Relativistic Ionization Fronts

dc.creatorShapiro, Paul R.
dc.creatorIliev, Ilian T.
dc.creatorAlvarez, Marcelo A.
dc.creatorScannapieco, Evan
dc.date2005-07-28
dc.date2006-05-30
dc.date.accessioned2026-07-07T10:43:16Z
dc.date.available2026-07-07T10:43:16Z
dc.descriptionWe derive the equations for the propagation of relativistic ionization fronts in both static and moving gases. We focus on the supersonic R-type phase that occurs right after a source turns on, and we compare the nonrelativistic and relativistic solutions for several important cases. Relativistic corrections can be significant up until the light-crossing time of the equilibrium Stromgren sphere. For a static medium, we obtain exact analytical solutions and apply them to the illustrative problems of an O star in a molecular cloud and a starburst in a high-redshift cosmological halo. Relativistic corrections can be important at early times when the H II regions are small, as well as at later times, if a density gradient causes the I-front to accelerate. For the cosmologically-expanding IGM, we derive an analytical solution in the case of a steady source and a constant clumping factor. Here relativistic corrections are significant for short-lived, highly-luminous sources like QSOs at the end of reionization, but negligible for weaker or higher-redshift sources. Finally, we numerically calculate the evolution of relativistic I-fronts in the presence of small-scale structure and infall, for a large galaxy undergoing a starburst and a luminous, high-redshift QSO. For such strong and short-lived sources, the relativistic corrections are quite significant, and small-scale structure can decrease the size of the H II region by up to an additional ~25%. (abridged)
dc.description18 pages, 7 figures, ApJ in print, resubmitted to match the accepted version, comments welcome
dc.identifierhttps://arxiv.org/abs/astro-ph/0507677
dc.identifierhttp://arxiv.org/abs/astro-ph/0507677
dc.identifierAstrophys.J.648:922-935,2006
dc.identifierdoi:10.1086/506242
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/182185
dc.subjectAstrophysics
dc.titleRelativistic Ionization Fronts
dc.typetext

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