Radiative transfer models of non-spherical prestellar cores
We present 2D Monte Carlo radiative transfer simulations of prestellar cores. We consider two types of asymmetry: disk-like asymmetry, in which the core is denser towards the equatorial plane than towards the poles; and axial asymmetry, in which the core is denser towards the south pole than the nor...
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ftunivcardiff:oai:https://orca.cardiff.ac.uk:47057 2023-05-15T18:23:19+02:00 Radiative transfer models of non-spherical prestellar cores Stamatelos, Dimitrios Whitworth, Anthony Peter Andre, P. Ward-Thompson, Derek 2004 application/pdf https://orca.cardiff.ac.uk/id/eprint/47057/ https://doi.org/10.1051/0004-6361:20034546 https://orca.cardiff.ac.uk/id/eprint/47057/1/Stamatellos%202004.pdf en eng EDP Sciences https://orca.cardiff.ac.uk/id/eprint/47057/1/Stamatellos%202004.pdf Stamatelos, Dimitrios https://orca.cardiff.ac.uk/view/cardiffauthors/A047953A.html, Whitworth, Anthony Peter https://orca.cardiff.ac.uk/view/cardiffauthors/A063408L.html orcid:0000-0002-1178-5486 orcid:0000-0002-1178-5486, Andre, P. and Ward-Thompson, Derek https://orca.cardiff.ac.uk/view/cardiffauthors/A071164T.html orcid:0000-0003-1140-2761 orcid:0000-0003-1140-2761 2004. Radiative transfer models of non-spherical prestellar cores. Astronomy & Astrophysics 420 (3) , pp. 1009-1023. 10.1051/0004-6361:20034546 https://doi.org/10.1051/0004-6361%3A20034546 file https://orca.cardiff.ac.uk/47057/1/Stamatellos%202004.pdf doi:10.1051/0004-6361:20034546 QB Astronomy Article PeerReviewed 2004 ftunivcardiff https://doi.org/10.1051/0004-6361:20034546 2022-10-27T22:35:45Z We present 2D Monte Carlo radiative transfer simulations of prestellar cores. We consider two types of asymmetry: disk-like asymmetry, in which the core is denser towards the equatorial plane than towards the poles; and axial asymmetry, in which the core is denser towards the south pole than the north pole. In both cases the degree of asymmetry is characterized by the ratio e between the maximum optical depth from the centre of the core to its surface and the minimum optical depth from the centre of the core to its surface. We limit our treatment here to mild asymmetries with $e = 1.5\,$ and $2.5\,$. We consider both cores which are exposed directly to the interstellar radiation field and cores which are embedded inside molecular clouds. The SED of a core is essentially independent of the viewing angle, as long as the core is optically thin. However, the isophotal maps depend strongly on the viewing angle. Maps at wavelengths longer than the peak of the SED (e.g. 850 $\mu$m) essentially trace the column-density. This is because at long wavelengths the emissivity is only weakly dependent on temperature, and the range of temperature in a core is small (typically $T_{\rm max}/T_{\rm min} \la 2$). Thus, for instance, cores with disk-like asymmetry appear elongated when mapped at 850 $\mu$m from close to the equatorial plane. However, at wavelengths near the peak of the SED (e.g. 200 $\mu$m), the emissivity is more strongly dependent on the temperature, and therefore, at particular viewing angles, there are characteristic features which reflect a more complicated convolution of the density and temperature fields within the core. These characteristic features are on scales 1/5 to 1/3 of the overall core size, and so high resolution observations are needed to observe them. They are also weaker if the core is embedded in a molecular cloud (because the range of temperature within the core is then smaller), and so high sensitivity is needed to detect them. Herschel, to be launched in 2007, will in principle provide the ... Article in Journal/Newspaper South pole Cardiff University: ORCA (Online Research @ Cardiff) South Pole North Pole |
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QB Astronomy Stamatelos, Dimitrios Whitworth, Anthony Peter Andre, P. Ward-Thompson, Derek Radiative transfer models of non-spherical prestellar cores |
