On the Critical Ionization Velocity Effect in Interstellar Space and Possible Detection of Related Continuum Emission

Verschuur, Gerrit L.

doi:10.1109/tps.2007.898037

Cited by 4 publications

(4 citation statements)

References 28 publications

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“…This includes Draine & Lazarian (1998), Finkbeiner et al (2002), Schlegel et al (1998), and de Oliviera-Costa et al (2004). An alternative mechanism for producing low-density electrons possibly capable of generating high-frequency radio emission involves a plasma physical phenomenon suggested by Verschuur (2007).…”

Section: Discussionmentioning

confidence: 99%

“…Based on what is found in these examples, it is possible that where two H i features are interacting (colliding), current sheets are created in which particle acceleration may underlie the production of the continuum emission observed by WMAP. Excess electrons at these interfaces may initially be introduced through the process described by Verschuur (2007) and references therein.…”

Section: Discussionmentioning

confidence: 99%

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High Galactic Latitude Interstellar Neutral Hydrogen Structure and Associated (WMAP) High‐Frequency Continuum Emission

Verschuur

2007

ApJ

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Spatial associations have been found between interstellar neutral hydrogen ( H i) emission morphology and smallscale structure observed by the Wilkinson Microwave Anisotropy Probe (WMAP) in an area bounded by l ¼ 60 , 180and b ¼ 30 , 70 , which was the primary target for this study. This area is marked by the presence of highly disturbed local H i and a preponderance of intermediate-and high-velocity gas. The H i distribution toward the brightest peaks in the WMAP Internal Linear Combination (ILC) map for this area is examined, and by comparing with a second area on the sky it is demonstrated that the associations do not appear to be the result of chance coincidence. Close examination of several of the associations reveals important new properties of diffuse interstellar neutral hydrogen structure. In the case of the high-velocity cloud MI, the H i and WMAP ILC morphologies are similar, and an excess of soft X-ray emission and H emission have been reported for this feature. It is suggested that the small angular scale, highfrequency continuum emission observed by WMAP may be produced at the surfaces of H i features interacting one another, or at the interface between moving H i structures and regions of enhanced plasma density in the surrounding interstellar medium. It is possible that dust grains play a role in producing the emission. However, the primary purpose of this report is to draw attention to these apparent associations, without offering an unambiguous explanation as to the relevant emission mechanism(s).

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

High Galactic Latitude Interstellar Neutral Hydrogen Structure and Associated (WMAP) High‐Frequency Continuum Emission

Verschuur

2007

ApJ

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“…This is essentially identical to the value of 33.1±1.1 km s −1 in the present study. [The possible role of a mysterious plasma phenomenon known as the Critical Ionization Velocity effect in affecting the line widths of the broad components is discussed by Verschuur (2007b) and Verschuur & Schmelz (2010) and references therein. Further consideration of that poorly understood phenomenon is beyond the scope of the present study.]…”

Section: Sorting Gaussians Into Parameter Familiesmentioning

confidence: 99%

“…In three previous reports (Verschuur, 2007a: Paper 1;2007b;2010: Paper 2) 108 close associations between foreground galactic neutral hydrogen (HI) features and small-scale structures found in the Wilkinson Microwave Anisotropy Probe (WMAP) Internal Linear Combination (ILC) map of Hinshaw et al (2007) were listed. The latter structures are purported to have a cosmic origin while the former are features within the disk of the Milky Way relatively close to the Sun.…”

Section: Introductionmentioning

confidence: 99%

Interacting Galactic Neutral Hydrogen Filaments and Associated High-Frequency Continuum Emission

Verschuur

2013

ApJ

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Galactic HI emission profiles in an area where several large-scale filaments at velocities ranging from −46 km s −1 to 0 km s −1 overlap were decomposed into Gaussian components. Eighteen families of components defined by similarities of center velocity and line width were identified and related to small-scale structure in the high-frequency continuum emission observed by the WMAP spacecraft, as evidenced in the Internal Linear Combination (ILC) map of Hinshaw et al. (2007). When the center velocities of the Gaussian families, which summarize the properties of all the HI along the lines-of-sight in a given area, are used to focus on HI channel maps the phenomenon of close associations between HI and ILC peaks reported in previous papers is dramatically highlighted. Of particular interest, each of two pairs of HI peaks straddles a continuum peak. The previously hypothesized model for producing the continuum radiation (Verschuur, 2010) involving free-free emission from electrons is re-examined in the light of the new data. By choosing reasonable values for the parameters required to evaluate the model, the distance for associated HI−ILC features is of order 30 to 100 pc. No associated Hα radiation is expected because the electrons involved exist throughout the Milky Way. The mechanism for clumping and separation of neutrals and electrons needs to be explored.

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A Pervasive Broad Component in H I Emission Line Profiles: Temperature, Turbulence, or a Helium Signature?

Verschuur

Schmelz

2010

The Astronomical Journal

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On the Critical Ionization Velocity Effect in Interstellar Space and Possible Detection of Related Continuum Emission

Cited by 4 publications

References 28 publications

High Galactic Latitude Interstellar Neutral Hydrogen Structure and Associated (WMAP) High‐Frequency Continuum Emission

High Galactic Latitude Interstellar Neutral Hydrogen Structure and Associated (WMAP) High‐Frequency Continuum Emission

Interacting Galactic Neutral Hydrogen Filaments and Associated High-Frequency Continuum Emission

A Pervasive Broad Component in H I Emission Line Profiles: Temperature, Turbulence, or a Helium Signature?

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