[0704.1125] High Galactic latitude interstellar neutral hydrogen (HI) structure and associated acoustic-scale WMAP hot spots

 Authors: Gerrit L. Verschuur Abstract: Associations have been found between interstellar neutral hydrogen (HI) emission morphology and small-scale structure observed by the Wilkinson Microwave Anisotropy Probe (WMAP) in a Target Area bounded by l = 60 deg & 180 deg, b = 30 deg & 70 deg. This area is marked by the presence of highly disturbed local HI and a preponderance of intermediate- and high-velocity gas and it remains to be determined whether the claimed associations are a hallmark of the presence of the anomalous velocity gas. The HI distribution toward the 33 brightest WMAP peaks in the Target Area is examined and it is demonstrated that the associations do not appear to be the result of chance coincidence. Furthermore, several important properties of diffuse interstellar neutral hydrogen structure have been identified that might otherwise have been overlooked if it were not for the fact that the continuum data focused attention on certain areas of the HI sky. Some of the most dramatic associations are illustrated. It is suggested that continuum emission is produced at the interface between interacting (colliding) HI structures or at the interface between moving HI structures and regions of enhanced plasma density in the surrounding interstellar medium. In the case of high-velocity cloud MI, HI and WMAP are clearly associated and both excess soft X-ray emission and H-alpha emission have been reported at the same location. The primary purpose of this report is to draw attention to these associations in the hope that it will stimulate further research to identify the physical mechanism(s) responsible. [PDF]  [PS]  [BibTex]  [Bookmark]

Discussion related to specific recent arXiv papers
Richard Lieu
Posts: 11
Joined: November 27 2005
Affiliation: University of Alabama, Huntsville

[0704.1125] High Galactic latitude interstellar neutral hyd

I just posted this paper on astro-ph for Gerrit Verschuur,
whose findings were also read by me at the Imperial
College Outstanding questions' conference.

Another small and ignorable glitch' for the standard
cosmological model?

Note: while Rudnick et al were concerned with WMAP cold spots,
Verschuur's work is about many of the degree-scale hot spots.

Richard Lieu
Posts: 11
Joined: November 27 2005
Affiliation: University of Alabama, Huntsville

[0704.1125] High Galactic latitude interstellar neutral hy

I just gathered that this paper is seeing the light of day with its ApJ submission.

Two referee reports altogether. Both were favorably disposed with the work.
even though some more changes were called for.

Thus I urge you to READ carefully what Verschuur has to say! The claim here is
that a good fraction of the degree scale hot spots, hence the fluctuation power
in the first acoustic peak, is due to interaction between nearby Galactic HI clouds.

Kate Land
Posts: 29
Joined: September 27 2004
Affiliation: Oxford University
Contact:

[0704.1125] High Galactic latitude interstellar neutral hy

I have only skimmed through, but the main claim seems to be that there are correlations between galactic structure and the WMAP ILC map, on small scales. Therefore the ILC map (and power spectrum) may not be of cosmological origin.

This conclusion seems rather heavy and OTT - I'd rephrase it to there being evidence for galactic foreground contamination of the ILC map. However, perhaps this is not suprising considering that the WMAP team do not claim this map to be perfect, and in fact they say you should only use it for $\ell \lesssim 10$.

(Anyway, the significance of the correlation is another question...)

Richard Lieu
Posts: 11
Joined: November 27 2005
Affiliation: University of Alabama, Huntsville

[0704.1125] High Galactic latitude interstellar neutral hydr

I performed an extensive study (with B. Z. Jiang, a PhD
student of Prof. S.N. Zhang at Tsinghua, Beijing) using wavelet analysis
of the WMAP and HI data, then cross comparing the number of close associations between the degree-scale wavelet hot spot centroids and HI clouds with that expected from simulated WMAP data where the hot spot
locations are by definition randomized.

The verdict is that we found no statistically significant associations
between the first acoustic peak hot spots and HI. We therefore
cannot support the claim of Verschuur.