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Full-Text Articles in Physical Sciences and Mathematics
Effects Of Gravitational Slip On The Higher-Order Moments Of The Matter Distribution, Scott F. Daniel
Effects Of Gravitational Slip On The Higher-Order Moments Of The Matter Distribution, Scott F. Daniel
Dartmouth Scholarship
Cosmological departures from general relativity offer a possible explanation for the cosmic acceleration. To linear order, these departures (quantified by the model-independent parameter ϖ, referred to as a “gravitational slip”) amplify or suppress the growth of structure in the universe relative to what we would expect to see from a general relativistic universe lately dominated by a cosmological constant. As structures collapse and become more dense, linear perturbation theory is an inadequate descriptor of their behavior, and one must extend calculations to nonlinear order. If the effects of gravitational slip extend to these higher orders, we might expect to see …
Dust And The Type Ii-Plateau Supernova 2004et, R. Kotak, W. P. S. Meikle, D. Farrah, C. L. Gerardy, R. J. Foley, S. D. Van Dyk, C. Fransson, P. Lundqvist, J. Sollerman, R. Fesen
Dust And The Type Ii-Plateau Supernova 2004et, R. Kotak, W. P. S. Meikle, D. Farrah, C. L. Gerardy, R. J. Foley, S. D. Van Dyk, C. Fransson, P. Lundqvist, J. Sollerman, R. Fesen
Dartmouth Scholarship
We present mid-infrared (MIR) observations of the Type II-plateau supernova (SN) 2004et, obtained with the Spitzer Space Telescope between 64 and 1406 days past explosion. Late-time optical spectra are also presented. For the period 300-795 days past explosion, we argue that the spectral energy distribution (SED) of SN 2004et comprises (1) a hot component due to emission from optically thick gas, as well as free-bound radiation; (2) a warm component due to newly formed, radioactively heated dust in the ejecta; and (3) a cold component due to an IR echo from the interstellar-medium dust of the host galaxy, NGC 6946. …
Distance To The Sagittarius Dwarf Galaxy Using Macho Project Rr Lyrae Stars, Andrea Kunder, Brian Chaboyer
Distance To The Sagittarius Dwarf Galaxy Using Macho Project Rr Lyrae Stars, Andrea Kunder, Brian Chaboyer
Dartmouth Scholarship
We derive the distance to the northern extension of the Sagittarius (Sgr) dwarf spheroidal galaxy from 203 Sgr RR0 Lyrae stars found in the MACHO database. Their distances are determined differentially with respect to 288 Galactic bulge RR0 Lyrae stars also found in the MACHO data. We find a distance modulus difference of 2.41 mag at l = 5◦ and b =− 8◦ and that the extension of the Sgr galaxy toward the galactic plane is inclined toward us. Assuming R GC = 8 kpc, this implies the distance to these stars is (m − M) 0 = …
Dark Matter Scaling Relations And The Assembly Epoch Of Coma Early-Type Galaxies, J. Thomas, R. P. Saglia, R. Bender, D. Thomas, K. Gebhardt, J Magorrian, E. M. Corsini, G. Wegner
Dark Matter Scaling Relations And The Assembly Epoch Of Coma Early-Type Galaxies, J. Thomas, R. P. Saglia, R. Bender, D. Thomas, K. Gebhardt, J Magorrian, E. M. Corsini, G. Wegner
Dartmouth Scholarship
Axisymmetric, orbit-based dynamical models are used to derive dark matter scaling relations for Coma early-type galaxies. From faint to bright galaxies, halo core radii and asymptotic circular velocities increase. Compared to spirals of the same brightness, the majority of Coma early-type galaxies—those with old stellar populations—have similar halo core radii but more than two times larger asymptotic halo velocities. The average dark matter density inside 2 r eff decreases with increasing luminosity and is 6.8 times larger than in disk galaxies of the same B-band luminosity. Compared at the same stellar mass, dark matter densities in ellipticals are 13.5 …