Astrophysics and Astronomy Commons^™

Taurus, Alex P. Tomaras

Natural Sciences Student Research Presentations

The constellation Taurus is featured in this poster for the Natural Sciences Poster Session at Parkland College. Work to complete this project included calculating a ear's time by looking at the stars and their movement, plotting a graph with the azimuth and altitude, and determining the life span of the constellations stars.

Orion, Eray Ergenc

Natural Sciences Student Research Presentations

This poster for the Natural Sciences Poster Session at Parkland College features the constellation Orion and features information on the composition of the stars, their distances and their mass in relation to each other. Art and its inclusion in Greek mythology are also included.

Leo, Andrew P. Woolley

Natural Sciences Student Research Presentations

The purpose of this project was to understand how information is gathered about stars, constellations, and galaxies, specifically the constellation Leo. Information gathered for this project includes how a star's position can be used to calculate the length of the year and how the mass and spectral type of a specific star can show when the star will die. This is a project for the Natural Sciences Poster Session at Parkland College

Higgs Effects In Neutrino Physics And Heavy Quark Systems, Ahmed Rashed

Electronic Theses and Dissertations

This work presents a study of the effects of multi-Higgs doublets on the properties of neutrino sector and heavy quark systems. The phenomenological implications of multi-Higgs models, which contain multi-Higgs doublets, in the neutrino and quark sector are discussed in this dissertation. The two-Higgs-doublet model (2HDM), in which two Higgs doublets are introduced, is the simplest extension to the scalar sector of the standard model (SM). A new boson state was recently seen in the CMS (Compact Muon Solenoid) and ATLAS (A Toroidal LHC Apparatus) experiments at the LHC (Large Hadron Collider). We investigate the multi-Higgs models contributions in understanding …

Cold Gas Dynamics In Hydra-A: Evidence For A Rotating Disc, S. L. Hamer, A. C. Edge, A. M. Swinbank, J. B. R. Oonk, R. Mittal, B. R. Mcnamara, H. R. Russell, M. N. Bremer, F. Combes, A. C. Fabian, N. P. H. Nesvadba, C. P. O'Dea, S. A. Baum, P. Salomé, G. Tremblay, M. Donahue, Gary J. Ferland, C. L. Sarazin

Physics and Astronomy Faculty Publications

We present multifrequency observations of the radio galaxy Hydra-A (3C218) located in the core of a massive, X-ray luminous galaxy cluster. Integral field unit spectroscopy is used to trace the kinematics of the ionized and warm molecular hydrogen which are consistent with an ∼5 kpc rotating disc. Broad, double-peaked lines of CO(2–1), [C II] 157 μm and [O I] 63 μm are detected. We estimate the mass of the cold gas within the disc to be M_gas = 2.3 ± 0.3 × 10⁹ M_⊙. These observations demonstrate that the complex line profiles found in the cold …

Molecular Opacities For Exoplanets, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

Spectroscopic observations of exoplanets are now possible by transit methods and direct emission. Spectroscopic requirements for exoplanets are reviewed based on existing measurements and model predictions for hot Jupiters and super-Earths. Molecular opacities needed to simulate astronomical observations can be obtained from laboratory measurements, ab initio calculations or a combination of the two approaches. This discussion article focuses mainly on laboratory measurements of hot molecules as needed for exoplanet spectroscopy.

Astronomical Applications Of New Line Lists For Cn, C₂ And Their Isotopologues, P. F. Bernath, Chris Sneden, James S.A. Brooke, Ram S. Ram

Chemistry & Biochemistry Faculty Publications

For cool stellar and substellar objects, atomic lines weaken, and detailed elemental and isotopic abundances are often derived from molecular absorption features. We have embarked on a project to provide molecular line lists by combining experimental observations for line positions with ab initio calculations for line strengths. So far we have results for MgH (A-X and B-X transitions)^ab, C₂ (Swan system)^cd, CP (A-X transition)^f, NH (vibration-rotation bands) and OH (Meinel system)^g. This talk will briefly describe the new line lists for the Swan system (d³Π-a³Π) of C₂ and ¹²C¹³C, and the red …

Ch In Stellar Atmospheres: An Extensive Linelist, T. Masseron, B. Plez, S. Van Eck, R. Colin, I. Daoutidis, M. Godefroid, P.-F. Coheur, P. Bernath, A. Jorissen, N. Christleib

Chemistry & Biochemistry Faculty Publications

The advent of high-resolution spectrographs and detailed stellar atmosphere modelling has strengthened the need for accurate molecular data. Carbon-enhanced metal-poor (CEMP) stars spectra are interesting objects with which to study transitions from the CH molecule. We combine programs for spectral analysis of molecules and stellar-radiative transfer codes to build an extensive CH linelist, including predissociation broadening as well as newly identified levels. We show examples of strong predissociation CH lines in CEMP stars, and we stress the important role played by the CH features in the Bond-Neff feature depressing the spectra of barium stars by as much as 0.2 mag …

A Multiwavelength View On The Dusty Wolf-Rayet Star Wr 48a, Svetozar A. Zhekov, Toma Tomov, Marcin P. Gawronski, Leonid N. Georgiev, Jura Borissova, Radostin Kurtev, Marc Gagne, Marcin Hajduk

Earth & Space Sciences Faculty Publications

No abstract provided.

