Browsing by Author "Keel, W. C."
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Item The 2005 November outburst in OJ 287 and the binary black hole model(IOP Publishing, 2006-05-20) Valtonen, M. J.; Nilsson, K.; Sillanpaa, A.; Takalo, L. O.; Lehto, H. J.; Keel, W. C.; Haque, S.; Cornwall, D.; Mattingly, A.; University of Turku; University West Indies Mona Jamaica; University West Indies Saint Augustine; University of Alabama TuscaloosaWe report observations of the largest optical outburst in 20 years in the quasar OJ 287. In some ways it was expected, due to the well-known quasi-periodic 12 yr outburst cycle of OJ 287. In other ways the timing of the outburst was surprising, since calculations based on the periodicity were predicting such an outburst in late 2006. Here we point out that, in the precessing binary black hole model, first proposed by Sillanpaa et al., and later refined by Lehto & Valtonen and Sundelius et al., the precession shifts the first outburst of each outburst season progressively to earlier times relative to the mean period. Thus, in this model, the timing of the outburst is quite acceptable, even if it was not predicted. The next test of the model comes in 2007 September when the second brightness peak is due. It may then be possible to detect the shortening of the binary period due to emission of gravitational waves from the system.Item A collegiate approach: the instructor’s role in preparing students for collegiate trumpet study(University of Alabama Libraries, 2018) Covington, James Michael; Yates, Eric; University of Alabama TuscaloosaEffective pre-collegiate trumpet instruction is essential in preparing students for the first year of collegiate trumpet study. During the first year of college, students often find themselves overwhelmed with new demands and high expectations. By incorporating the teaching ideologies of American trumpet pedagogues Vincent Cichowicz, James Stamp, and William Adam, with a focus on the fundamental principles of trumpet playing, the pre-collegiate trumpet instructor can ease the transition to college. Through lesson organization, a learner-centered teaching approach, and correction of detrimental playing tendencies, the instructor can teach efficient practice concepts and organizational skills that will establish productive student practice routines and self-teaching skills. Furthermore, carefully selected trumpet literature can acclimate the student to common collegiate lesson assignments and performance requirements. With increasing competition in trumpet study, thoughtful and effective college preparation will lead to a productive collegiate trumpet study experience.Item Coupling semi-analytic models and N-body simulations: a new way of making galaxies and stellar halos(University of Alabama Libraries, 2017) McCord, Krista; Bailin, Jeremy; University of Alabama TuscaloosaStellar halos give insight into the initial conditions that existed when a host galaxy first formed and provide details on disrupted satellites via their different stellar populations. An algorithm that is computationally inexpensive compared to hydrodynamic simulations is necessary in order to theoretically study the structure and formation of galactic stellar halos in sufficient detail to probe substructure. CoSANG (Coupling Semi-Analytic/N-body Galaxies) is a new computational method that we are developing which couples pure dark matter N-body simulations with a semi-analytic galaxy formation model. At each timestep, results from the N-body simulation feed into the semi-analytic code, whose results feed back into the N-body code making the evolution of the dark matter and baryonic matter dependent on one another. CoSANG will enable a variety of galaxy formation science, including analysis of stellar populations, halo merging, satellite accretion, supermassive black holes, and indirect and direct dark matter detection. In this dissertation, I will describe the new simulation code CoSANG. The results from the extensive testing phase on CoSANG will be presented which indicate CoSANG is properly simulating feedback from galaxies within a dark matter halo. I used this validated code to analyze a CoSANG zoom simulation of a $10^{12} \mathrm{M_{\odot}}$ dark matter halo. Results showed a flatter inner halo near the disk and a more spherical outer halo which is expected when a galaxy exists at the center of a dark matter halo. A comparison is made with a simulation run with the same initial conditions, but with the baryonic component simulated using a hydrodynamic algorithm. The semi-analytic model predicted galaxy types better than the hydrodynamic simulation leading to the conclusion that the CoSANG halo is more accurate. I also present a dark matter direct detection analysis on the CoSANG zoom halo to measure the dark matter velocity distributions and modulation amplitudes. The CoSANG results show that the dark matter velocity distribution does not fit well to a Maxwell Boltzmann distribution and the modulation amplitudes derived indicate