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Physical Sciences and Mathematics Commons™
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Articles 1 - 4 of 4
Full-Text Articles in Physical Sciences and Mathematics
Structure Formation Inside Triaxial Dark Matter Halos: Galactic Disks, Bulges, And Bars, Clayton Heller, Isaac Shlosman, Evangelie Athanassoula
Structure Formation Inside Triaxial Dark Matter Halos: Galactic Disks, Bulges, And Bars, Clayton Heller, Isaac Shlosman, Evangelie Athanassoula
Department of Physics and Astronomy Faculty Publications
We investigate formation and evolution of galactic disks immersed in assembling live DM halos. Models have been evolved from cosmological initial conditions and represent the collapse of an isolated density perturbation. The baryons include gas participating in star formation (SF) and stars with the energy feedback onto the ISM. We find that (1) the triaxial halo figure tumbling is insignificant and the angular momentum (J) is channeled into the internal circulation, while the baryonic collapse is stopped by the centrifugal barrier; (2) density response of the (disk) baryons is out of phase with DM, thus washing out the …
Testing Thermal Reprocessing In Active Galactic Nuclei Accretion Discs, Edward M. Cackett, Keith Horne, Hartmut Winkler
Testing Thermal Reprocessing In Active Galactic Nuclei Accretion Discs, Edward M. Cackett, Keith Horne, Hartmut Winkler
Physics and Astronomy Faculty Research Publications
The thermal reprocessing hypothesis in active galactic nuclei (AGN), where extreme ultraviolet/X-ray photons are reprocessed by the accretion disc into optical/UV photons, predicts wavelength-dependent time-delays between the optical continuum at different wavelengths. Recent photometric monitoring by Sergeev et al. has shown that the time-delay is observed in 14 AGN, and generally seen to increase with increasing wavelength, as predicted in the reprocessing scenario. We fit the observed time-delays and optical spectral energy distribution using a disc reprocessing model. The model delivers estimates for the nuclear reddening, the product of black hole mass and accretion rate, and the distance to each …
Oases In The Dark: Galaxies As Probes Of The Cosmos, Shane L. Larson
Oases In The Dark: Galaxies As Probes Of The Cosmos, Shane L. Larson
Public Talks
No abstract provided.
Ngc 5548 In A Low-Luminosity State: Implications For The Broad-Line Region, Misty C. Bentz, Kelly D. Denney, Edward M. Cackett, Matthias Dietrich, Jeffery K. J. Fogel, Himel Ghosh, Keith Horne, Charles Kuehn, Takeo Minezaki, Christopher A. Onken, Bradley M. Peterson, Richard W. Pogge, Vladimir I. Pronik, Douglas O. Richstone, Sergey G. Sergeev, Marianne Vestergaard, Matthew G. Walker, Yuzuru Yoshii
Ngc 5548 In A Low-Luminosity State: Implications For The Broad-Line Region, Misty C. Bentz, Kelly D. Denney, Edward M. Cackett, Matthias Dietrich, Jeffery K. J. Fogel, Himel Ghosh, Keith Horne, Charles Kuehn, Takeo Minezaki, Christopher A. Onken, Bradley M. Peterson, Richard W. Pogge, Vladimir I. Pronik, Douglas O. Richstone, Sergey G. Sergeev, Marianne Vestergaard, Matthew G. Walker, Yuzuru Yoshii
Physics and Astronomy Faculty Research Publications
We describe results from a new ground-based monitoring campaign on NGC 5548, the best-studied reverberation-mapped AGN. We find that it was in the lowest luminosity state yet recorded during a monitoring program, namely L5100=4.7×1042 ergs s-1. We determine a rest-frame time lag between flux variations in the continuum and the Hβ line of 6.3+2.6-2.3 days. Combining our measurements with those of previous campaigns, we determine a weighted black hole mass of MBH=6.54+0.26-0.25×107 Msolar based on all broad emission lines with suitable variability data. We confirm the …