topic_facet |
QB Astronomy |
description |
We present 2D Monte Carlo radiative transfer simulations of prestellar cores. We consider two types of asymmetry: disk-like asymmetry, in which the core is denser towards the equatorial plane than towards the poles; and axial asymmetry, in which the core is denser towards the south pole than the north pole. In both cases the degree of asymmetry is characterized by the ratio e between the maximum optical depth from the centre of the core to its surface and the minimum optical depth from the centre of the core to its surface. We limit our treatment here to mild asymmetries with $e = 1.5\,$ and $2.5\,$. We consider both cores which are exposed directly to the interstellar radiation field and cores which are embedded inside molecular clouds. The SED of a core is essentially independent of the viewing angle, as long as the core is optically thin. However, the isophotal maps depend strongly on the viewing angle. Maps at wavelengths longer than the peak of the SED (e.g. 850 $\mu$m) essentially trace the column-density. This is because at long wavelengths the emissivity is only weakly dependent on temperature, and the range of temperature in a core is small (typically $T_{\rm max}/T_{\rm min} \la 2$). Thus, for instance, cores with disk-like asymmetry appear elongated when mapped at 850 $\mu$m from close to the equatorial plane. However, at wavelengths near the peak of the SED (e.g. 200 $\mu$m), the emissivity is more strongly dependent on the temperature, and therefore, at particular viewing angles, there are characteristic features which reflect a more complicated convolution of the density and temperature fields within the core. These characteristic features are on scales 1/5 to 1/3 of the overall core size, and so high resolution observations are needed to observe them. They are also weaker if the core is embedded in a molecular cloud (because the range of temperature within the core is then smaller), and so high sensitivity is needed to detect them. Herschel, to be launched in 2007, will in principle provide the ... |
format |
Article in Journal/Newspaper |
author |
Stamatelos, Dimitrios Whitworth, Anthony Peter Andre, P. Ward-Thompson, Derek |
author_facet |
Stamatelos, Dimitrios Whitworth, Anthony Peter Andre, P. Ward-Thompson, Derek |
author_sort |
Stamatelos, Dimitrios |
title |
Radiative transfer models of non-spherical prestellar cores |
title_short |
Radiative transfer models of non-spherical prestellar cores |
title_full |
Radiative transfer models of non-spherical prestellar cores |
title_fullStr |
Radiative transfer models of non-spherical prestellar cores |
title_full_unstemmed |
Radiative transfer models of non-spherical prestellar cores |
title_sort |
radiative transfer models of non-spherical prestellar cores |
publisher |
EDP Sciences |
publishDate |
2004 |
url |
https://orca.cardiff.ac.uk/id/eprint/47057/ https://doi.org/10.1051/0004-6361:20034546 https://orca.cardiff.ac.uk/id/eprint/47057/1/Stamatellos%202004.pdf |
geographic |
South Pole North Pole |
geographic_facet |
South Pole North Pole |
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South pole |
genre_facet |
South pole |
op_relation |
https://orca.cardiff.ac.uk/id/eprint/47057/1/Stamatellos%202004.pdf Stamatelos, Dimitrios https://orca.cardiff.ac.uk/view/cardiffauthors/A047953A.html, Whitworth, Anthony Peter https://orca.cardiff.ac.uk/view/cardiffauthors/A063408L.html orcid:0000-0002-1178-5486 orcid:0000-0002-1178-5486, Andre, P. and Ward-Thompson, Derek https://orca.cardiff.ac.uk/view/cardiffauthors/A071164T.html orcid:0000-0003-1140-2761 orcid:0000-0003-1140-2761 2004. Radiative transfer models of non-spherical prestellar cores. Astronomy & Astrophysics 420 (3) , pp. 1009-1023. 10.1051/0004-6361:20034546 https://doi.org/10.1051/0004-6361%3A20034546 file https://orca.cardiff.ac.uk/47057/1/Stamatellos%202004.pdf doi:10.1051/0004-6361:20034546 |
op_doi |
https://doi.org/10.1051/0004-6361:20034546 |
_version_ |
1766202881964244992 |