an anisotropic dark matter velocity distribution. Future work will include tagging dark matter particles with stellar properties to build and evolve a stellar halo.Item Dark matter decays from the galactic center using IceCube-86(University of Alabama Libraries, 2017) Pepper, James Alan; Williams, Dawn R.; University of Alabama TuscaloosaMost searches for Dark Matter primarily focus on the WIMP paradigm, which predicts dark matter masses in the GeV - 10 TeV range. However, these relatively low energy searches continue to produce null results, possibly suggesting that dark matter is something other than WIMPs. Gravitinos, on the other hand, can satisfy the cosmological constraints on dark matter, and decay with a lifetime orders of magnitude longer than the age of the universe, producing extremely high energy neutrinos. The IceCube Neutrino Observatory has already had success detecting EHE extragalactic neutrinos, and is well suited to search for dark matter in this high energy regime. This analysis sets limits on the gravitino lifetime from the high energy neutrino events observed at IceCube using three possible astrophysical explanations of the neutrino flux. The most conservative limit on the gravitino lifetime using the softest two-body decay mode was found to be $\tau_{DM} = 10^{27.6}s$. This is the first analysis developed to place a limit on the gravitino lifetime using IceCube software and simulation files, and the results are comparable to theoretical limits based on the same data set.Item Deep spectroscopy of the M-V similar to-14.8 host galaxy of a tidal disruption flare in A1795(Oxford University Press, 2014) Maksym, W. P.; Ulmer, M. P.; Roth, K. C.; Irwin, J. A.; Dupke, R.; Ho, L. C.; Keel, W. C.; Adami, C.; University of Alabama Tuscaloosa; Northwestern University; University of Michigan System; University of Michigan; Eureka Scientific; Peking University; Carnegie Institution for Science; UDICE-French Research Universities; Aix-Marseille UniversiteA likely tidal disruption of a star by the intermediate-mass black hole (IMBH) of a dwarf galaxy was recently identified in association with Abell 1795. Without deep spectroscopy for this very faint object, however, the possibility of a more massive background galaxy or even a disc-instability flare from a weak active galactic nucleus (AGN) could not be dismissed. We have now obtained 8 h of Gemini spectroscopy which unambiguously demonstrates that the host galaxy is indeed an extremely low mass (M-star similar to 3 x 10(8) M-circle dot) galaxy in Abell 1795, comparable to the least massive galaxies determined to host IMBHs via other studies. We find that the spectrum is consistent with the X-ray flare being due to a tidal disruption event rather than an AGN flare. We also set improved limits on the black hole mass (log[M-lozenge/M-circle dot] similar to 5.3-5.7) and infer a 15 yr X-ray variability of a factor of greater than or similar to 10(4). The confirmation of this galaxy-black hole system provides a glimpse into a population of galaxies that is otherwise difficult to study, due to the galaxies' low masses and intrinsic faintness, but which may be important contributors to the tidal disruption rate.Item Deep spectroscopy of the M-V similar to-14.8 host galaxy of a tidal disruption flare in A1795(Oxford University Press, 2014) Maksym, W. P.; Ulmer, M. P.; Roth, K. C.; Irwin, J. A.; Dupke, R.; Ho, L. C.; Keel, W. C.; Adami, C.; University of Alabama Tuscaloosa; Northwestern University; University of Michigan System; University of Michigan; Eureka Scientific; Peking University; Carnegie Institution for Science; UDICE-French Research Universities; Aix-Marseille UniversiteA likely tidal disruption of a star by the intermediate-mass black hole (IMBH) of a dwarf galaxy was recently identified in association with Abell 1795. Without deep spectroscopy for this very faint object, however, the possibility of a more massive background galaxy or even a disc-instability flare from a weak active galactic nucleus (AGN) could not be dismissed. We have now obtained 8 h of Gemini spectroscopy which unambiguously demonstrates that the host galaxy is indeed an extremely low mass (M-star similar to 3 x 10(8) M-circle dot) galaxy in Abell 1795, comparable to the least massive galaxies determined to host IMBHs via other studies. We find that the spectrum is consistent with the X-ray flare being due to a tidal disruption event rather than an AGN flare. We also set improved limits on the black hole mass (log[M-lozenge/M-circle dot] similar to 5.3-5.7) and infer a 15 yr X-ray variability of a factor of greater than or similar to 10(4). The confirmation of this galaxy-black hole system provides a glimpse into a population of galaxies that is otherwise difficult to study, due to the galaxies' low masses and intrinsic faintness, but which may be important contributors to the tidal disruption rate.Item The dependence of the A(V) prior for SN Ia on host mass and disc inclination(Oxford University Press, 