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

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We perform cosmological hydrodynamic simulations to determine to what extent galaxies lose their gas due to photoheating from an ionizing background. We find that the characteristic mass at which haloes on average have lost half of their…

Astrophysics · Physics 2008-10-31 Takashi Okamoto , Liang Gao , Tom Theuns

We study the structural evolution of turbulent molecular clouds under the influence of ionizing radiation emitted from a nearby massive star by performing a high resolution parameter study with the iVINE code. The temperature is taken to be…

Solar and Stellar Astrophysics · Physics 2015-05-19 Matthias Gritschneder , Andreas Burkert , Thorsten Naab , Stefanie Walch

We investigate the formation of molecular hydrogen (H_2) in a primordial H+He gas cloud irradiated by a power-law UV flux. We find that at high densities (>1 cm^{-3}) and low temperatures (<10^4 K), the background radiation enhances the…

Astrophysics · Physics 2009-10-28 Zoltan Haiman , Martin Rees , Abraham Loeb

We present a detailed calculation of the propagation of AGN-like ionizing radiation through the intergalactic space. We model the ionization state of absorbing clouds, and show that the universe will be more opaque above $4\,$Ryd than…

Astrophysics · Physics 2009-10-28 Francesco Haardt , Piero Madau

Recent observations have successfully detected UV or infrared flux from galaxies at the epoch of reionization. However, the origin of their radiative properties has not been fully understood yet. Combining cosmological hydrodynamic…

Astrophysics of Galaxies · Physics 2020-06-10 Shohei Arata , Hidenobu Yajima , Kentaro Nagamine , Yuexing Li , Sadegh Khochfar

We present a study of the ionization and thermal structure of neutral hydrogen clouds located in the Galactic halo, immersed in the extragalactic background radiation field, and supposed to be in pressure equilibrium with the surrounding…

Astrophysics · Physics 2009-10-22 Andrea Ferrara , George B. Field

We study the formation of H2 in the ISM, using a modified version of the astrophysical magnetohydrodynamical code ZEUS-MP that includes a non-equilibrium treatment of the formation and destruction of H2. We examine two different…

Astrophysics · Physics 2008-11-26 S. C. O. Glover , M. -M. Mac Low

Molecular clouds are supported by turbulence and magnetic fields, but quantifying their influence on cloud lifecycle and star formation efficiency (SFE) remains an open question. We perform radiation MHD simulations of star-forming giant…

Astrophysics of Galaxies · Physics 2021-05-05 Jeong-Gyu Kim , Eve C. Ostriker , Nina Filippova

The evolution of radiation emitted during the dynamical collapse of metal-free protostellar clouds is investigated within a spherically symmetric hydrodynamical scheme that includes the transfer of radiation and the chemistry of the…

Astrophysics · Physics 2009-11-06 Emanuele Ripamonti , Francesco Haardt , Andrea Ferrara , Monica Colpi

Our goal is to study the effects of the UV radiation from the first stars, quasars and hypothetical Super Heavy Dark Matter (SHDM) particle decays on the formation of primordial bound objects in the Universe. We trace the evolution of a…

Astrophysics · Physics 2015-06-24 Jaroslaw Stasielak , Slawomir Stachniewicz , Marek Kutschera

We demonstrate that the observationally inferred rapid onset of star formation after parental molecular clouds have assembled can be achieved by flow-driven cloud formation of atomic gas, using our previous three-dimensional numerical…

Astrophysics · Physics 2009-11-13 Fabian Heitsch , Lee Hartmann

The destruction of Giant Molecular Clouds is a key component in galaxy evolution. We theoretically model the destruction of GMCs by HII regions, which evaporate ionized gas and eject neutral gas during their expansion. HII regions follow…

Astrophysics of Galaxies · Physics 2025-11-05 David Hollenbach , Antonio Parravano , Christopher McKee

We have developed an accurate, one-dimensional, spherically symmetric, Lagrangian hydrodynamics/gravity code, designed to study the effects of radiative cooling and photo-ionization on the formation of protogalaxies. We examine the ability…

Astrophysics · Physics 2009-10-22 A. A. Thoul

Thermal and chemical evolution of primordial gas clouds irradiated with far-ultraviolet (FUV; < 13.6 eV) radiation is investigated. In clouds irradiated by intense FUV radiation, sufficient hydrogen molecules to be important for cooling are…

Astrophysics · Physics 2009-10-31 Kazuyuki Omukai

Molecular cloud structure is regulated by stellar feedback in various forms. Two of the most important feedback processes are UV photoionisation and supernovae from massive stars. However, the precise response of the cloud to these…

Astrophysics of Galaxies · Physics 2016-09-21 Sam Geen , Patrick Hennebelle , Pascal Tremblin , Joakim Rosdahl

We present semi-analytic dynamical models for giant molecular clouds evolving under the influence of HII regions launched by newborn star clusters. In contrast to previous work, we neither assume that clouds are in virial or energetic…

Astrophysics · Physics 2008-11-26 Mark R. Krumholz , Christopher D. Matzner , Christopher F. McKee

The EUV photoionizing radiation and FUV dissociating radiation from newly born stars photoevaporate their parental neutral cloud, leading to the formation of dense clumps that could eventually form additional stars. We study the effects of…

Solar and Stellar Astrophysics · Physics 2013-06-24 V. Lora , M. J. Vasconcelos , A. C. Raga , A. Esquivel , A. H. Cerqueira

Context. Molecular Clouds (MCs) are the place where stars are formed and their feedback starts to take place, regulating the evolution of galaxies. Therefore, MCs represent the critical scale at which to study how ultra-violet (UV) photons…

Astrophysics of Galaxies · Physics 2025-03-12 Fabio Di Mascia , Andrea Pallottini , Laura Sommovigo , Davide Decataldo

Recent suggestions of a "photon underproduction crisis" (Kollmeier \etal\ 2014) have generated concern over the intensity and spectrum of ionizing photons in the metagalactic ultraviolet background (UVB). The balance of hydrogen…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-23 J. Michael Shull , Joshua Moloney , Charles W. Danforth , Evan M. Tilton

Context. The seeds of the supermassive black holes (SMBHs) with masses of ~10^9 M_Sun observed already at z ~ 6 may have formed through the direct collapse of primordial gas in T_vir >~ 10^4 K halos, whereby the gas must stay hot (~10^4 K)…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-07 C. Van Borm , M. Spaans