X-Rays From Magnetic Massive Ob Stars, V. Petit, D. H. Cohen, Y. Naze´, Marc Gagne, R. H.D. Townsend, M. A. Leutenegger, A. Ud-Doula, S. P. Owocki, G. A. Wade

Earth & Space Sciences Faculty Publications

No abstract provided.

Modeling Ionized And Molecular Regions Of The Interstellar Medium Using The Spectral Synthesis Code Cloudy, Gururaj Wagle

Theses and Dissertations--Physics and Astronomy

The focus of this dissertation is to study the star-forming regions of the interstellar medium (ISM), using two very diverse environments: the Polaris Flare, high-galactic latitude, cirrus cloud complex consisting of several starless molecular cores with no nearby hot stars; and the Orion Nebula, which is the closest massive star forming region. The two environments provide a wide range of physical conditions.

It is commonly assumed that the Herschel far-infrared (FIR) fluxes are a good measure of column density, hence, mass of interstellar clouds. We find that the FIR fluxes are insensitive to the column density if A_V ≳ …

Dynamical Models Of Elliptical Galaxies – Ii. M87 And Its Globular Clusters, A. Angello, N. Evans, Aaron Romanowsky, J. Brodie

Faculty Research, Scholarly, and Creative Activity

We study the Globular Cluster (GC) system of the nearby elliptical galaxy M87 using the newly available dataset with accurate kinematics (Strader et al.2011). We find evidence for three distinct sub-populations of GCs in terms of colours, kinematics and radial profiles. We show that a decomposition into three populations (blue, intermediate and red GCs) is statistically preferred to one with two or four populations, and relate them to the stellar profile. We exploit the sub-populations to derive dynamical constraints on the mass and Dark Matter (DM) content of M87 out to ∼100 kpc. We use a class of global mass-estimators …

The Sluggs Survey: New Evidence For A Tidal Interaction Between The Early Type Galaxies Ngc 4365 And Ngc 4342, C. Blom, D. Forbes, C. Foster, Aaron Romanowsky, J. Brodie

Faculty Research, Scholarly, and Creative Activity

We present new imaging and spectral data for globular clusters (GCs) around NGC 4365 and NGC 4342. NGC 4342 is a compact, X-ray luminous S0 galaxy with an unusually massive central black hole. NGC 4365 is another atypical galaxy that dominates the W' group of which NGC 4342 is a member. Using imaging from the MegaCam instrument on the Canada-France-Hawaii Telescope (CFHT) we identify a stream of GCs between the two galaxies and extending beyond NGC 4342. The stream of GCs is spatially coincident with a stream/plume of stars previously identified. We find that the photometric colours of the stream …

Ultra Compact Dwarfs In The Core Of The Perseus Cluster: Ucd Formation Via Tidal Stripping, S. Penny, D. Forbes, J. Strader, C. Usher, J. Brodie, Aaron Romanowsky

Faculty Research, Scholarly, and Creative Activity

We present the results of a Keck/DEIMOS survey of Ultra Compact Dwarfs (UCDs) in the Perseus Cluster core. We confirm cluster membership for 14 UCDs, with radial velocities ~5300 km s−1. Two of these confirmed Perseus UCDs have extremely blue colours (B−R<0.6 mag), reside in star forming filaments surrounding NGC 1275, and have likely formed as massive star clusters in the last ~100 Myr. We also measure a central velocity dispersion of a third, UCD13 (σ0=38±8 km s−1), the most extended UCD in our sample. We determine it to have radius Re=85±1.1 pc, a dynamical mass of (2.3±0.8)×108 M⊙, and a metallicity [Z/H]=−0.52+0.33−0.29 dex. UCD13 and the cluster's central galaxy, NGC 1275, have a projected separation of 30 kpc and a radial velocity difference of ~20 km s−1. Based on its size, red colour, internal velocity dispersion, dynamical mass, metallicity and proximity to NGC 1275, we argue that UCD13 is likely the remnant nucleus of a tidally stripped dE, with this progenitor dE having MB≈−16 mag and mass ∼109 M⊙.