2015) Holwerda, B. W.; Keel, W. C.; Kenworthy, M. A.; Mack, K. J.; Leiden University; Leiden University - Excl LUMC; University of Alabama Tuscaloosa; University of Melbourne; University of SydneyType Ia supernovae (SNe Ia) are used as 'standard candles' for cosmological distance scales. To fit their light-curve shape-absolute luminosity relation, one needs to assume an intrinsic colour and a likelihood of host galaxy extinction or a convolution of these, a colour distribution prior. The host galaxy extinction prior is typically assumed to be an exponential drop-off for the current supernova programmes (P(A(V)) proportional to e(-AV/tau 0)). We explore the validity of this prior using the distribution of extinction values inferred when two galaxies accidentally overlap (an occulting galaxy pair). We correct the supernova luminosity distances from the SDSS-III supernova projects (SDSS-SN) by matching the host galaxies to one of three templates from occulting galaxy pairs based on the host galaxy mass and the AV-bias-prior-scale (tau(0)) relation from Jha et al. We find that introducing an A(V) prior that depends on host mass results in lowered luminosity distances for the SDSS-SN on average but it does not reduce the scatter in individual measurements. This points, in our view, to the need for many more occulting galaxy templates to match to SN Ia host galaxies to rule out this possible source of scatter in the SN Ia distance measurements. We match occulting galaxy templates based on both mass and projected radius and we find that one should match by stellar mass first with radius as a secondary consideration. We discuss the caveats of the current approach: the lack of enough radial coverage, the small sample of priors (occulting pairs with HST data), the effect of gravitationally interacting as well as occulting pairs, and whether an exponential distribution is appropriate. Our aim is to convince the reader that a library of occulting galaxy pairs observed with HST will provide sufficient priors to improve (optical) SN Ia measurements to the next required accuracy in cosmology.Item Diffuse ionized regions in the vicinity of active galaxies(University of Alabama Libraries, 2011) Darnell, Erin Kay; Keel, W. C.; University of Alabama TuscaloosaUsing a sample of 39 Active Galactic Nuclei (AGN), we investigated the incidence of giant ionized clouds in the vicinity of active galaxies. We carried out remote observations of the sample using the Southeastern Association for Research in Astronomy (SARA) North telescope at Kitt Peak and the SARA South telescope on Cerro Tololo. Frames were taken in continuum V and using a narrowband filter that transmits the redshifted [O III] 5007 Å line. We formed an emission line image by subtracting the combined and scaled V frames from the combined [O III] frames. To reduce uncorrelated noise, the emission line images are median filtered with a 1".9 x 1".9 box size. To bring out large diffuse regions, we convolve the emission line image with a circular Gaussian function of 3".42 FWHM. Emergent structures are determined to be starlight or ionized gas. 21 members of our sample were recently shown to be tidally disrupted in an atomic Hydrogen (HI) study. No extended [O III]-line emission clouds were seen in the vicinity of any from this group. We found one new instance of extended ionized emission clouds near the Seyfert 1 galaxy RX J1103.2-0654.Item Dust mapping of spiral galaxy disks from the Hubble starsmog survey(University of Alabama Libraries, 2016) Bradford, Sarah; Keel, W. C.; University of Alabama TuscaloosaDust in spiral galaxy disks plays an important role in observations through its interaction with starlight. While arguments have been made in favor of completely opaque spiral disks as a result of the dust (see Valentijn, 1990), most subsequent studies agree that spiral galaxies include both optically thick and optically thin regions. Using the occulting-galaxies technique introduced by White & Keel (1992), we created transmission maps of nine partially overlapped galaxy systems taken from the STARSMOG (STarlight Absorption Reduction through a Survey of Multiple Occulting Galaxies) catalog to probe the optical depth in regions of backlit dust. The measurements of all nine targets show a wide range of opacities, and therefore none of them can be definitively classified as either "optically thick" or "optically thin". In the analysis of the transmission maps of predominantly highly inclined systems, we noticed a distinct edge to the dust structure beyond which no dust was present in the foreground galaxy disk. This radius varied amongst systems but was distinct enough to be measured for three of the systems. The transmission maps also reveal a web-like pattern to the dust structure in some galaxy disks. Four of the targets showed dust structure which not only followed the pitch angle of the spiral arms, but also crossed at other various angles. This web-like pattern was only observed in systems where the foreground galaxy was of Hubble type SBc/Sc/Sbc. While there