136 citations · 690 across the 10 of their papers we have counts for
10 papers
Hot Gas Lines in T Tauri Stars
David R. Ardila, Gregory J. Herczeg, Scott G. Gregory +20
For Classical T Tauri Stars (CTTSs), the resonance lines of N V, Si IV, and C IV, as well as the He II 1640 A line, act as diagnostics of the accretion process. Here we assemble a…
NUV Excess in Slowly Accreting T Tauri Stars: Limits Imposed by Chromospheric Emission
Laura Ingleby, Nuria Calvet, Edwin Bergin +20
Young stars surrounded by disks with very low mass accretion rates are likely in the final stages of inner disk evolution and therefore particularly interesting to study. We presen…
Photoelectric cross-sections of gas and dust in protoplanetary disks
Thomas Bethell, Edwin Bergin
We provide simple polynomial fits to the X-ray photoelectric cross-sections (0.03 < E < 10keV) for mixtures of gas and dust found in protoplanetary disks. Using the solar elemental…
The propagation of Lyman-alpha in evolving protoplanetary disks
Thomas Bethell, Edwin Bergin
We study the role resonant scattering plays in the transport of Lyman-alpha photons in accreting protoplanetary disk systems subject to varying degrees of dust settling. While the…
The Far-Ultraviolet "Continuum" in Protoplanetary Disk Systems II: CO Fourth Positive Emission and Absorption
Kevin France, Rebecca Schindhelm, Eric B. Burgh +21
We exploit the high sensitivity and moderate spectral resolution of the -Cosmic Origins Spectrograph to detect far-ultraviolet spectral features of carbon monoxide (CO) presen…
Chemistry of a protoplanetary disk with grain settling and Lyman alpha radiation
Jeffrey K. J. Fogel, Thomas J. Bethell, Edwin A. Bergin +2
We present results from a model of the chemical evolution of protoplanetary disks. In our models we directly calculate the changing propagation and penetration of a high energy rad…
Polarization of Dust Emission in Clumpy Molecular Clouds and Cores
T. J. Bethell, A. Chepurnov, A. Lazarian +1
Grain alignment theory has reached the stage where quantitative predictions of the degree of alignment and its variations with optical depth are possible. With the goal of studying…
Estimating Column Density in Molecular Clouds with FIR and Sub-mm Emission Maps
S. Schnee, T. Bethell, A. Goodman
We have used a numerical simulation of a turbulent cloud to synthesize maps of the thermal emission from dust at a variety of far-IR and sub-mm wavelengths. The average column dens…
Dust heating by the interstellar radiation field in models of turbulent molecular clouds
Thomas Bethell, Ellen Zweibel, Fabian Heitsch +1
We have calculated the radiation field, dust grain temperatures, and far infrared emissivity of numerical models of turbulent molecular clouds. When compared to a uniform cloud of…
Linear Gas Dynamics in the Expanding Universe: Why the Jeans Scale does not Matter
Nickolay Y. Gnedin, Emily J. Baker, Thomas J. Bethell +9
We investigate the relationship between the dark matter and baryons in the linear regime. This relation is quantified by the so-called ``filtering scale''. We show that a simple ga…