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Full-Text Articles in Physical Sciences and Mathematics
Continuum And Spectral Line Radiation From A Random Clumpy Medium, John E. Conway, Moshe Elitzur, Rodrigo Para
Continuum And Spectral Line Radiation From A Random Clumpy Medium, John E. Conway, Moshe Elitzur, Rodrigo Para
Physics and Astronomy Faculty Publications
We present a formalism for continuum and line emission from random clumpy media together with its application to problems of current interest, including CO spectral lines from ensembles of clouds and radio emission from H ii regions, supernovae, and star-forming regions. For line emission, we find that the effects of clump opacity on observed line ratios can be indistinguishable from variations of intrinsic line strengths, adding to the difficulties in determining abundances from line observations. Our formalism is applicable to arbitrary distributions of cloud properties, provided the cloud volume filling factor is small; numerical simulations show it to hold up …
Challenges And Techniques For Simulating Line Emission, Karen P. Olsen, Andrea Pallottini, Aida Wofford, Marios Chatzikos, Mitchell Revalski, Francisco Guzmán, Gergö Popping, Enrique Vázquez-Semadeni, Georgios E. Magdis, Mark L. A. Richardson, Michaela Hirschmann, William J. Gray
Challenges And Techniques For Simulating Line Emission, Karen P. Olsen, Andrea Pallottini, Aida Wofford, Marios Chatzikos, Mitchell Revalski, Francisco Guzmán, Gergö Popping, Enrique Vázquez-Semadeni, Georgios E. Magdis, Mark L. A. Richardson, Michaela Hirschmann, William J. Gray
Physics and Astronomy Faculty Publications
Modeling emission lines from the millimeter to the UV and producing synthetic spectra is crucial for a good understanding of observations, yet it is an art filled with hazards. This is the proceedings of “Walking the Line”, a 3-day conference held in 2018 that brought together scientists working on different aspects of emission line simulations, in order to share knowledge and discuss the methodology. Emission lines across the spectrum from the millimeter to the UV were discussed, with most of the focus on the interstellar medium, but also some topics on the circumgalactic medium. The most important quality of a …
Molpop-Cep: An Exact, Fast Code For Multi-Level Systems, Andrés Asensio Ramos, Moshe Elitzur
Molpop-Cep: An Exact, Fast Code For Multi-Level Systems, Andrés Asensio Ramos, Moshe Elitzur
Physics and Astronomy Faculty Publications
We present MOLPOP-CEP, a universal line transfer code that allows the exact calculation of multi-level line emission from a slab with variable physical conditions for any arbitrary atom or molecule for which atomic data exist. The code includes error control to achieve any desired level of accuracy, providing full confidence in its results. Publicly available, MOLPOP-CEP employs our recently developed coupled escape probability (CEP) technique, whose performance exceeds other exact methods by orders of magnitude. The program also offers the option of an approximate solution with different variants of the familiar escape probability method. As an illustration of the MOLPOP-CEP …
Intermediate-Line Emission In Agns: The Effect Of Prescription Of The Gas Density, T. P. Adhikari, K. Hryniewicz, A. Różańska, B. Czerny, Gary J. Ferland
Intermediate-Line Emission In Agns: The Effect Of Prescription Of The Gas Density, T. P. Adhikari, K. Hryniewicz, A. Różańska, B. Czerny, Gary J. Ferland
Physics and Astronomy Faculty Publications
The requirement of an intermediate-line component in the recently observed spectra of several active galactic nuclei (AGNs) points to the possible existence of a physically separate region between the broad-line region (BLR) and narrow-line region (NLR). In this paper we explore the emission from the intermediate-line region (ILR) by using photoionization simulations of the gas clouds distributed radially from the center of the AGN. The gas clouds span distances typical for the BLR, ILR, and NLR, and the appearance of dust at the sublimation radius is fully taken into account in our model. The structure of a single cloud is …