Publications (44)
Spectroscopy of PKS 0528-260: New Limits on CO Absorption and Emission
Jian Ge, Jill Bechtold, Constance Walker +2
We have obtained a moderate resolution spectrum of the quasar PKS 0528-250 with the Red Channel Spectrograph on the Multiple Mirror Telescope (MMT) in order to study a damped Lyman…
Observational Constraints on the Dependence of Radio-Quiet Quasar X-ray Emission on Black Hole Mass and Accretion Rate
Brandon C. Kelly, Jill Bechtold, Jonathan R. Trump +2
In this work we use a sample of 318 radio-quiet quasars (RQQ) to investigate the dependence of the ratio of optical/UV flux to X-ray flux, alpha_ox, and the X-ray photon index, Gam…
A New Measurements of the Cosmic Microwave Background Radiation Temperature at z = 1.97
Jian Ge, Jill Bechtold, John H. Black
We present detections of absorption from the ground state and excited states of C I in the z = 1.9731 damped Ly\al\ system of the QSO 0013004. The excitation temperature between…
A uniform analysis of the Lyman alpha forest at z = 0-5: IV. The clustering and evolution of clouds at z < 1.7
Adam Dobrzycki, Jill Bechtold, Jennifer Scott +1
We present results on the evolution and clustering of Ly-alpha lines at low z. The sample contains 1298 Ly-alpha lines from 165 quasar spectra mined from the archives of the HST/FO…
A uniform analysis of the Lyman alpha forest at z = 0-5: III. HST FOS Spectral Atlas
Jill Bechtold, Adam Dobrzycki, Brenda Wilden +5
We analyzed the absorption line spectra of all quasars observed with the high resolution gratings of the Faint Object Spectrograph on board the Hubble Space Telescope. We examined…
The Size and Nature of Lyman alpha Forest Clouds Probed by QSO Pairs and Groups
Yihu Fang, Robert C. Duncan, Arlin P. S. Crotts +1
We describe a robust Bayesian statistical method for determining Lyman alpha forest cloud sizes in spherical and in thin disk geometries, using absorption in adjacent sightlines to…