Quasars as Cosmological Probes: The Ionizing Continuum, Gas Metallicity
and the EW-L Relation
Korista, Kirk
1998-05-27
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148 records were found.
This article introduces a family of analytical functions of the form x^{\nu}
K_{\nu}(x), where K_{\nu} is the incomplete Bessel function of the third kind.
This family of functions can describe the density profile, projected and
integrated light profiles and the gravitational potentials of galaxies. For the
proper choice of parameters, these functions accurately approximate Sersic
functions over a range of indices and are good fits to galaxy light profiles.
With an additional parameter corresponding to a galaxy core radius, these
functions can fit galaxy like M87 over a factor of 100,000 in radius. Unlike
Sersic profiles, these functions have simple analytical 2-dimensional and
3-dimensional Fourier transforms, so they are easily convolved with spatially
varying point spread function and are well suited for photometric and lensing
an...
Comment: 13 pages, 8 figures
Comment: 19 pages, Latex, To appear in "Some Outstanding Questions in
Astrophysics", edited by J.N. Bahcall \& J.P. Ostriker
The Dwek et al. model represents the current state-of-the-art model for the stellar structure of our Galaxy. The improvements we have made to this model take a number of forms: (1) the construction of a more detailed dust model so that we can extend our modeling to the galactic plane; (2) simultaneous fits to the bulge and the disk; (3) the construction of the first self-consistent model for a galactic bar; and (4) the development and application of algorithms for constructing nonparametric bar models. The improved Galaxy model has enabled a number of exciting science projects. In Zhao et al., we show that the number and duration of microlensing events seen by the OGLE and MACHO collaborations towards the bulge were consistent with the predictions of our bar model. In Malhotra et al., we constructed an infrared Tully-Fisher (TF) relati...
This Letter presents an analytical model for the generation of density fluctuations likely to be appropriate for defects such as gauged and global strings, global monopoles, and textures, as well as for nontopological textures in an open or flat universe. For a reasonable range of parameters, these models in an open universe are compatible with both the level of MW fluctuations detected by COBE and with the fluctuations observed in the galaxy counts.
Comment: 5 pages, 2 figures, a bug in Fig.2 fixed
Comment: 8 pages; 7 figures
Comment: Rewritten and extended for Phys. Rev. D. Replaced with accepted
version
Comment: 13 pages, 5 figures, ApJ in press
Comment: 4 pages, 3 figures; v2 includes new plots illustrating the radial and
tangential velocities of non-debris particles
