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2007

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Articles 151 - 180 of 202

Full-Text Articles in Astrophysics and Astronomy

He I Emission In The Orion Nebula And Implications For Primordial Helium Abundance, R. L. Porter, Gary J. Ferland, K. B. Macadam Mar 2007

He I Emission In The Orion Nebula And Implications For Primordial Helium Abundance, R. L. Porter, Gary J. Ferland, K. B. Macadam

Physics and Astronomy Faculty Publications

We apply a recently developed theoretical model of helium emission to observations of both the Orion Nebula and a sample of extragalactic H II regions. In the Orion analysis, we eliminate some weak and blended lines and compare theory and observation for our reduced line list. With our best theoretical model we find an average difference between theoretical and observed intensities (Ipred/Iobs-1)=6.5%. We argue that both the red and blue ends of the spectrum may have been inadequately corrected for reddening. For the 22 highest quality lines, with 3499 Å≤λ≤6678 Å, our best model …

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Abundance Analysis Of The Extremely Fast Onemg Novae V838 Herculis And V4160 Sagittarii, G J. Schwarz, S N. Shore, S Starrfield, K M. Vanlandingham Mar 2007

Abundance Analysis Of The Extremely Fast Onemg Novae V838 Herculis And V4160 Sagittarii, G J. Schwarz, S N. Shore, S Starrfield, K M. Vanlandingham

Earth & Space Sciences Faculty Publications

V838 Her and V4160 Sgr were two of the fastest classical novae ever observed, exhibiting light curve declines of 2 mag in less than 2 days. Both novae also showed strong neon emission lines, indicative of an outburst occurring on an oxygen-neon-magnesium white dwarf. Being the brighter of the two, V838 Her has an extensive set of X-ray to radio observations obtained during its first year after outburst. V4160 Sgr has a more modest set of ultraviolet and optical spectra, which show it to be similar to V838 Her, not just in its light curve evolution but also in its …

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Induced Nested Galactic Bars Inside Assembling Dark Matter Halos, Clayton Heller, Isaac Shlosman, Evangelie Athanassoula Mar 2007

Induced Nested Galactic Bars Inside Assembling Dark Matter Halos, Clayton Heller, Isaac Shlosman, Evangelie Athanassoula

Physics & Astronomy: Faculty Publications

We investigate the formation and evolution of nested bar systems in disk galaxies in a cosmological setting by following the development of an isolated dark matter (DM) and baryon density perturbation. The disks form within the assembling triaxial DM halos, and the feedback from the stellar evolution is accounted for in terms of supernovae and OB stellar winds. Focusing on a representative model, we show the formation of an oval disk and of a first generation of nested bars with characteristic subkiloparsec sizes and a few kiloparsec sizes. The system evolves through successive dynamical couplings and decouplings, forcing the gas …

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Bounds And Conditions: A Kolob In Our Solar System?, David D. Allred Mar 2007

Bounds And Conditions: A Kolob In Our Solar System?, David D. Allred

Faculty Publications

In 2003, Dialogue ran adjacent essays by two scientists, David Tolman and David Allred. The two Davids had been students together at Princeton, attending the same student ward. Decades after Princeton, Tolman had left Mormonism and Allred had stayed. Their essays are a fascinating juxtaposition. In the course of his piece, David Allred ventured for a few paragraphs into a discussion of the planet Jupiter and its role as a governor and protector in our solar system—a type of Kolob. Although the other author dismissed the topic as “fanciful physics,” my own interest was piqued. I asked Dr. Allred, who …

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Photometry And Spectroscopy Of 11 Γ Doradus Stars, Gregory W. Henry, Francis C. Fekel, Stephen M. Henry Feb 2007

Photometry And Spectroscopy Of 11 Γ Doradus Stars, Gregory W. Henry, Francis C. Fekel, Stephen M. Henry

Information Systems and Engineering Management Research Publications

We have used precise photometric and high-dispersion spectroscopic observations to study 11 γ Doradus stars, 10 of them newly confirmed. Only five of these 11 γ Doradus stars appear to be single; two are primaries of double-lined spectroscopic binaries, one is the secondary of a double-lined binary, two are primaries of visual binaries and, in the case of the double-lined binary (HD 86371), either or both components could be a pulsating γ Doradus star. We have determined a preliminary orbital period of 5.32 days for the double-lined binary HD 41547. Several of the stars show spectroscopic line-profile and low-amplitude radial …

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The Effect Of Cluster Environment On Galaxy Evolution In The Pegasus I Cluster, Lorenza Levy, James A. Rose, Jacqueline H. Van Gorkom, Brian Chaboyer Feb 2007

The Effect Of Cluster Environment On Galaxy Evolution In The Pegasus I Cluster, Lorenza Levy, James A. Rose, Jacqueline H. Van Gorkom, Brian Chaboyer

Dartmouth Scholarship

We present neutral hydrogen observations of 54 galaxies in the Pegasus Cluster. The observations include single-dish H I measurements, obtained with the Arecibo telescope for all 54 galaxies in the sample, as well as H I images obtained with the Very Large Array (VLA) for 10 of these. The Arecibo profiles reveal an overall H I deficiency in the cluster, with similar to 40% of the galaxies in the core of the cluster showing modest deficiencies of typically a factor of 2-3. The HI morphology of so me galaxies shows that the HI disk is smaller than the optical disk …

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The Metallicity Distribution Of Intracluster Stars In Virgo, Benjamin F. Willaims, Ted Von Hippel, Et Al. Feb 2007

The Metallicity Distribution Of Intracluster Stars In Virgo, Benjamin F. Willaims, Ted Von Hippel, Et Al.