appears to be no real trend in the statistics of transmission through backlit dust with respect to stellar mass of the galaxies, there does appear to be a correlation with respect to star formation rates. In this nine-system sample, the targets with the least star formation appear more opaque. By continuing this study for the rest of the STARSMOG targets, we will be able to determine how representative this sample is of the entire target set.Item AN EXTENDED DUST DISK IN A SPIRAL GALAXY: AN OCCULTING GALAXY PAIR IN THE ACS NEARBY GALAXY SURVEY TREASURY(IOP Publishing, 2009-02) Holwerda, B. W.; Keel, W. C.; Williams, B.; Dalcanton, J. J.; De Jong, R. S.; Space Telescope Science Institute; University of Alabama TuscaloosaWe present an analysis of an occulting galaxy pair, serendipitously discovered in the ACS Nearby Galaxy Survey Treasury observations of NGC 253 taken with the Hubble Space Telescope's (HST) Advanced Camera for Surveys in F475W, F606W, and F814W (SDSS-g, broad V, and I). The foreground disk system (at z <= 0.06) shows a dusty disk much more extended than the starlight, with spiral lanes seen in extinction out to 1.5 R(25), approximately 6 half-light radii. This pair is the first where extinction can be mapped reliably out to this distance from the center. The spiral arms of the extended dust disk show typical extinction values of A(F475W) similar to 0.25, A(F606W) similar to 0.25, and A(F814W) similar to 0.15. The extinction law inferred from these measures is similar to that of the local Milky Way, and we show that the smoothing effects of sampling at limited spatial resolution (< 57 pc, in these data) flattens the observed function through mixing of regions with different extinction. This galaxy illustrates the diversity of dust distributions in spirals, and the limitations of adopting a single dust model for optically similar galaxies. The ideal geometry of this pair of overlapping galaxies and the high sampling of HST data make this data set ideal to analyze this pair with three separate approaches to overlapping galaxies: (1) a combined fit, rotating copies of both galaxies, (2) a simple flip of the background image, and (3) an estimate of the original fluxes for the individual galaxies based on reconstructions of their proper isophotes. We conclude that in the case of high-quality data such as these, isophotal models are to be preferred.Item Finding fossil galaxy system progenitors using strong gravitational lensing(University of Alabama Libraries, 2018) Johnson, Lucas Edward; Irwin, Jimmy A.; University of Alabama TuscaloosaFossil galaxy systems have been described as some of the oldest systems in the universe, where the central galaxy has cannibalized most nearby member galaxies over cosmic time. While the progenitors to fossil systems have been predicted to exist in numerical simulations, little effort has gone into locating them until now. The discovery of fossil progenitors in the CASSOWARY catalog of strong gravitational lensing demonstrates that not all fossils are old, and their formation histories are more complex than originally thought. These progenitors have optical characteristics consistent with them being the transition phase between non-fossils and fossils, as we are observing the central galaxies in mid-assembly. We also identify a bias where systems acting as strong gravitational lenses are ~5 times more likely to be seen as fossils than non-lensing systems. Chandra X-ray images of eight CASSOWARY fossil progenitors show them being significantly over-luminous and hotter than comparable non-fossils which could be due to the strong lensing bias in our data, or fossils have characteristically deeper potential wells than non-fossils. Two progenitors were luminous enough to see a rise in gas temperature toward their cores which suggests these may be undergoing group mergers akin to the previously studied progenitor CSWA 2 verifying this as a viable fossil formation mechanism. Refinements to our original CASSOWARY data using the Hubble Space Telescope allowed us to disentangle complex merging environments at the centers of these eight progenitors, which further solidified the notion that progenitors are indeed transitioning toward fossil systems.Item The french connection: a pedagogical analysis of the trombone solo literature of the Paris Conservatory(University of Alabama Libraries, 2015) Carlson, Anthony Philip; Whitaker, Jonathan; University of Alabama TuscaloosaSelecting pedagogically sound and musically engaging solo literature for the developing trombone student is a major challenge. One of the most important sources for such repertoire is the collection of contest pieces composed over the last two centuries for the annual testing of students at the Paris Conservatory. These works remain among the most frequently performed in the solo trombone repertoire, and are important in trombone pedagogy. The first section of this manuscript includes an overview of the Paris Conservatory, the trombone professors who have taught there, and the