Principal Component analysis studies of turbulence in optically thick gas

In this work we investigate the sensitivity of principal component analysis (PCA) to the velocity power spectrum in high-opacity regimes of the interstellar medium (ISM). For our analysis we use synthetic position–position–velocity (PPV) cubes of fractional Brownian motion and magnetohydrodynamics (...

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Principais autores:	Correia, C., Lazarian, A., Burkhart, B., Pogosya, D., Medeiros, José Renan de
Formato:	article
Idioma:	English
Publicado em:	Sociedade Astronômica Americana
Assuntos:	Structure – magnetohydrodynamics
Endereço do item:	https://repositorio.ufrn.br/jspui/handle/123456789/29116
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spelling	ri-123456789-291162022-10-20T20:55:57Z Principal Component analysis studies of turbulence in optically thick gas Correia, C. Lazarian, A. Burkhart, B. Pogosya, D. Medeiros, José Renan de Structure – magnetohydrodynamics In this work we investigate the sensitivity of principal component analysis (PCA) to the velocity power spectrum in high-opacity regimes of the interstellar medium (ISM). For our analysis we use synthetic position–position–velocity (PPV) cubes of fractional Brownian motion and magnetohydrodynamics (MHD) simulations, post-processed to include radiative transfer effects from CO. We find that PCA analysis is very different from the tools based on the traditional power spectrum of PPV data cubes. Our major finding is that PCA is also sensitive to the phase information of PPV cubes and this allows PCA to detect the changes of the underlying velocity and density spectra at high opacities, where the spectral analysis of the maps provides the universal −3 spectrum in accordance with the predictions of the Lazarian & Pogosyan theory. This makes PCA a potentially valuable tool for studies of turbulence at high opacities, provided that proper gauging of the PCA index is made. However, we found the latter to not be easy, as the PCA results change in an irregular way for data with high sonic Mach numbers. This is in contrast to synthetic Brownian noise data used for velocity and density fields that show monotonic PCA behavior. We attribute this difference to the PCA's sensitivity to Fourier phase information. 2020-06-01T02:33:19Z 2020-06-01T02:33:19Z 2016 article CORREIA, C. ; LAZARIAN, A. ; BURKHART, B. ; POGOSYAN, D. ; MEDEIROS, J. R. de . Principal Component analysis studies os turbulence in optically thick gas. The Astrophysical Journal, v. 818, p. 118, 2016. Disponível em: http://iopscience.iop.org/article/10.3847/0004-637X/818/2/118/meta. Acesso em: 20 Maio 2020. http://dx.doi.org/10.3847/0004-637X/818/2/118 https://repositorio.ufrn.br/jspui/handle/123456789/29116 10.3847/0004-637X/818/2/118 en Sociedade Astronômica Americana
institution	Repositório Institucional
collection	RI - UFRN
language	English
topic	Structure – magnetohydrodynamics
spellingShingle	Structure – magnetohydrodynamics Correia, C. Lazarian, A. Burkhart, B. Pogosya, D. Medeiros, José Renan de Principal Component analysis studies of turbulence in optically thick gas
description	In this work we investigate the sensitivity of principal component analysis (PCA) to the velocity power spectrum in high-opacity regimes of the interstellar medium (ISM). For our analysis we use synthetic position–position–velocity (PPV) cubes of fractional Brownian motion and magnetohydrodynamics (MHD) simulations, post-processed to include radiative transfer effects from CO. We find that PCA analysis is very different from the tools based on the traditional power spectrum of PPV data cubes. Our major finding is that PCA is also sensitive to the phase information of PPV cubes and this allows PCA to detect the changes of the underlying velocity and density spectra at high opacities, where the spectral analysis of the maps provides the universal −3 spectrum in accordance with the predictions of the Lazarian & Pogosyan theory. This makes PCA a potentially valuable tool for studies of turbulence at high opacities, provided that proper gauging of the PCA index is made. However, we found the latter to not be easy, as the PCA results change in an irregular way for data with high sonic Mach numbers. This is in contrast to synthetic Brownian noise data used for velocity and density fields that show monotonic PCA behavior. We attribute this difference to the PCA's sensitivity to Fourier phase information.
format	article
author	Correia, C. Lazarian, A. Burkhart, B. Pogosya, D. Medeiros, José Renan de
author_facet	Correia, C. Lazarian, A. Burkhart, B. Pogosya, D. Medeiros, José Renan de
author_sort	Correia, C.
title	Principal Component analysis studies of turbulence in optically thick gas
title_short	Principal Component analysis studies of turbulence in optically thick gas
title_full	Principal Component analysis studies of turbulence in optically thick gas
title_fullStr	Principal Component analysis studies of turbulence in optically thick gas
title_full_unstemmed	Principal Component analysis studies of turbulence in optically thick gas
title_sort	principal component analysis studies of turbulence in optically thick gas
publisher	Sociedade Astronômica Americana
publishDate	2020
url	https://repositorio.ufrn.br/jspui/handle/123456789/29116
work_keys_str_mv	AT correiac principalcomponentanalysisstudiesofturbulenceinopticallythickgas AT lazariana principalcomponentanalysisstudiesofturbulenceinopticallythickgas AT burkhartb principalcomponentanalysisstudiesofturbulenceinopticallythickgas AT pogosyad principalcomponentanalysisstudiesofturbulenceinopticallythickgas AT medeirosjoserenande principalcomponentanalysisstudiesofturbulenceinopticallythickgas
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Principal Component analysis studies of turbulence in optically thick gas

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