Associations between Scattering Screens and Interstellar Medium Filaments

Pulsar scintillation can be used to measure small-scale structure in the Galaxy, but little is known about the specific interstellar medium (ISM) features that cause scintillation. We searched for ISM counterparts to all scintillation screens for which absolute distances and scattering orientations...

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Main Authors: Ashley M. Stock, Marten H. van Kerkwijk
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
Subjects:
Online Access:https://doi.org/10.3847/1538-4357/ada1d8
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author Ashley M. Stock
Marten H. van Kerkwijk
author_facet Ashley M. Stock
Marten H. van Kerkwijk
author_sort Ashley M. Stock
collection DOAJ
description Pulsar scintillation can be used to measure small-scale structure in the Galaxy, but little is known about the specific interstellar medium (ISM) features that cause scintillation. We searched for ISM counterparts to all scintillation screens for which absolute distances and scattering orientations have been measured—a sample of 12 pulsars and 22 screens. For one pulsar, PSR J0737–3039A, we reanalyze its scintillation screen and find evidence for a highly anisotropic screen. Comparisons with tracers of ionized media did not find any new associations. Instead, for seven of the pulsars analyzed, aligned H  i filaments are seen for at least one of their screens, for a total of 12 out of 22 screens. This result seems unlikely to be due to chance: Comparing with random trials, we estimate a likelihood of finding 12 or more screens with aligned emission by chance of only 0.004%. Estimating the significance of the amount of aligned emission (in standard deviations over the mean), the probability of finding as much observed aligned emission by chance is larger, at 1.7%, but still indicative of a real correlation. Since H  i filaments are preferentially associated with cold neutral gas, and thus unlikely to cause scintillation, this may indicate that both the filaments and the screens are aligned preferentially by the same mechanisms, such as magnetic fields or shocks.
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spelling doaj-art-456a5a8d613647c1aeb0008530f067be2025-02-05T13:47:56ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198018010.3847/1538-4357/ada1d8Associations between Scattering Screens and Interstellar Medium FilamentsAshley M. Stock0https://orcid.org/0000-0001-5351-824XMarten H. van Kerkwijk1https://orcid.org/0000-0002-5830-8505David A. Dunlap Department of Astronomy & Astrophysics, University of Toronto , 50 Saint George Street, Toronto, ON M5S 3H4, Canada ; ashley.stock@mail.utoronto.ca; Canadian Institute for Theoretical Astrophysics, University of Toronto , 60 Saint George Street, Toronto, ON M5S 3H8, CanadaDavid A. Dunlap Department of Astronomy & Astrophysics, University of Toronto , 50 Saint George Street, Toronto, ON M5S 3H4, Canada ; ashley.stock@mail.utoronto.caPulsar scintillation can be used to measure small-scale structure in the Galaxy, but little is known about the specific interstellar medium (ISM) features that cause scintillation. We searched for ISM counterparts to all scintillation screens for which absolute distances and scattering orientations have been measured—a sample of 12 pulsars and 22 screens. For one pulsar, PSR J0737–3039A, we reanalyze its scintillation screen and find evidence for a highly anisotropic screen. Comparisons with tracers of ionized media did not find any new associations. Instead, for seven of the pulsars analyzed, aligned H  i filaments are seen for at least one of their screens, for a total of 12 out of 22 screens. This result seems unlikely to be due to chance: Comparing with random trials, we estimate a likelihood of finding 12 or more screens with aligned emission by chance of only 0.004%. Estimating the significance of the amount of aligned emission (in standard deviations over the mean), the probability of finding as much observed aligned emission by chance is larger, at 1.7%, but still indicative of a real correlation. Since H  i filaments are preferentially associated with cold neutral gas, and thus unlikely to cause scintillation, this may indicate that both the filaments and the screens are aligned preferentially by the same mechanisms, such as magnetic fields or shocks.https://doi.org/10.3847/1538-4357/ada1d8Interstellar scintillationPulsars
spellingShingle Ashley M. Stock
Marten H. van Kerkwijk
Associations between Scattering Screens and Interstellar Medium Filaments
The Astrophysical Journal
Interstellar scintillation
Pulsars
title Associations between Scattering Screens and Interstellar Medium Filaments
title_full Associations between Scattering Screens and Interstellar Medium Filaments
title_fullStr Associations between Scattering Screens and Interstellar Medium Filaments
title_full_unstemmed Associations between Scattering Screens and Interstellar Medium Filaments
title_short Associations between Scattering Screens and Interstellar Medium Filaments
title_sort associations between scattering screens and interstellar medium filaments
topic Interstellar scintillation
Pulsars
url https://doi.org/10.3847/1538-4357/ada1d8
work_keys_str_mv AT ashleymstock associationsbetweenscatteringscreensandinterstellarmediumfilaments
AT martenhvankerkwijk associationsbetweenscatteringscreensandinterstellarmediumfilaments