annual instrumental contests held to examine the students. The second section examines the following contest works: Saint-Saëns’s Cavatine, Barat’s Andante et Allegro, Dutilleux’s Choral, Cadence, et Fugato, and Martin’s Ballade, addressing technical challenges and appropriate use in the developing trombone player’s course of studyItem Galaxy Zoo: building the low-mass end of the red sequence with local post-starburst galaxies(Oxford University Press, 2012) Wong, O. I.; Schawinski, K.; Kaviraj, S.; Masters, K. L.; Nichol, R. C.; Lintott, C.; Keel, W. C.; Darg, D.; Bamford, S. P.; Andreescu, D.; Murray, P.; Raddick, M. J.; Szalay, A.; Thomas, D.; VandenBerg, J.; Commonwealth Scientific & Industrial Research Organisation (CSIRO); Yale University; University of Alabama Tuscaloosa; University of Nottingham; Johns Hopkins University; Imperial College London; University of Oxford; University of PortsmouthWe present a study of local post-starburst galaxies (PSGs) using the photometric and spectroscopic observations from the Sloan Digital Sky Survey and the results from the Galaxy Zoo project. We find that the majority of our local PSG population have neither early- nor late-type morphologies but occupy a well-defined space within the colourstellar mass diagram, most notably, the low-mass end of the green valley below the transition mass thought to be the mass division between low-mass star-forming galaxies and high-mass passively evolving bulge-dominated galaxies. Our analysis suggests that it is likely that local PSGs will quickly transform into red, low-mass early-type galaxies as the stellar morphologies of the green PSGs largely resemble that of the early-type galaxies within the same mass range. We propose that the current population of PSGs represents a population of galaxies which is rapidly transitioning between the star-forming and the passively evolving phases. Subsequently, these PSGs will contribute towards the build-up of the low-mass end of the red sequence once the current population of young stars fade and stars are no longer being formed. These results are consistent with the idea of downsizing where the build-up of smaller galaxies occurs at later epochs.Item Hanny's Voorwerp Evidence of AGN activity and a nuclear starburst in the central regions of IC 2497(EDP Sciences, 2010) Rampadarath, H.; Garrett, M. A.; Jozsa, G. I. G.; Muxlow, T.; Oosterloo, T. A.; Paragi, Z.; Beswick, R.; van Arkel, H.; Keel, W. C.; Schawinski, K.; Leiden University; Leiden University - Excl LUMC; University of Manchester; Jodrell Bank Centre for Astrophysics; Swinburne University of Technology; University of Groningen; University of Alabama Tuscaloosa; Yale UniversityWe present high-and intermediate resolution radio observations of the central region in the spiral galaxy IC 2497, performed using the European VLBI Network (EVN) at 18 cm, and the Multi-Element Radio Linked Interferometer Network (MERLIN) at 18 cm and 6 cm. We detect two compact radio sources, with brightness temperatures above 10(5) K, suggesting that they are related to AGN activity. We show that the total 18 cm radio emission from the galaxy is dominated neither by these compact sources nor large-scale emission, but extended emission confined within a sub-kpc central region. IC 2497 therefore appears as a typical luminous infrared galaxy that exhibits a nuclear starburst with a massive star formation rate (M > 5 M(circle dot)) of 12.4 M(circle dot)/yr. These results are in line with the hypothesis that the ionisation nebula "Hanny's Voorwerp" at a distance of similar to 15-25 kpc from the galaxy is ionised by the radiation cone of the AGN.Item Investigating the effects of progenitor metallicity on observable features of chandrasekhar mass type ia supernovae and improving detonation models of sub-chandrasekhar mass type ia supernovae(University of Alabama Libraries, 2018) Miles, Broxton Jake; Townsley, Dean M.; University of Alabama TuscaloosaType Ia Supernovae are generally considered to be the result of the thermonuclear disruption of carbon oxygen white dwarfs. However, the exact mechanism behind the explosion remains uncertain. The pre-explosion progenitor of a white dwarf has never been observed, so all conclusions must be drawn from comparisons between observed events and computational models. Here, work is presented on identifying spectral features indicative of progenitor metallicity. Metallicity affects the production of alpha-chain elements, which leaves imprints in the spectra. Two features are found that may be signals of progenitor metallicity, a Ti feature at 4200 \AA\ and an Fe feature at 5500 \AA . The second portion of this work focuses on the accurate modeling of detonations in sub-Chandrasekhar mass type Ia supernovae. The scales of the burning processes involved, compared to the size of the white dwarf, make fully resolving the detonation computationally impossible in full-star simulations. To mitigate this problem, past studies have used sub-grid scale models that attempt to capture the energetics