Scatter broadening of compact radio sources by the ionized intergalacticmedium: prospects for detection with Space VLBI and the SquareKilometre Array
We investigate the feasibility of detecting and probing various components of the ionized intergalactic medium (IGM) and their turbulent properties at radio frequencies through observations of scatter broadening of compact sources. There is a strong case for conducting targeted observations to resol...
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| Format: | Journal Article |
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Oxford University Press
2015
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| Online Access: | http://hdl.handle.net/20.500.11937/12024 |
| _version_ | 1848747963976777728 |
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| author | Koay, J. Macquart, Jean-Pierre |
| author_facet | Koay, J. Macquart, Jean-Pierre |
| author_sort | Koay, J. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We investigate the feasibility of detecting and probing various components of the ionized intergalactic medium (IGM) and their turbulent properties at radio frequencies through observations of scatter broadening of compact sources. There is a strong case for conducting targeted observations to resolve scatter broadening (where the angular size scales as ~ν−2) of compact background sources intersected by foreground galaxy haloes and rich clusters of galaxies to probe the turbulence of the ionized gas in these objects, particularly using Space very long baseline interferometry (VLBI) with baselines of 350 000 km at frequencies below 800 MHz. The sensitivity of the Square Kilometre Array (SKA) allows multifrequency surveys of interstellar scintillation (ISS) of ~100 μJy sources to detect or place very strong constraints on IGM scatter broadening down to ~1 μas scales at 5 GHz. Scatter broadening in the warm–hot component of the IGM with typical overdensities of ~30 cannot be detected, even with Space VLBI or ISS, and even if the outer scales of turbulence have an unlikely low value of ~1 kpc. None the less, intergalactic scatter broadening can be of the order of ~100 μas at 1 GHz and ~3 μas at 5 GHz for outer scales ~1 kpc, assuming a sufficiently high-source redshift that most sight-lines intersect within a virial radius of at least one galaxy halo (z >~ 0.5 and 1.4 for 10 10 and 10 11 M⊙ systems, following McQuinn 2014). Both Space VLBI and multiwavelength ISS observations with the SKA can easily test such a scenario, or place strong constraints on the outer scale of the turbulence in such regions. |
| first_indexed | 2025-11-14T06:57:30Z |
| format | Journal Article |
| id | curtin-20.500.11937-12024 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T06:57:30Z |
| publishDate | 2015 |
| publisher | Oxford University Press |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-120242017-09-13T14:53:52Z Scatter broadening of compact radio sources by the ionized intergalacticmedium: prospects for detection with Space VLBI and the SquareKilometre Array Koay, J. Macquart, Jean-Pierre cosmology: theory scattering intergalactic medium We investigate the feasibility of detecting and probing various components of the ionized intergalactic medium (IGM) and their turbulent properties at radio frequencies through observations of scatter broadening of compact sources. There is a strong case for conducting targeted observations to resolve scatter broadening (where the angular size scales as ~ν−2) of compact background sources intersected by foreground galaxy haloes and rich clusters of galaxies to probe the turbulence of the ionized gas in these objects, particularly using Space very long baseline interferometry (VLBI) with baselines of 350 000 km at frequencies below 800 MHz. The sensitivity of the Square Kilometre Array (SKA) allows multifrequency surveys of interstellar scintillation (ISS) of ~100 μJy sources to detect or place very strong constraints on IGM scatter broadening down to ~1 μas scales at 5 GHz. Scatter broadening in the warm–hot component of the IGM with typical overdensities of ~30 cannot be detected, even with Space VLBI or ISS, and even if the outer scales of turbulence have an unlikely low value of ~1 kpc. None the less, intergalactic scatter broadening can be of the order of ~100 μas at 1 GHz and ~3 μas at 5 GHz for outer scales ~1 kpc, assuming a sufficiently high-source redshift that most sight-lines intersect within a virial radius of at least one galaxy halo (z >~ 0.5 and 1.4 for 10 10 and 10 11 M⊙ systems, following McQuinn 2014). Both Space VLBI and multiwavelength ISS observations with the SKA can easily test such a scenario, or place strong constraints on the outer scale of the turbulence in such regions. 2015 Journal Article http://hdl.handle.net/20.500.11937/12024 10.1093/mnras/stu2268 Oxford University Press fulltext |
| spellingShingle | cosmology: theory scattering intergalactic medium Koay, J. Macquart, Jean-Pierre Scatter broadening of compact radio sources by the ionized intergalacticmedium: prospects for detection with Space VLBI and the SquareKilometre Array |
| title | Scatter broadening of compact radio sources by the ionized intergalacticmedium: prospects for detection with Space VLBI and the SquareKilometre Array |
| title_full | Scatter broadening of compact radio sources by the ionized intergalacticmedium: prospects for detection with Space VLBI and the SquareKilometre Array |
| title_fullStr | Scatter broadening of compact radio sources by the ionized intergalacticmedium: prospects for detection with Space VLBI and the SquareKilometre Array |
| title_full_unstemmed | Scatter broadening of compact radio sources by the ionized intergalacticmedium: prospects for detection with Space VLBI and the SquareKilometre Array |
| title_short | Scatter broadening of compact radio sources by the ionized intergalacticmedium: prospects for detection with Space VLBI and the SquareKilometre Array |
| title_sort | scatter broadening of compact radio sources by the ionized intergalacticmedium: prospects for detection with space vlbi and the squarekilometre array |
| topic | cosmology: theory scattering intergalactic medium |
| url | http://hdl.handle.net/20.500.11937/12024 |