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The dynamical properties of spherically symmetric galaxy models, where a Jaffe (1983) stellar density profile is embedded in a total mass density decreasing as $r^{-3}$ at large radii, are presented. The orbital structure of the stellar…

星系天体物理 · 物理学 2019-10-02 L. Ciotti , A. Mancino , S. Pellegrini

We present a simple phenomenological model of star formation in galaxies that describes the process with a set of a few parameters. The star formation efficiency and the fraction of gas and metals ejected in outflows are assumed to be the…

天体物理学 · 物理学 2007-05-23 I. Ferreras , J. Silk

We consider an explosion at the center of a halo which forms at the intersection of filaments inside a cosmological pancake, a convenient test-bed model for galaxy formation. ASPH/P3M simulations reveal that such explosions are anisotropic.…

天体物理学 · 物理学 2009-11-06 Hugo Martel , Paul R. Shapiro

Supermassive black holes are now realized to exist in the centers of most galaxies. The recent discoveries of luminous quasars at redshifts higher than 6 require that these black holes were assembled already when the Universe was less than…

天体物理学 · 物理学 2009-11-07 H. -Th. Janka

We outline a scenario of galaxy formation in which the gas in galaxy-forming regions was preheated to high entropy by vigorous energy feedback associated with the formation of stars in old ellipticals and bulges and with AGN activity. Such…

天体物理学 · 物理学 2016-08-30 H. J. Mo , S. Mao

The particles of a dark matter due to gravitational interaction deviate from straight trajectories in the vicinity of a massive body. This causes their density to become inhomogeneous. The developed density contrast causes a gravitation…

宇宙学与河外天体物理 · 物理学 2013-01-29 S. L. Parnovsky

Black holes (BHs) play a central role in physics. However, gathering observational evidence for their existence is a notoriously difficult task. Current strategies to quantify the evidence for BHs all boil down to looking for signs of…

广义相对论与量子宇宙学 · 物理学 2019-03-01 Tomohiro Harada , Vitor Cardoso , Daiki Miyata

We describe a mechanism by which supermassive black holes can form directly in the nuclei of protogalaxies, without the need for seed black holes left over from early star formation. Self-gravitating gas in dark matter halos can lose…

天体物理学 · 物理学 2009-11-11 Mitchell C. Begelman , Marta Volonteri , Martin J. Rees

We shall study the formation of a particular class of regular black holes from the gravitational collapse of a massive star. The inside geometry is described by spatially flat Friedmann-Robertson-Walker metric and the stellar matter is…

广义相对论与量子宇宙学 · 物理学 2022-04-13 F. Shojai , A. Sadeghi , R. Hassannejad

N-body simulations and analytical calculations of the gravitational collapse in an expanding universe predict that halos should form with a diverging inner density profile, the cusp. There are some observational indications that the dark…

天体物理学 · 物理学 2009-11-06 Amr El-Zant , Isaac Shlosman , Yehuda Hoffman

With the help of a statistical parameter derived from optical spectra, we show that the current star formation rate of a galaxy, falling into a cluster along a supercluster filament, is likely to undergo a sudden enhancement before the…

天体物理学 · 物理学 2009-11-13 Scott C. Porter , Somak Raychaudhury , Kevin A. Pimbblet , Michael J. Drinkwater

We generalize the spherical collapse model for the formation of dark matter halos to apply in a universe with arbitrary positive cosmological constant. We calculate the critical condition for collapse of an overdense region and give exact…

天体物理学 · 物理学 2016-11-03 Ewa L. Lokas , Y. Hoffman

We present results of numerical modeling made for the galactic stellar and stellar-gas disk embedded in the spherical halo and bulge. The stellar disk is simulated by N-body system, the equations of hydrodynamics are solved by TVD-method.…

宇宙学与河外天体物理 · 物理学 2010-07-27 A. V. Khoperskov , S. S. Khrapov

Based on the formulated and proven similarity properties of cosmological models based on a statistical system of degenerate scalarly charged fermions, as well as the previously identified mechanism of scalar-gravitational instability of…

广义相对论与量子宇宙学 · 物理学 2023-12-04 Yu. G. Ignat'ev

We simulate the collapse of isolated dwarf galaxies using SPH + N-Body simulations including a physically motivated description of the effects of supernova feedback. As the gas collapses and stars form, the supernova feedback disrupts…

天体物理学 · 物理学 2009-11-13 G. S. Stinson , J. J. Dalcanton , T. Quinn , T. Kaufmann , J. Wadsley

Along with compacting baryon (neutron) spacing, two very important factors come into play at once: the lack of self-stabilization within a compact neutron star (NS) associated with possible black hole (BH) horizon appearance and the phase…

高能物理 - 唯象学 · 物理学 2009-06-11 Ilya I. Royzen

Black holes are popping up all over the place: in compact binary X-ray sources and GRBs, in quasars, AGNs and the cores of all bulge galaxies, in binary black holes and binary black hole-neutron stars, and maybe even in the LHC! Black holes…

天体物理学 · 物理学 2007-11-13 Stuart L. Shapiro

The density irregularities and holes visible in many Chandra X-ray images of cluster and galactic cooling flows can be produced by symmetrically heated gas near the central galactic black hole. As the heated gas rises away from the galactic…

天体物理学 · 物理学 2009-11-07 Fabrizio Brighenti , William G. Mathews

The MBH - {\sigma}\ast relation has been studied extensively for local galaxies, but to date there have been scarce few direct measurements of stellar velocity dispersions for systems beyond the local universe. We investigate black hole and…

宇宙学与河外天体物理 · 物理学 2015-06-05 Kyle D. Hiner , Gabriela Canalizo , Margrethe Wold , Michael S. Brotherton , Sabrina L. Cales

Semi-analytic models of galaxy formation typically form the spheroidal components of galaxies ("bulges"), solely through galactic major mergers. However, it is possible that non-merger events (e.g. a "fly-by" by a smaller halo) can perturb…

宇宙学与河外天体物理 · 物理学 2016-07-07 Philip Bett