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Physical Sciences and Mathematics Commons™
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Full-Text Articles in Physical Sciences and Mathematics
Ly Alpha Emission From Cosmic Structure. I. Fluorescence, Ja Kollmeier, Z Zheng, R Dave, A Gould, N Katz, J Miralda-Escude, Dh Weinberg
Ly Alpha Emission From Cosmic Structure. I. Fluorescence, Ja Kollmeier, Z Zheng, R Dave, A Gould, N Katz, J Miralda-Escude, Dh Weinberg
Astronomy Department Faculty Publication Series
We present predictions for the fluorescent Lyα emission signature arising from photoionized, optically thick structures in smoothed particle hydrodynamic cosmological simulations of a ΛCDM universe using a Monte Carlo Lyα radiative transfer code. We calculate the expected Lyα image and two-dimensional spectra for gas exposed to a uniform ultraviolet ionizing background as well as gas exposed additionally to the photoionizing radiation from a local quasar, after correcting for the self-shielding of hydrogen. As a test of our numerical methods and for application to current observations, we examine simplified analytic structures that are uniformly or anisotropically illuminated. We compare these results …
The Dearth Of Chemically Enriched Warm-Hot Circumgalactic Gas, Y Yao, Qd Wang, Sv Penton, Tm Tripp, Jm Shull, Jt Stocke
The Dearth Of Chemically Enriched Warm-Hot Circumgalactic Gas, Y Yao, Qd Wang, Sv Penton, Tm Tripp, Jm Shull, Jt Stocke
Astronomy Department Faculty Publication Series
The circumgalactic medium (CGM) around galaxies is believed to record various forms of galaxy feedback and contain a significant portion of the "missing baryons" of individual dark matter halos. However, clear observational evidence for the existence of the hot CGM is still absent. We use intervening galaxies along 12 background active galactic nuclei (AGNs) as tracers to search for X-ray absorption lines produced in the corresponding CGM. Stacking Chandra grating observations with respect to galaxy groups and different luminosities of these intervening galaxies, we obtain spectra with signal-to-noise ratios of 46-72 per 20 mÅ spectral bin at the expected O …
Pressure Support Versus Thermal Broadening In The Lyman Alpha Forest - I. Effects Of The Equation Of State On Longitudinal Structure, Ms Peeples, Dh Weinberg, R Dave, Ma Fardal, N Katz
Pressure Support Versus Thermal Broadening In The Lyman Alpha Forest - I. Effects Of The Equation Of State On Longitudinal Structure, Ms Peeples, Dh Weinberg, R Dave, Ma Fardal, N Katz
Astronomy Department Faculty Publication Series
In the low-density intergalactic medium that gives rise to the Lyman α (Lyα) forest, gas temperature and density are tightly correlated. The velocity scale of thermal broadening and the Hubble flow across the gas Jeans scale are of similar magnitude (HλJ∼σth). To separate the effects of gas pressure support and thermal broadening on the Lyα forest, we compare spectra extracted from two smoothed particle hydrodynamics simulations evolved with different photoionization heating rates (and thus different Jeans scales) and from the pressureless dark matter distribution, imposing different temperature–density relations on the evolved particle distributions. The …