Power-law models of totally anisotropic scattering
The interstellar scattering responsible for pulsar parabolic arcs, and for intraday variability of compact radio quasars, is highly anisotropic in some cases. We numerically simulate these observed phenomena using totally anisotropic, power-law models for the electron density fluctuations which caus...
| Main Authors: | , , |
|---|---|
| Format: | Journal Article |
| Published: |
Oxford University Press
2013
|
| Subjects: | |
| Online Access: | http://hdl.handle.net/20.500.11937/8456 |
| _version_ | 1848745663941050368 |
|---|---|
| author | Tuntsov, A. Bignall, Hayley Walker, M. |
| author_facet | Tuntsov, A. Bignall, Hayley Walker, M. |
| author_sort | Tuntsov, A. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The interstellar scattering responsible for pulsar parabolic arcs, and for intraday variability of compact radio quasars, is highly anisotropic in some cases. We numerically simulate these observed phenomena using totally anisotropic, power-law models for the electron density fluctuations which cause the scattering. By comparing our results to the scattered image of PSR B0834+06 and, independently, to dual-frequency light curves of the quasar PKS 1257−326, we constrain the nature of the scattering media on these lines of sight. We find that models with spectral indices slightly below β = 3, including the one-dimensional Kolmogorov model, are broadly consistent with both data sets. We confirm that a single physical model suffices for both sources, with the scattering medium simply being more distant in the case of B0834+06. This reinforces the idea that intraday variability and parabolic arcs have a common cause in a type of interstellar structure which, though obscure, is commonplace. However, the implied gas pressure fluctuations are large compared to typical interstellar pressures, and the magnetic stresses are much larger still. Thus while these scattering media may be commonplace, their underlying dynamics appear quite extraordinary. |
| first_indexed | 2025-11-14T06:20:57Z |
| format | Journal Article |
| id | curtin-20.500.11937-8456 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T06:20:57Z |
| publishDate | 2013 |
| publisher | Oxford University Press |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-84562017-09-13T14:37:01Z Power-law models of totally anisotropic scattering Tuntsov, A. Bignall, Hayley Walker, M. pulsars: individual: B0834+06 ISM: structure ISM: general scattering turbulence BL Lacertae objects: individual: PKS?1257-326 The interstellar scattering responsible for pulsar parabolic arcs, and for intraday variability of compact radio quasars, is highly anisotropic in some cases. We numerically simulate these observed phenomena using totally anisotropic, power-law models for the electron density fluctuations which cause the scattering. By comparing our results to the scattered image of PSR B0834+06 and, independently, to dual-frequency light curves of the quasar PKS 1257−326, we constrain the nature of the scattering media on these lines of sight. We find that models with spectral indices slightly below β = 3, including the one-dimensional Kolmogorov model, are broadly consistent with both data sets. We confirm that a single physical model suffices for both sources, with the scattering medium simply being more distant in the case of B0834+06. This reinforces the idea that intraday variability and parabolic arcs have a common cause in a type of interstellar structure which, though obscure, is commonplace. However, the implied gas pressure fluctuations are large compared to typical interstellar pressures, and the magnetic stresses are much larger still. Thus while these scattering media may be commonplace, their underlying dynamics appear quite extraordinary. 2013 Journal Article http://hdl.handle.net/20.500.11937/8456 10.1093/mnras/sts527 Oxford University Press fulltext |
| spellingShingle | pulsars: individual: B0834+06 ISM: structure ISM: general scattering turbulence BL Lacertae objects: individual: PKS?1257-326 Tuntsov, A. Bignall, Hayley Walker, M. Power-law models of totally anisotropic scattering |
| title | Power-law models of totally anisotropic scattering |
| title_full | Power-law models of totally anisotropic scattering |
| title_fullStr | Power-law models of totally anisotropic scattering |
| title_full_unstemmed | Power-law models of totally anisotropic scattering |
| title_short | Power-law models of totally anisotropic scattering |
| title_sort | power-law models of totally anisotropic scattering |
| topic | pulsars: individual: B0834+06 ISM: structure ISM: general scattering turbulence BL Lacertae objects: individual: PKS?1257-326 |
| url | http://hdl.handle.net/20.500.11937/8456 |