Pruning the Lyman alpha forest of Q1331+170

A multitude of absorption lines seen shortward of QSO Ly-alpha emission, that cannot be traced to heavy element absorption systems, are assumed to be Ly-alpha lines arising in intervening clouds. Studies of these Ly-alpha clouds, typically done at 1 A or lower resolution, have shown N(H1) approximately equal to 10(exp 13) - 10(exp 17) sq cm and b approximately equal to 35 km/s. Sargent et al 1980, on the basis of a flat pair velocity correlation function (PVCF), argued that these clouds are intergalactic. But Crotts 1989 showed that the strong Ly-alpha lines are spatially clustered. High resolution studies of Webb 1987 and Rauch et al 1992 also report some evidence for weak clustering, but overall such high resolution studies have been rare. A study of the Ly-alpha forest of Q1331 + 170 over x(sub abs) = 1.60 - 2.19 based on 18 km/s resolution data at S/N approximately equal to 15, with metal-line deblending incorporated

The impact of perceived forgiveness on the self-concept and spiritual well-being of inmates at the Ohio State Penitentiary correctional camp

https://place.asburyseminary.edu/ecommonsatsdissertations/1451/thumbnail.jp

A SINFONI Integral Field Spectroscopy Survey for Galaxy Counterparts to Damped Lyman-alpha Systems - IV. Masses and Gas Flows

The circumgalactic medium (CGM) of typical galaxies is crucial to our understanding of the cycling of gas into, through and out of galaxies. One way to probe the CGM is to study gas around galaxies detected via the absorption lines they produce in the spectra of background quasars. Here, we present medium resolution and new ~0.4-arcsec resolution (~3 kpc at z~1) 3D observations with VLT/SINFONI of galaxies responsible for high-N(HI) quasar absorbers. These data allow to determine in details the kinematics of the objects: the four z~1 objects are found to be rotation-supported as expected from inclined discs, while the fifth z~2 system is dispersion-dominated. Two of the systems show sign of interactions and merging. In addition, we use several indicators (star formation per unit area, a comparison of emission and absorption kinematics, arguments based on the inclination and the orientation of the absorber to the quasar line-of-sight and the distribution of metals) to determine the direction of the gas flows in and out of these galaxies. In some cases, our observations are consistent with the gas seen in absorption being due to material co-rotating with their halos. In the case of absorbing-galaxies towards Q1009-0026 and Q2222-0946, these indicators point toward the presence of an outflow traced in absorption.Comment: 18 pages, 11 figures, accepted for publication in MNRA

Diffuse Atomic and Molecular Gas in the Interstellar Medium of M82 toward SN 2014J

We present a comprehensive analysis of interstellar absorption lines seen in moderately-high resolution, high signal-to-noise ratio optical spectra of SN 2014J in M82. Our observations were acquired over the course of six nights, covering the period from ~6 days before to ~30 days after the supernova reached its maximum B-band brightness. We examine complex absorption from Na I, Ca II, K I, Ca I, CH+, CH, and CN, arising primarily from diffuse gas in the interstellar medium (ISM) of M82. We detect Li I absorption over a range in velocity consistent with that exhibited by the strongest Na I and K I components associated with M82; this is the first detection of interstellar Li in a galaxy outside of the Local Group. There are no significant temporal variations in the absorption-line profiles over the 37 days sampled by our observations. The relative abundances of the various interstellar species detected reveal that the ISM of M82 probed by SN 2014J consists of a mixture of diffuse atomic and molecular clouds characterized by a wide range of physical/environmental conditions. Decreasing N(Na I)/N(Ca II) ratios and increasing N(Ca I)/N(K I) ratios with increasing velocity are indicative of reduced depletion in the higher-velocity material. Significant component-to-component scatter in the N(Na I)/N(Ca II) and N(Ca I)/N(Ca II) ratios may be due to variations in the local ionization conditions. An apparent anti-correlation between the N(CH+)/N(CH) and N(Ca I)/N(Ca II) ratios can be understood in terms of an opposite dependence on gas density and radiation field strength, while the overall high CH+ abundance may be indicative of enhanced turbulence in the ISM of M82. The Li abundance also seems to be enhanced in M82, which supports the conclusions of recent gamma-ray emission studies that the cosmic-ray acceleration processes are greatly enhanced in this starburst galaxy.Comment: 32 pages, 6 figures, accepted to ApJ; added table giving single-epoch equivalent widths; improved discussion regarding the lack of temporal variations; improved analysis of the Li I regio

The Composite Spectrum of Strong Lyman-alpha Forest Absorbers

We present a new method for probing the physical conditions and metal enrichment of the Intergalactic Medium: the composite spectrum of Ly-alpha forest absorbers. We apply this technique to a sample of 9480 Ly-alpha absorbers with redshift 2 < z < 3.5 identified in the spectra of 13,279 high-redshift quasars from the Sloan Digital Sky Survey (SDSS) Fifth Data Release (DR5). Absorbers are selected as local minima in the spectra with 2.4 < tau_Ly-alpha < 4.0; at SDSS resolution (~ 150km/s FWHM), these absorbers are blends of systems that are individually weaker. In the stacked spectra we detect seven Lyman-series lines and metal lines of O VI, N V, C IV, C III, Si IV, C II, Al II, Si II, Fe II, Mg II, and O I. Many of these lines have peak optical depths of < 0.02, but they are nonetheless detected at high statistical significance. Modeling the Lyman-series measurements implies that our selected systems have total H I column densities N_HI ~ 10^15.4cm-2. Assuming typical physical conditions rho / = 10, T = 10^4 - 10^4.5 K, and [Fe/H]= -2 yields reasonable agreement with the line strengths of high-ionization species, but it underpredicts the low-ionization species by two orders of magnitude or more. This discrepancy suggests that the low ionization lines arise in dense, cool, metal-rich clumps, present in some absorption systems.Comment: 7 pages, 4 figures, 1 table, accepted by ApJL, revisions mad

Research Agenda for Studying Open Source II: View Through the Lens of Referent Discipline Theories

In a companion paper [Niederman et al., 2006] we presented a multi-level research agenda for studying information systems using open source software. This paper examines open source in terms of MIS and referent discipline theories that are the base needed for rigorous study of the research agenda

A Research Agenda for Studying Open Source I: A Multi-Level Framework

This paper presents a research agenda for studying information systems using open source software A multi-level research model is developed at five discrete levels of analysis: (1) the artifact; (2) the individual; (3) the team, project, and community; (4) the organization; and (5) society. Each level is discussed in terms of key issues within the level. Examples are based on prior research. In a companion paper, [Niederman, et al 2006], we view the agenda through the lens of referent discipline theories