%0 Generic %1 bisbas20123dpdr %A Bisbas, T. G. %A Bell, T. A. %A Viti, S. %A Yates, J. %A Barlow, M. J. %D 2012 %K code numerical pdr %T 3D-PDR: A new three-dimensional astrochemistry code for treating Photodissociation Regions %U http://arxiv.org/abs/1209.1091 %X Photodissociation regions (PDRs) define the transition zone between an ionized and a dark molecular region. They consist of neutral gas which interacts with far-ultraviolet radiation and are characterized by strong infrared line emission. Various numerical codes treating one-dimensional PDRs have been developed in the past, simulating the complexity of chemical reactions occurring and providing a better understanding of the structure of a PDR. In this paper we present the three-dimensional code, 3D-PDR, which can treat PDRs of arbitrary density distribution. The code solves the chemistry and the thermal balance self-consistently within a given three-dimensional cloud. It calculates the total heating and cooling functions at any point in a given PDR by adopting an escape probability method. It uses a HEALPix-based ray-tracing scheme to evaluate the attenuation of the far-ultraviolet radiation in the PDR and the propagation of the far-infrared/submm line emission out of the PDR. We present benchmarking results and apply 3D-PDR to i) a uniform-density spherical cloud interacting with a plane-parallel external radiation field, ii) a uniform-density spherical cloud interacting with a two-component external radiation field, and ii) a cometary globule interacting with a plane-parallel external radiation field. We find that the code is able to reproduce the benchmarking results of various other one-dimensional numerical codes treating PDRs. We also find that the accurate treatment of the radiation field in the fully three-dimensional treatment of PDRs can in some cases leads to different results when compared to a standard one-dimensional treatment.

@misc{bisbas20123dpdr, abstract = {Photodissociation regions (PDRs) define the transition zone between an ionized and a dark molecular region. They consist of neutral gas which interacts with far-ultraviolet radiation and are characterized by strong infrared line emission. Various numerical codes treating one-dimensional PDRs have been developed in the past, simulating the complexity of chemical reactions occurring and providing a better understanding of the structure of a PDR. In this paper we present the three-dimensional code, 3D-PDR, which can treat PDRs of arbitrary density distribution. The code solves the chemistry and the thermal balance self-consistently within a given three-dimensional cloud. It calculates the total heating and cooling functions at any point in a given PDR by adopting an escape probability method. It uses a HEALPix-based ray-tracing scheme to evaluate the attenuation of the far-ultraviolet radiation in the PDR and the propagation of the far-infrared/submm line emission out of the PDR. We present benchmarking results and apply 3D-PDR to i) a uniform-density spherical cloud interacting with a plane-parallel external radiation field, ii) a uniform-density spherical cloud interacting with a two-component external radiation field, and ii) a cometary globule interacting with a plane-parallel external radiation field. We find that the code is able to reproduce the benchmarking results of various other one-dimensional numerical codes treating PDRs. We also find that the accurate treatment of the radiation field in the fully three-dimensional treatment of PDRs can in some cases leads to different results when compared to a standard one-dimensional treatment.}, added-at = {2012-09-07T16:18:05.000+0200}, author = {Bisbas, T. G. and Bell, T. A. and Viti, S. and Yates, J. and Barlow, M. J.}, biburl = {https://www.bibsonomy.org/bibtex/2aa3375f0b57424d0782e5652527a7e3c/miki}, description = {[1209.1091] 3D-PDR: A new three-dimensional astrochemistry code for treating Photodissociation Regions}, interhash = {8a2cfbdc26b965b21fbff97e84e6f072}, intrahash = {aa3375f0b57424d0782e5652527a7e3c}, keywords = {code numerical pdr}, note = {cite arxiv:1209.1091Comment: 19 pages, 11 figures, accepted for publication in MNRAS}, timestamp = {2012-09-07T16:18:05.000+0200}, title = {3D-PDR: A new three-dimensional astrochemistry code for treating Photodissociation Regions}, url = {http://arxiv.org/abs/1209.1091}, year = 2012 }