Study Of The Relation Between The Spiral Arm Pitch Angle And The Kinetic Energy Of Random Motions Of The Host Spiral Galaxies, A, I. Al-Baidhany, M. Seigar, P. Treuthardt, A. Sierra, B. Davis, D. Kennefick, J. Kennefick, C. Lacy, Z. A. Toma, W. Jabbar

Journal of the Arkansas Academy of Science

In this work, we report a relation between the kinetic energy of random motions of the corresponding host galaxies and spiral arm pitch angles (Mdynσ2- P), (M*σ2- P) where Mdyn is the bulge dynamical mass, M* is bulge stellar mass, and σ is the velocity dispersion of the host galaxy bulge. We measured the spiral arm pitch angle (P) for a sample of Spitzer/IRAC 3.6-μm images of 54 spiral galaxies, estimated by using a 2D Fast Fourier Transform decomposition technique (2DFFT). We selected a sample of nearly face-on spiral galaxies and used IRAF ellipse to determine the ellipticity and major-axis …

Creation And Application Of Routines For Determining Physical Properties Of Asteroids And Exoplanets From Low Signal-To-Noise Data Sets, Nathaniel Lust

Electronic Theses and Dissertations

Astronomy is a data heavy field driven by observations of remote sources reflecting or emitting light. These signals are transient in nature, which makes it very important to fully utilize every observation. This however is often difficult due to the faintness of these observations, often are only slightly above the level of observational noise. We present new or adapted methodologies for dealing with these low signal-to-noise scenarios, along with practical examples including determining exoplanet physical properties, periodicities in asteroids, and the rotational and orbital properties of the multiple asteroid system 2577 Litva.

Modeling Tidally Driven Coulomb Failure At Strike-Slip Linea On Europa, Marissa Elizabeth Cameron

Open Access Theses & Dissertations

The surface of Europa is crosscut by a dense network of fractures and there are many candidate faults for studying past tectonic activity. To better understand the role of tidal stress sources and implications for faulting on Europa, we investigate the relationship between shear and normal stresses at four fault zones: Agenor Linea, Rhadamanthys Linea, Conamara Chaos (Agave/Asterius Linea), and Astypalaea Linea, offering a unique comparison of geological activity of fractures residing in geographically diverse locations of Europa. Assuming tidal diurnal and non-synchronous rotation (NSR) stresses are the primary mechanisms for strike-slip tectonism, here we investigate the mechanics of Coulomb …

The Structure Of Broad Line Region And The Effects Of Cooling Function In Active Galactic Nuclei, Ye Wang

Theses and Dissertations--Physics and Astronomy

Active Galactic Nuclei (AGNs) are the most mystic objects in the universe. They are usually very far away from our Galaxy, which means that they are ancient objects. They are also luminous and have unique features in their spectra. Studying AGNs helps understanding the early universe and the evolution of galaxies. This Dissertation aims to research the structure of AGNs and the cooling function in the AGNs environment.

I first investigate what optical/ultraviolet spectroscopic features would be produced by Broad-line Region (BLR) clouds crossing our line of sight to the accretion disk, the source of the optical/UV continuum. This research, …

Reevaluation Of The Aapm Tg-43 Brachytherapy Dosimetry Parameters For An 125I Seed, And The Influence Of Eye Plaque Design On Dose Distributions And Dose-Volume Histograms, Prakash Aryal

Theses and Dissertations--Physics and Astronomy

The TG-43 dosimetry parameters of the Advantage^{TM 125}I model IAI-125A brachytherapy seed were studied. An investigation using modern MCNP radiation transport code with updated cross-section libraries was performed. Twelve different simulation conditions were studied for a single seed by varying the coating thickness, mass density, photon energy spectrum and cross-section library. The dose rate was found to be 6.3% lower at 1 cm in comparison to published results. New TG-43 dosimetry parameters are proposed.

The dose distribution for a brachytherapy eye plaque, model EP917, was investigated, including the effects of collimation from high-Z slots. Dose distributions for …

A New Set Of Spectroscopic Metallicity Calibrations For Rr Lyrae Variable Stars, Eckhart Spalding

Theses and Dissertations--Physics and Astronomy

RR Lyrae stars are old, iron-poor, Helium-burning variable stars. RR Lyraes are extremely useful for tracing phase-space structures and metallicities within the galaxy because they are easy to identify, have consistent luminosities, and are found in large numbers in the galactic disk, bulge, and halo. Here we present a new set of spectroscopic metallicity calibrations that use the equivalent widths of the Ca II K, Hγ, and Hδ lines to calculate metallicity values. Applied to spectroscopic survey data, these calibrations will help shed light on the evolution of the Milky Way and other galaxies.