determine key dynamical properties. Using a maximum likelihood…

星系天体物理 · 物理学 2012-12-04 Prajwal R. Kafle , Sanjib Sharma , Geraint F. Lewis , Joss Bland-Hawthorn

Cosmic rays fill up the entire volume of galaxies, providing an important source of heating and ionisation of the interstellar medium, and may play a significant role in the regulation of star formation and galactic evolution. Diffuse…

高能天体物理现象 · 物理学 2015-06-03 Troy A. Porter

The anisotropy parameter $\beta$ characterizes the extent to which orbits in stellar systems are predominantly radial or tangential, and is likely to constrain, for the stellar halo of the Milky Way, scenarios for its formation and…

星系天体物理 · 物理学 2020-08-06 Sarah A. Bird , Xiang-Xiang Xue , Chao Liu , Juntai Shen , Chris Flynn , Chengqun Yang

Observations of molecular clouds in the gamma ray domain provide us with a tool to study the distribution of cosmic rays in the Galaxy. This is because cosmic rays can penetrate molecular clouds, undergo hadronic interactions in the dense…

高能天体物理现象 · 物理学 2017-08-23 Stefano Gabici

With the discovery of gravitational waves (GWs), Active Galactic Nuclei (AGN) disks have emerged as an interesting environment for hosting a fraction of their sources. AGN disks are conducive to forming both long and short Gamma-Ray Bursts…

高能天体物理现象 · 物理学 2025-03-07 Hoyoung D. Kang , Rosalba Perna , Davide Lazzati , Yi-Han Wang

The hard X-ray (>2 keV) emission of the local and distant Universe as observed with the HEAO1-A2 experiment is reconsidered in the context of large scale cosmic structure. Using all-sky X-ray samples of AGN and galaxy clusters we remove the…

天体物理学 · 物理学 2009-10-31 C. A. Scharf , K. Jahoda , M. Treyer , O. Lahav , E. Boldt , T. Piran

The ambipolar carrier diffusion in bulk GaAs is studied by using an ultrafast pump-probe technique with a high spatial resolution. Carriers with a point-like spatial profile are excited by a tightly focused pump laser pulse. The…

材料科学 · 物理学 2011-02-08 Brian A. Ruzicka , Lalani K. Werake , Hassana Samassekou , Hui Zhao

The AMS Collaboration has recently released precision data on cosmic ray (CR) leptons and protons at high energies. Interesting progresses have also been made on the measurement of CR nuclei, such as the boron-to-carbon ratio or the lithium…

高能天体物理现象 · 物理学 2015-11-02 Nicola Tomassetti

Convection is ubiquitous in stellar and planetary interiors where it likely plays an integral role in the generation of magnetic fields. As the interiors of these objects remain hidden from direct observation, numerical models of convection…

太阳与恒星天体物理 · 物理学 2026-01-22 Brandon J. Lazard , Nicholas A. Featherstone , Jonathan M. Aurnou

The propagation of charged particles, including cosmic rays, in a partially ordered magnetic field is characterized by a diffusion tensor whose components depend on the particle's Larmor radius $R_L$ and the degree of order in the magnetic…

高能天体物理现象 · 物理学 2016-03-04 A. P. Snodin , A. Shukurov , G. R. Sarson , P. J. Bushby , L. F. S. Rodrigues
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