of the explosion and post-process the results to calculate their models' nucleosynthetic products. If sub-grid models are to be believed, they must have accurate treatments of detonation physics such as curvature and shock strengthening. In low-density regions of the white dwarf, the curvature of the detonation front slows its propagation, affecting the production of intermediate mass elements. We find that the sharp density gradient in the outer radii of the white dwarf counteracts the weakening effect of curvature, resulting in more complete burning than expected in this low density region.Item Landscapes, Series II by Traci Mendel: a pedagogical approach(University of Alabama Libraries, 2012) McGuire, John Patrick; Snead, Charles; University of Alabama TuscaloosaBecause there are limited resources that discuss how young horn players can approach contemporary music, this document offers a thorough examination of Landscapes, Series II by Traci Mendel. Inexperienced horn players may find this piece of contemporary music unapproachable unless they have the necessary knowledge to dissect the piece into manageable sections. For Landscapes, Series II, programmatic components provide information that is useful when interpreting the piece; a pedagogical analysis offers a phrase-by-phrase presentation. Through numerous interviews with the composer, as well as my own multiple experiences of extensively preparing Landscapes, Series II, I will show what an inexperienced horn player should focus on in order to successfully prepare this piece for performance. This will be achieved by first explaining the programmatic content as conveyed by the composer, so the performer has a firm concept of Mendel's artistic vision; then dissecting difficult rhythmic passages in order to aid with issues of ensemble; and finally through pedagogical suggestions for horn specific technical considerations that will aid in accurately relating the intent of the composer as well as efficiently and effectively executing extreme and nontraditional music for the horn.Item Mass dependent galaxy transformation mechanisms in the complex environment of SuperGroup Abell 1882(University of Alabama Libraries, 2013) Sengupta, Aparajita; Buta, Ronald James; University of Alabama TuscaloosaWe present our data and results from panchromatic photometry and optical spectrometry of the nearest (extremely rich) filamentary large scale structure, SuperGroup Abell 1882. It is a precursor of a cluster and is an inevitable part of the narrative in the study of galaxy transformations. There has been strong empirical evidence over the past three decades that galaxy environment affects galaxy properties. Blue disky galaxies transform into red bulge-like galaxies as they traverse into the deeper recesses of a cluster. However, we have little insight into the story of galaxy evolution in the early stages of cluster formation. Besides, in relaxed clusters that have been studied extensively, several evolutionary mechanisms take effect on similar spatial and temporal scales, making it almost impossible to disentangle different local and global mechanisms. A SuperGroup on the other hand, has a shallower dark-matter potential. Here, the accreting galaxies are subjected to evolutionary mechanisms over larger time and spatial scales. This separates processes that are otherwise superimposed in rich cluster-filament interfaces. As has been found from cluster studies, galaxy color and morphology tie very strongly with local galaxy density even in a complex and nascent structure like Abell 1882. Our major results indicate that there is a strong dependence of galaxy transformations on the galaxy masses themselves. Mass- dependent evolutionary mechanisms affect galaxies at different spatial scales. The galaxy color also varies with radial projected distance from the assumed center of the structure for a constant local galaxy density, indicating the underlying large scale structure as a second order evolutionary driver. We have looked for clues to the types of mechanisms that might cause the transformations at various mass regimes. We have found the thoroughly quenched low mass galaxies confined to the groups, whereas there are evidences of intermediate-mass quenched galaxies even in the far outskirts. However, unlike what we observe in this system, ideally would we expect the dwarf galaxies with their shallow potentials to be more vulnerable than more massive galaxies, and hence be quenched earlier. We propose harassment and/or ram-pressure stripping as the mechanism that might lead to the quenched galaxies near or inside the high density, high velocity dispersion region in and near the groups; and mergers as the mechanism for the intermediate mass quenched galaxies at the low density, low velocity dispersion outskirts. We also identify a starburst population preferentially occurring within the filaments, at least a subset of which must be progenitors of the quenched galaxies at the core of Abell 1882. This also indicates a higher degree of