T. B. Williams
Rutgers University
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Publication
Featured researches published by T. B. Williams.
The Astronomical Journal | 2000
Povilas Palunas; T. B. Williams
We present axisymmetric maximum disk mass models for a sample of 74 spiral galaxies taken from the southern sky Fabry-Perot Tully-Fisher survey by Schommer et al. The sample contains galaxies spanning a large range of morphologies and having rotation widths from 180 km s -1 to 680 km s -1. For each galaxy we have an I-band image and a two-dimensional Hα velocity field. We decompose the disk and bulge by fitting models directly to the I-band image. This method utilizes both the distinct surface brightness profiles and shapes of the projected disk and bulge in the galaxy images. The luminosity profiles and rotation curves are derived using consistent centers, position angles, and inclinations derived from the photometry and velocity maps. The distribution of mass is modeled as a sum of disk and bulge components with distinct, constant mass-to-light ratios. No dark matter halo is included in the fits. The models reproduce the overall structure of the rotation curves in the majority of galaxies, providing good fits to galaxies that exhibit pronounced structural differences in their surface brightness profiles. Of galaxies for which the rotation curve is measured to R23.5 or beyond 75% are well fitted by a mass-traces-light model for the entire region within R23.5. The models for about 20% of the galaxies do not fit well; the failure of most of these models is traced directly to nonaxisymmetric structures, primarily bars but also strong spiral arms. The median I-band M/L of the disk plus bulge is 2.4 ± 0.9 h75 in solar units, consistent with normal stellar populations. These results require either that the mass of dark matter within the optical disk of spiral galaxies is small or that its distribution is very precisely coupled to the distribution of luminous matter.
The Astronomical Journal | 1996
Benjamin J. Weiner; T. B. Williams
We have detected faint, diffuse H
The Astronomical Journal | 1993
Mario Hamuy; Jose Manuel Campillos Maza; Mark M. Phillips; Nicholas B. Suntzeff; M. Wischnjewsky; Ryan Christopher Smith; R. Antezana; Lisa A. Wells; L. E. González; P. Gigoux; M. Navarrete; Felipe Barrientos; R. Lamontagne; M. Della Valle; J. E. Elias; Andrew C. Phillips; S. C. Odewahn; J. A. Baldwin; Alistair R. Walker; T. B. Williams; Conrad R. Sturch; F. K. Baganoff; Brian Chaboyer; Robert A. Schommer; H. Tirado; M. Hernandez; P. Ugarte; Puragra Guhathakurta; Steve B. Howell; Paula Szkody
\alpha emission from several points along the Magellanic Stream, using the Rutgers Fabry--Perot Interferometer at the CTIO 1.5-m telescope. At points on the leading edges of the H I clouds MS II, MS III, and MS IV, we detect H
The Astronomical Journal | 2004
Kevin Krisciunas; Mark M. Phillips; Nicholas B. Suntzeff; S. E. Persson; Mario Hamuy; R. Antezana; Pablo Candia; Alejandro Clocchiatti; D. L. DePoy; Luis González; Sergio Gonzalez; Wojtek Krzeminski; Jose Manuel Campillos Maza; Peter E. Nugent; Y.-L. Qiu; Armin Rest; M. Roth; Maximilian D. Stritzinger; Louis-Gregory Strolger; Ian B. Thompson; T. B. Williams; M. Wischnjewsky
\alpha emission of surface brightness
The Astronomical Journal | 2007
A. S. Reese; T. B. Williams; J. A. Sellwood; Eric I. Barnes; Brian A. Powell
0.37 \pm 0.02
The Astronomical Journal | 1998
Paulina Lira; Nicholas B. Suntzeff; Mark M. Phillips; Mario Hamuy; Jose Manuel Campillos Maza; Robert A. Schommer; Ryan Christopher Smith; Lisa A. Wells; Roberto Aviles; J. A. Baldwin; Jonathan Elias; L. E. Gonzalez; Andrew C. Layden; M. Navarrete; P. Ugarte; Alistair R. Walker; Gerard M. Williger; F. K. Baganoff; Arlin P. S. Crotts; R. Michael Rich; Neil De Grasse Tyson; Arjun Dey; Puragra Guhathakurta; John E. Hibbard; Y.-C. Kim; Daniel M. Rehner; E. Siciliano; Joshua Roth; Patrick Seitzer; T. B. Williams
Rayleighs,
The Astronomical Journal | 2006
Arend P. N. Sluis; T. B. Williams
0.21 \pm 0.04
The Astronomical Journal | 1997
Paulina Lira; Mario Hamuy; Jonathan Elias; Jose Manuel Campillos Maza; M. Navarrete; Patrick Seitzer; Andrew C. Layden; Joshua Roth; John E. Hibbard; Y.-C. Kim; Neil De Grasse Tyson; F. K. Baganoff; Gerard M. Williger; Alistair R. Walker; Arjun Dey; Robert A. Schommer; Arlin P. S. Crotts; L. E. Gonzalez; Lisa A. Wells; Mark M. Phillips; Puragra Guhathakurta; Roberto Aviles; J. A. Baldwin; Ryan Christopher Smith; Nicholas B. Suntzeff; P. Ugarte; Daniel M. Rehner; E. Siciliano; T. B. Williams; R. Michael Rich
R, and
arXiv: Astrophysics | 2001
Benjamin J. Weiner; Stuart N. Vogel; T. B. Williams
0.20 \pm 0.02
arXiv: Astrophysics | 2000
Benjamin J. Weiner; Stuart N. Vogel; T. B. Williams
R respectively, corresponding to emission measures of 1.0 to 0.5 \cmsixpc. We have observed several positions near the MS IV concentration, and find that the strongest emission is on the sharp leading-edge density gradient. There is less emission at points away from the gradient, and halfway between MS III and MS IV the H