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

Abstract

Spatial associations have been found between interstellar neutral hydrogen (HI) emission morphology and small-scale structure observed by the Wilkinson Microwave Anisotropy Probe (WMAP) in an area bounded by l = 60 & 180 deg, b = 30 & 70 deg, which was the primary target for this study. This area is marked by the presence of highly disturbed local HI and a preponderance of intermediate- and high-velocity gas. The HI 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 high-velocity cloud MI, the HI and WMAP ILC morphologies are similar and an excess of soft X-ray emission and H-alpha emission have been reported for this feature. It is suggested that the small angular-scale, high frequency continuum emission observed by WMAP may be produced at the surfaces of HI features interacting one another, or at the interface between moving HI 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).

Revised version of ApJ submission

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Cited by in corpus (10)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Galactic Foreground Emission
• Tests and problems of the standard model in Cosmology
• On the Apparent Associations between Interstellar Neutral Hydrogen Structure and (WMAP) High Frequency Continuum Emission
• Sky maps without anisotropies in the cosmic microwave background are a better fit to WMAP's uncalibrated time ordered data than the official sky maps
• The Kinetic Sunyaev-Zel'dovich effect of the Milky Way Halo
• Interacting Galactic Neutral Hydrogen Filaments and Associated High-Frequency Continuum Emission
• On the Critical Ionization Velocity Effect in Interstellar Space and Possible Detection of Related Continuum Emission
• On the existence of young embedded clusters at high Galactic latitude
• Light emission of very low density hydrogen excited by an extremely hot light source; applications in astrophysics
• Correlation Analysis between Tibet AS-$\gamma$ TeV Cosmic Ray and WMAP Nine-year Data