Structure of Stationary Photodissociation Fronts

Draine, B. T.; Bertoldi, F.

doi:10.1086/177689

Cited by 779 publications

(987 citation statements)

References 39 publications

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“…10 The Lyman-Werner radiation, which is responsible for H 2 photodissociation, is calculated based on emission from nearby stellar particles (Christensen et al 2012). H 2 is shielded from dissociating radiation through both self-shielding and dust shielding (Draine & Bertoldi 1996;Glover & Mac Low 2007;Gnedin et al 2009), using the smoothing lengths of particles for the column lengths. Similarly, H I is shielded from photoionizing radiation by dust.…”

Section: Simulation and Analysismentioning

confidence: 99%

In-N-Out: The Gas Cycle From Dwarfs to Spiral Galaxies

Christensen

Davé

Governato

et al. 2016

ApJ

211

250

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We examine the scalings of galactic outflows with halo mass across a suite of 20 high-resolution cosmological zoom galaxy simulations covering halo masses in the range - . These simulations self-consistently generate outflows from the available supernova energy in a manner that successfully reproduces key galaxy observables, including the stellar mass-halo mass, Tully-Fisher, and mass-metallicity relations. We quantify the importance of ejective feedback to setting the stellar mass relative to the efficiency of gas accretion and star formation. Ejective feedback is increasingly important as galaxy mass decreases; we find an effective mass loading factor that scales asv circ 2.2 , with an amplitude and shape that are invariant with redshift. These scalings are consistent with analytic models for energy-driven wind, based solely on the halo potential. Recycling is common: about half of the outflow mass across all galaxy masses is later reaccreted. The recycling timescale is typically ∼1 Gyr, virtually independent of halo mass. Recycled material is reaccreted farther out in the disk and with typically ∼2-3 times more angular momentum. These results elucidate and quantify how the baryon cycle plausibly regulates star formation and alters the angular momentum distribution of disk material across the halo mass range where most cosmic star formation occurs.

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Section: Simulation and Analysismentioning

confidence: 99%

In-N-Out: The Gas Cycle From Dwarfs to Spiral Galaxies

Christensen

Davé

Governato

et al. 2016

ApJ

211

250

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“…Draine & Bertoldi 1996;Abel et al 1997;Galli & Palla 1998a,b;Omukai 2001). However, the spectral energy distribution (SED) of stars shows a strong time dependence in its normalisation and shape at the relevant energies (e.g.…”

Section: H2 + γLw → H + H (3)mentioning

confidence: 99%

Revised rate coefficients for H2 and H− destruction by realistic stellar spectra

Agarwal

Khochfar

2014

Monthly Notices of the Royal Astronomical Society

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Understanding the processes that can destroy H 2 and H − species is quintessential in governing the formation of the first stars, black holes and galaxies. In this study we compute the reaction rate coefficients for H 2 photo-dissociation by Lyman-Werner photons (11.2 − 13.6 eV), and H − photo-detachment by 0.76 eV photons emanating from self-consistent stellar populations that we model using publicly available stellar synthesis codes. So far studies that include chemical networks for the formation of molecular hydrogen take these processes into account by assuming that the source spectra can be approximated by a power-law dependency or a black-body spectrum at 10 4 or 10 5 K. We show that using spectra generated from realistic stellar population models can alter the reaction rates for photo-dissociation, k di , and photo-detachment, k de , significantly. In particular, k de can be up to ∼ 2 − 4 orders of magnitude lower in the case of realistic stellar spectra suggesting that previous calculations have over-estimated the impact that radiation has on lowering H 2 abundances. In contrast to burst modes of star formation, we find that models with continuous star formation predict increasing k de and k di , which makes it necessary to include the star formation history of sources to derive self-consistent reaction rates, and that it is not enough to just calculate J 21 for the background. For models with constant star formation rate the change in shape of the spectral energy distribution leads to a non-negligible late-time contribution to k de and k di , and we present self-consistently derived cosmological reaction rates based on star formation rates consistent with observations of the high redshift Universe.

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“…Photodissociation and self-shielding of H 2 have been studied by Field et al (1966), Stecher and Williams (1967), ), Jura (1974, Black and Dalgarno (1977), Shull (1978), Federman et al (1979), van Dishoeck and Black (1986, Abgrall et al (1992), Heck et al (1992), LeBourlot et al (1995), and Lee et al (1996); the field has been reviewed by and recently discussed in detail by Draine and Bertoldi (1996). H 2 absorbs farultraviolet photons via Lyman and Werner electronic transitions in the 912-1100-Å range.…”

Section: H 2 Formation Destruction and Heatingmentioning

confidence: 99%

“…The photodissociation rate then depends on the H 2 abundance and level population distribution as a function of depth in the cloud. Various approximations, appropriate for chemical modeling, have been described by Jura (1974), Federman et al (1979), van Dishoeck and Black (1986), and Draine and Bertoldi (1996).…”

Section: H 2 Formation Destruction and Heatingmentioning

confidence: 99%

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Photodissociation regions in the interstellar medium of galaxies

Hollenbach

Tielens²

1999

Rev. Mod. Phys.

751

712

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The interstellar medium of galaxies is the reservoir out of which stars are born and into which stars inject newly created elements as they age. The physical properties of the interstellar medium are governed in part by the radiation emitted by these stars. Far-ultraviolet (6 eVϽh Ͻ13.6 eV) photons from massive stars dominate the heating and influence the chemistry of the neutral atomic gas and much of the molecular gas in galaxies. Predominantly neutral regions of the interstellar medium in which the heating and chemistry are regulated by far ultraviolet photons are termed PhotoDissociation Regions (PDRs). These regions are the origin of most of the non-stellar infrared (IR) and the millimeter and submillimeter CO emission from galaxies. The importance of PDRs has become increasingly apparent with advances in IR and submillimeter astronomy. The IR emission from PDRs includes fine structure lines of C, C ϩ , and O; rovibrational lines of H 2 ; rotational lines of CO; broad mid-IR features of polycyclic aromatic hydrocarbons; and a luminous underlying IR continuum from interstellar dust. The transition of H to H 2 and C ϩ to CO occurs within PDRs. Comparison of observations with theoretical models of PDRs enables one to determine the density and temperature structure, the elemental abundances, the level of ionization, and the radiation field. PDR models have been applied to interstellar clouds near massive stars, planetary nebulae, red giant outflows, photoevaporating planetary disks around newly formed stars, diffuse clouds, the neutral intercloud medium, and molecular clouds in the interstellar radiation field-in summary, much of the interstellar medium in galaxies. Theoretical PDR models explain the observed correlations of the [CII] 158 m with the CO Jϭ1 -0 emission, the CO Jϭ1 -0 luminosity with the interstellar molecular mass, and the [CII] 158 m plus [OI] 63 m luminosity with the IR continuum luminosity. On a more global scale, PDR models predict the existence of two stable neutral phases of the interstellar medium, elucidate the formation and destruction of star-forming molecular clouds, and suggest radiation-induced feedback mechanisms that may regulate star formation rates and the column density of gas through giant molecular clouds. [S0034-6861(99)01001-6] CONTENTS

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Structure of Stationary Photodissociation Fronts

Cited by 779 publications

References 39 publications

In-N-Out: The Gas Cycle From Dwarfs to Spiral Galaxies

In-N-Out: The Gas Cycle From Dwarfs to Spiral Galaxies

Revised rate coefficients for H2 and H− destruction by realistic stellar spectra

Photodissociation regions in the interstellar medium of galaxies

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