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Related papers: Photodissociation of H2 in Protogalaxies: Modeling…

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Population III stars can regulate star formation in the primordial Universe in several ways. They can ionize nearby halos, and even if their ionizing photons are trapped by their own halos, their Lyman-Werner (LW) photons can still escape…

Astrophysics of Galaxies · Physics 2015-10-21 Anna T. P. Schauer , Daniel J. Whalen , Simon C. O. Glover , Ralf S. Klessen

After the recombination of Hydrogen, primordial molecules such as H_2, $HD$ can be formed.The formation of structures in the post-recombination gaseous medium is commonly explained by primordial density fluctuations. In a self-gravitating…

Astrophysics · Physics 2007-05-23 D. Puy , M. Signore

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 investigate the dissociation equilibrium of $\rm H_2$ in very cool, helium-rich white dwarf atmospheres. We present the solution of the non-ideal chemical equilibrium for the dissociation of molecular hydrogen in a medium of dense…

Astrophysics · Physics 2009-11-13 Piotr M. Kowalski

Young massive stars produce Far-UV photons which dissociate the molecular gas on the surfaces of their parent molecular clouds. Of the many dissociation products which result from this ``back-reaction'', atomic hydrogen \HI is one of the…

Astrophysics · Physics 2016-01-27 Ronald J. Allen

A new collection of photodissociation and photoionisation cross sections for 102 atoms and molecules of astrochemical interest has been assembled, along with a brief review of the basic processes involved. These have been used to calculate…

Solar and Stellar Astrophysics · Physics 2017-06-28 A. N. Heays , A. D. Bosman , E. F. van Dishoeck

In massive primordial galaxies, the gas may directly collapse and form a single central massive object if cooling is suppressed. Line cooling by molecular hydrogen can be suppressed in the presence of a strong soft-ultraviolet radiation…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Dominik R. G. Schleicher , Marco Spaans , Simon C. O. Glover

Photodissociation Regions (PDRs) are key to understanding the feedback processes that shape interstellar matter in galaxies. One important type of PDR is the interface between HII regions and molecular clouds, where far-ultraviolet (FUV)…

We use numerical simulations to investigate the importance of HD formation and cooling on the first generation of metal-free stars in a LCDM cosmology. We have implemented and tested non-equilibrium HD chemistry in an adaptive mesh…

Astrophysics · Physics 2009-11-13 Ian D. McGreer , Greg L. Bryan

Methods: The microscopic equations of H2-formation and protonation are integrated numerically over time in such a manner that the overall structures evolve self-consistently under benign conditions. Results: The equilibrium H2 formation…

Astrophysics of Galaxies · Physics 2009-11-13 H. S. Liszt

Lyman-Werner (LW) radiation photodissociating molecular hydrogen (H$_2$) influences the thermal and dynamical evolution of the Population III (Pop III) star-forming gas cloud. The effect of powerful LW radiation has been well investigated…

Astrophysics of Galaxies · Physics 2023-11-20 Sho Nishijima , Shingo Hirano , Hideyuki Umeda

Cosmological hydrodynamic simulations predict the physical state of baryons in the circumgalactic medium (CGM), which can be directly tested via quasar absorption line observations. We use high resolution "zoom-in" simulations of 21…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Michele Fumagalli , Joseph F. Hennawi , J. Xavier Prochaska , Daniel Kasen , Avishai Dekel , Daniel Ceverino , Joel Primack

Motivated by the observed connection between molecular hydrogen (H2) and star formation, we present a method for tracking the non-equilibrium abundance and cooling processes of H2 and H2-based star formation in Smoothed Particle…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Charlotte Christensen , Thomas Quinn , Fabio Governato , Adrienne Stilp , Sijing Shen , James Wadsley

Photodissociation of 14N2 and 14N15N occurs in interstellar clouds, circumstellar envelopes, protoplanetary discs, and other environments due to UV radiation from stellar sources and the presence of cosmic rays. This source of N atoms…

We present models of CO(1-0) emission from Milky Way-mass galaxies at redshift zero in the FIRE-2 cosmological zoom-in simulations. We calculate the molecular abundances by post-processing the simulations with an equilibrium chemistry…

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

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

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

The environment around protoplanetary disks (PPDs) regulates processes which drive the chemical and structural evolution of circumstellar material. We perform a detailed empirical survey of warm molecular hydrogen (H$_2$) absorption…

Solar and Stellar Astrophysics · Physics 2017-08-30 Keri Hoadley , Kevin France , Nicole Arulanantham , R. O. Parke Loyd , Nicholas Kruczek

Population III stars are possible precursors to early massive and supermassive black holes (BHs). The presence of soft UV Lyman Werner (LW) background radiation can suppress Population III star formation in minihalos and allow them to form…

Astrophysics of Galaxies · Physics 2025-08-28 James Sullivan , Zoltan Haiman , Mihir Kulkarni , Eli Visbal