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Related papers: Formation of Sub-galactic Clouds under UV Backgrou…

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To elucidate the effects of the UV background radiation on the collapse of pregalactic clouds, we implement a radiation-hydrodynamical calculation, combining one-dimensional spherical hydrodynamics with an accurate treatment of the…

Astrophysics · Physics 2009-10-31 T. Kitayama , Y. Tajiri , M. Umemura , H. Susa , S. Ikeuchi

The pancake collapse of pregalactic clouds under UV background radiation is explored with a one-dimensional sheet model. Here, attention is concentrated on elucidating the basic physics on the thermal evolution of pregalactic clouds exposed…

Astrophysics · Physics 2009-10-31 Hajime Susa , Masayuki Umemura

We use three-dimensional hydrodynamic simulations to investigate the effects of a transient photoionizing ultraviolet (UV) flux on the collapse and cooling of pregalactic clouds. These clouds have masses in the range 10^5 -10^7 M_sun, form…

Astrophysics · Physics 2008-11-26 Andrei Mesinger , Greg Bryan , Zoltan Haiman

We use high resolution N-body/gasdynamical simulations to investigate the effects of a photoionizing UV background on the assembly of disk galaxies in hierarchically clustering universes. We focus on the mass and rotational properties of…

Astrophysics · Physics 2009-10-28 Julio Navarro , Matthias Steinmetz

Photoionization by the high-redshift ultraviolet radiation background heats low density gas before it falls into dark matter potential wells, and it eliminates the neutral hydrogen and singly ionized helium that dominate cooling of…

Astrophysics · Physics 2011-08-17 Anne A. Thoul , David H. Weinberg

We present results from three-dimensional hydrodynamic simulations of the high redshift collapse of pregalactic clouds including feedback effects from a soft H2 photodissociating UV radiation field. The simulations use an Eulerian adaptive…

Astrophysics · Physics 2009-10-31 Marie E. Machacek , Greg L. Bryan , Tom Abel

The collapse of marginally Jeans unstable primordial gas clouds in the presence of UV radiation field is discussed. Assuming that the dynamical collapse proceeds approximately in an isothermal self-similar fashion, we investigate the…

Astrophysics · Physics 2009-10-31 Hajime Susa , Tetsu Kitayama

We investigate the effects of the observed UV background radiation on galaxy formation. Photoionization by UV radiation decreases the cooling rate of the gas in halos, so that objects with only large density contrasts can self-shield…

Astrophysics · Physics 2009-10-22 Masashi Chiba , Biman B. Nath

We present hydrodynamical simulations of the formation of galaxies in the mass range 10^9 - 10^13 solar masses, with the focus on the efficiency of gas cooling. The effect of a background UV radiation field, and the effect of metal…

Astrophysics · Physics 2007-05-23 John Hultman , Daniel Kaellander

We explore the impacts of ultraviolet (UV) radiation feedback on galaxies during the epoch of reionisation by cosmological simulations in which hydrodynamics and the transfer of the H and He ionising photons are consistently coupled.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Kenji Hasegawa , Benoit Semelin

To elucidate the permeation of cosmic ultraviolet (UV) background radiation into a pregalactic cloud and subsequent ionization, the frequency-dependent radiative transfer equation is solved, coupled with the ionization process. A spherical…

Astrophysics · Physics 2009-10-30 Yukiko Tajiri , Masayuki Umemura

We explore the possibility of the formation of globular clusters under ultraviolet (UV) background radiation. One-dimensional spherical symmetric radiation hydrodynamics (RHD) simulations by Hasegawa et al. have demonstrated that the…

Astrophysics of Galaxies · Physics 2016-09-21 Makito Abe , Masayuki Umemura , Kenji Hasegawa

We investigate the effects of the UV background radiation on galaxy formation by using the semi-analytic model including the photoionization process. The semi-analytic model is based on Cole et al. (1994) and we use almost the same…

Astrophysics · Physics 2009-10-30 Masahiro Nagashima , Naoteru Gouda , Norimasa Sugiura

Using 3D radiative transfer calculations on the reionization of an inhomogeneous universe, QSO absorption line systems are simulated and they are compared with observations of Ly$\alpha$ continuum depression at high redshifts. By this…

Astrophysics · Physics 2007-05-23 M. Umemura , T. Nakamoto , H. Susa

The estimate of the ionizing UV background through the proximity effect analysis is discussed. Taking into account the correct bending of the column density distribution which appears in high resolution high s/n data, a value of the UV…

Astrophysics · Physics 2007-05-23 E. Giallongo , S. Cristiani , S. D'Odorico , A. Fontana , S. Savaglio

We explore possibilities of collapse and star formation in Population III objects exposed to the external ultraviolet background (UVB) radiation. Assuming spherical symmetry, we solve self-consistently radiative transfer of photons,…

Astrophysics · Physics 2016-01-13 T. Kitayama , H. Susa , M. Umemura , S. Ikeuchi

I use a 1-D Lagrangian code which follows both a gaseous and a dark component to study the effects of a metagalactic UV background on the formation of dwarf galaxies. In the case of an ionising background consistent with the existing…

Astrophysics · Physics 2009-09-25 M. I. Forcada-Miro

It has been argued that a UV photoionizing background radiation field suppresses the formation of dwarf galaxies, and may even inhibit the formation of larger galaxies. In order to test this, we present gas-dynamical simulations of the…

Astrophysics · Physics 2016-06-08 Thomas Quinn , Neal Katz , George Efstathiou

We carry out a new suite of cosmological radiation hydrodynamic simulations and explore the relative impacts on reionization-epoch star formation of galactic outflows and photoionization heating. By itself, an extragalactic ultraviolet…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 K. Finlator , R. Davé , F. Özel

We present a novel scenario for globular cluster (GC) formation, where the ultraviolet (UV) background radiation effectively works so as to produce compact star clusters. Here, we explore the formation of GCs in UV radiation fields. For…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Kenji Hasegawa , Masayuki Umemura , Tetsu Kitayama
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