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Related papers: Radiative feedback from an early X-ray background

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An X-ray background in the early Universe enhances molecular hydrogen formation, the main coolant of primordial gas, thereby lowering the threshold for Pop III star formation. Continuing our series on X-ray impacts on Pop III star…

Astrophysics of Galaxies · Physics 2026-03-30 Jongwon Park , Massimo Ricotti

In this paper, part of a series on the effects of X-ray sources in promoting Population III (Pop III) star formation, we investigate the ionisation and heating of the intergalactic medium (IGM) and the consequent enhancement of molecular…

Astrophysics of Galaxies · Physics 2026-03-30 Jongwon Park , Massimo Ricotti

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 examine aspects of primordial star formation in the presence of a molecular hydrogen-dissociating ultraviolet background. We compare a set of AMR hydrodynamic cosmological simulations using a single cosmological realization but with a…

Astrophysics · Physics 2009-11-13 Brian W. O'Shea , Michael L. Norman

We use three dimensional hydrodynamic simulations to investigate the effects of a soft X-ray background, that could have been produced by an early generation of mini-quasars, on the subsequent cooling and collapse of high redshift…

Astrophysics · Physics 2009-11-07 Marie M. Machacek , Greg L. Bryan , Tom Abel

In hierarchical models of structure formation, an early cosmic UV background (UVB) is produced by the small (T_vir < 10^4 K) halos that collapse before reionization. The UVB at energies below 13.6eV suppresses the formation of stars or…

Astrophysics · Physics 2016-08-30 Zoltan Haiman , Tom Abel , Martin J. Rees

We find that the amount and nature of the assumed ionizing background can strongly affect galaxy formation and evolution. Galaxy evolution simulations typically incorporate an ultraviolet background which falls off rapidly above z=3; e.g.,…

Astrophysics of Galaxies · Physics 2014-11-20 D. Clay Hambrick , Jeremiah P. Ostriker , Thorsten Naab , Peter H. Johansson

The first luminous objects forming in the universe produce radiation backgrounds in the FUV and X-ray bands that affect the formation of Population III stars. Using a grid of cosmological hydrodynamics zoom-in simulations, we explore the…

Astrophysics of Galaxies · Physics 2021-10-27 Jongwon Park , Massimo Ricotti , Kazuyuki Sugimura

Radiative feedback from populations II stars played a vital role in early structure formation. Particularly, photons below the Lyman limit can escape the star forming regions and produce a background ultraviolet (UV) flux which consequently…

Astrophysics of Galaxies · Physics 2015-06-19 M. A. Latif , D. R. G. Schleicher , S. Bovino , T. Grassi , M. Spaans

The formation of the first galaxies is influenced by the radiative feedback from the first generations of stars. This feedback is manisfested by the heating and ionization of the gas which lies within the H II regions surrounding the first…

Astrophysics · Physics 2010-11-05 Jarrett L. Johnson , Thomas H. Greif , Volker Bromm

Even though the dark-matter power spectrum in the absence of biasing predicts a number density of halos n(M) ~ M^-2 (i.e. a Schechter alpha value of -2) at the low-mass end (M < 10^10 M_solar), hydrodynamic simulations have typically…

Astrophysics of Galaxies · Physics 2015-05-20 D. C. Hambrick , J. P. Ostriker , P. H. Johansson , T. Naab

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

It is commonly believed that the earliest stages of star-formation in the Universe were self-regulated by global radiation backgrounds - either by the ultraviolet Lyman-Werner (LW) photons emitted by the first stars (directly…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Jemma Wolcott-Green , Zoltán Haiman

Ionizing UV radiation and supernova flows amidst clustered minihalos at high redshift regulated the rise of the first stellar populations in the universe. Previous studies have addressed the effects of very massive primordial stars on the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Daniel J. Whalen , Robert M. Hueckstaedt , Thomas McConkie

An ionizing UV background (UVB) inhibits gas accretion and photo-evaporates gas from the shallow potential wells of small, dwarf galaxies. During cosmological reionization, this effect can result in negative feedback: suppressing…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Emanuele Sobacchi , Andrei Mesinger

The first galaxies forming a few hundred million years after the Big Bang are the key drivers of cosmic evolution and ideal laboratories to study theories of galaxy formation. We here study the role of UV radiation in suppressing star…

Astrophysics of Galaxies · Physics 2019-10-16 Muhammad A. Latif , Sadegh Khochfar

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

We study the effect of starlight from the first stars on the ability of other minihaloes in their neighborhood to form additional stars. The question of what the dynamical consequences were for these target minihaloes, of their exposure to…

Astrophysics · Physics 2008-11-26 Kyungjin Ahn , Paul R. Shapiro

We investigate the impact of a cosmic X-ray background (CXB) on Population III stars forming in a minihalo at $z\simeq25$. Using the smoothed particle hydrodynamics code GADGET-2, we attain sufficient numerical resolution to follow gas…

Astrophysics of Galaxies · Physics 2015-09-30 Jacob A. Hummel , Athena Stacy , Myoungwon Jeon , Anthony Oliveri , Volker Bromm

We explore the impact of ultraviolet (UV) radiation from massive Population III (Pop III) stars of 25, 40, 80, and 120 M_sun on the subsequent Pop III star formation. In this paper, particular attention is paid to the dependence of…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-13 Kenji Hasegawa , Masayuki Umemura , Hajime Susa
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