Mathematics – Logic
Scientific paper
Jun 2006
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006phdt.........2s&link_type=abstract
Ph.D dissertation, 2006. Section 0058, Part 0606 170 pages; United States -- New York: Cornell University; 2006. Publication Num
Mathematics
Logic
3
Cosmological, Hydrogen, Galaxies, Mass Function
Scientific paper
We present a homogeneous compilation of HI spectral parameters extracted from global 21 cm line spectra for some 9000 galaxies in the local universe (heliocentric velocity -200 < [Special characters omitted.] < 28,000 km s -1 ) obtained with a variety of large single dish radio telescopes but reanalyzed using a single set of parameter extraction algorithms. Corrections to the observed HI line flux for source extent and pointing offsets and to the HI line widths for instrumental broadening and smoothing are applied according to model estimates to produce a homogenous catalog of derived properties with quantitative error estimates.
We exploit a complete optical diameter and HI flux limited subsample of this catalog to derive a robust measurement of the HI mass function (HIMF) for masses log( M HI /[Special characters omitted.] ) > 7.4 which takes into account the effects of local large scale structure. The global HIMF derived for this sample is well fit by a Schechter function with a = -1.24, log( M [low *] [Special characters omitted.] ) = 9.99, [straight phi] [low *] = 3.2 x 10 - 3 Mpc -3 . We also explore the possible environmental dependence of the HIMF by computing it separately in regimes of differing cosmic density. The HIMFs of higher density regions are found to have flatter low-mass ends and lower values of M [low *] than those of lower density regions, although the statistical significance of the difference is low.
We also present a compilation of Tully-Fisher distances and peculiar velocities, the SFI++, for a subset of the HI data that intersects with a separate compilation of optical photometry. Using this catalog, we examine the peculiar velocity field in and around the Pisces-Perseus Supercluster (PPS). We find that the PSC z velocity field provides a good fit to SFI++ in the PPS region, with no residual bulk flow along the line of sight and a best fit value of b of 0.33 +/- 0.16. While the quality of the fit is good, PSC z provides an even better fit to the all sky sample of SFI++, which gives b = 0.58 +/- 0.04. The difference in the values of b appears to stem from the lower correlation between observed and model velocities for the PPS subsample.
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