preprocessing within the filaments as compared to that of the field.Item A matter of coordination: a pedagogical study of respiration, slide placement, and articulation for the student trombonist and a synthesis of these processes for improved classroom instruction(University of Alabama Libraries, 2013) Faske, Bruce Edward; Snead, Charles; Whitaker, Jonathan; University of Alabama TuscaloosaThe execution of a single note on trombone is the result of a coordinated effort of three processes: respiration, slide placement, and articulation. These coordinated processes present the most significant hurdle for the developing trombonist. It is unrealistic for any classroom music teacher to be expected to understand the specific processes of the trombone, as the instruction found in music education instrumental methods courses is limited due to the time restraints of the semester. This document will serve as supplemental material to aid any instrumental teacher seeking insight into the unique challenges of trombone pedagogy in the classroom. This document is structured in two parts. Part One introduces examples of widely accepted pedagogical perspectives on respiration, slide placement, and articulation. Part Two draws upon the author's experience with public school band programs to provide examples for organizing the band room for successful classroom management, corrections for commonly used yet counterintuitive teaching instructions which hinder brass playing development, and author commentary on the most effective pedagogical perspectives and instructions for the information outlined in Part One.Item Measuring ultraviolet extinction with GALEX in overlapping galaxies(University of Alabama Libraries, 2011) Manning, Anna; Keel, W. C.; University of Alabama TuscaloosaDust in spiral galaxies is an all encompassing factor in star formation history, measurements of luminosity, and galaxy dynamics. To learn more about galaxy formation and the influence of dust, White & Keel 1992 formulated a direct method to estimate optical depth. In the past few years, with the aid of the Galaxy Zoo forum and its members, known as zooites, a scientifically acceptable number of galaxy pairs have been identified to create a full catalog for this particular research. The White & Keel 1992 method uses differential photometry which eliminates many of the errors that plague statistical techniques that rely on the internal structure of a galaxy to estimate optical depth. The method relies heavily on the symmetry of the galaxies that make up the pair. To fulfill the symmetry requirement of the ideal geometry, the most suitable pair consists of a foreground spiral backlit by an elliptical galaxy. As evidenced here, non-interacting visually symmetric galaxies pairs yield the best results. Observations at the WIYN telescope combined with exposures downloaded from the GALEX archive are used to estimate the optical depth in these pairs as outlined by White & Keel 1992 and additionally, to trace the star formation in UV detections. Two examples of extended dust far beyond the optical radius were observed and analyzed for extinction. In this sample of galaxies, the optical depth of each wavelength scaled to the B filter was generally constant across the wavelengths observed. The effects of clumpy dust structure in the spiral arms dominated the reddening law which likely resulted in an overestimate of the optical depth measurements.Item Multiwavelength selection of obscured agn and contributions to the X-ray background(University of Alabama Libraries, 2011) May, Branyon; Keel, W. C.; University of Alabama TuscaloosaObscuration in AGN is a crucial component to understanding the observed spectrum of the X-ray Background. We tested numerous AGN selection techniques in X-ray, mid-infrared, and optical to test for multiwavelength correlations and to help establish selection criteria for obscured AGN. With AGN sources dominating background X-ray sources, we selected medium-depth archival Chandra observations covering 5.6 deg^2 of sky and generating a large sample of serendipitous X-ray sources (greater than 10,000). The mid-infrared component came from archival Spitzer data, with ~3,500 sources being detected in at least two IRAC bands and 1,485 in all 4 bands. For the optical component, greater than 70% of the Chandra observations also had full coverage within the SDSS Data Release 7, >2,300 optical counterparts and 125 spectra. In analyzing the sample, we have identified the parameter spaces in the X-ray/mid-infrared/optical that are optimized for containing members of the elusive class of obscured AGN, and provide a candidate list. We cross-check our X-ray number counts and source densities with contributions to the X-ray background, and find that we resolve approximately 90% of the X-ray Background in the 0.5-8.0 keV range. Testing populations divided on X-ray hardness and flux-level confirms that the unresolved hard X-ray background will be dominated by large populations of increasingly fainter and harder sources.