Publications

We have used the Hubble Space Telescope's Advanced Camera for Surveys (ACS) to detect and measure ~5300 stars in a single intracluster field in the Virgo Cluster. By performing F606W and F814W photometry on these stars, we have determined their metallicity distribution function and constrained the types of stars present in this portion of Virgo's intracluster space. Based on the small number of stars detected that were brighter than the red giant branch (RGB) tip, we suggest that in this region, Virgo's intracluster stars are mostly old (10 Gyr). Through analysis of the RGB stars themselves, we determine that …

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The Resolved Stellar Populations Of A Dwarf Spheroidal Galaxy In The Virgo Cluster, Patrick R. Durell, Ted Von Hippel, Et Al. Feb 2007

The Resolved Stellar Populations Of A Dwarf Spheroidal Galaxy In The Virgo Cluster, Patrick R. Durell, Ted Von Hippel, Et Al.

Publications

We report on the discovery of a faint (MV ~ -10.6 ± 0.2) dwarf spheroidal galaxy on deep F606W and F814W Hubble Space Telescope images of a Virgo intracluster field. The galaxy is easily resolved in our images, as our color magnitude diagram (CMD) extends 1 magnitude beyond the tip of the red giant branch (RGB). Thus, it is the deepest CMD for a small dwarf galaxy inside a cluster environment. Using the colors of the RGB stars, we derive a metal abundance for the dwarf of [M/H] = -2.3 ± 0.3 and show that the metallicity dispersion …

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Photospheric And Chromospheric Active Regions In Four Young Solar-Type Stars, Katia Biazzo, Antonio Frasca, Gregory W. Henry, S. Catalano, E. Marilli Feb 2007

Photospheric And Chromospheric Active Regions In Four Young Solar-Type Stars, Katia Biazzo, Antonio Frasca, Gregory W. Henry, S. Catalano, E. Marilli

Information Systems and Engineering Management Research Publications

We present a photometric and spectroscopic study of four G-K dwarfs, namely HD 166, epsilon Eri, χ1 Ori, and κ1 Cet. In three cases, we find a clear spatial association between photospheric and chromospheric active regions. For χ1 Ori we do not find appreciable variations of photospheric temperature or chromospheric Hα emission. We applied a spot/plage model to the observed rotational modulation of temperature and flux to derive spot/plage parameters and to reconstruct a rough "three-dimensional" map of the outer atmosphere of κ1 Cet, HD 166, and epsilon Eri.

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The Wind‐Ism Interaction Of Α Tauri, Brian E. Wood, Graham M. Harper, Hans-Reinhard Muller, Jacob Heerikhuisen, Gary P. Zank Feb 2007

The Wind‐Ism Interaction Of Α Tauri, Brian E. Wood, Graham M. Harper, Hans-Reinhard Muller, Jacob Heerikhuisen, Gary P. Zank

Dartmouth Scholarship

Ultraviolet spectra of α Tau (K5 III) obtained by the Hubble Space Telescope (HST) show many emission lines affected by broad absorption from the strong wind of this red giant star. For the Mg II h and k lines there is also a narrow absorption feature in the midst of the wind absorption that has been interpreted as being from α Tau's wind-interstellar medium (ISM) interaction region (i.e., its "astrosphere"). We try to reproduce this absorption using hydrodynamic models of the α Tau astrosphere, which show that stellar wind material heated, compressed, and decelerated at the wind's termination …

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The Distribution Of Silicate Strength In Spitzer Spectra Of Agns And Ulirgs, Lei Hao, D. W. Weedman, H. Spoon, J. A. Marshall, N. A. Levenson, Moshe Elitzur, J. R. Houck Feb 2007

The Distribution Of Silicate Strength In Spitzer Spectra Of Agns And Ulirgs, Lei Hao, D. W. Weedman, H. Spoon, J. A. Marshall, N. A. Levenson, Moshe Elitzur, J. R. Houck

Physics and Astronomy Faculty Publications

A sample of 196 AGNs and ULIRGs observed by the Infrared Spectrograph (IRS) on Spitzer is analyzed to study the distribution of the strength of the 9.7 μm silicate feature. Average spectra are derived for quasars, Seyfert 1 and Seyfert 2 AGNs, and ULIRGs. We find that quasars are characterized by silicate features in emission and Seyfert 1s equally by emission or weak absorption. Seyfert 2s are dominated by weak silicate absorption, and ULIRGs are characterized by strong silicate absorption (mean apparent optical depth about 1.5). Luminosity distributions show that luminosities at rest frame 5.5 μm are similar …

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The Structure Of The Homunculus. Ii. Modeling The Physical Conditions In Η Carinae's Molecular Shell, Nathan Smith, Gary J. Ferland Feb 2007

The Structure Of The Homunculus. Ii. Modeling The Physical Conditions In Η Carinae's Molecular Shell, Nathan Smith, Gary J. Ferland

Physics and Astronomy Faculty Publications

We present models that reproduce the observed double-shell structure of the Homunculus Nebula around η Carinae, including the stratification of infrared H2 and [Fe II] emission seen in data obtained with the Phoenix spectrograph on Gemini South, as well as the corresponding stratified grain temperature seen in thermal-infrared data. Tuning the model to match the observed shell thickness allows us to determine the threshold density that permits survival of H2. An average density of nH~=(0.5-1)×107 cm-3 in the outer zone is required to allow H2 to exist at all latitudes in the …

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The Abundance Of Carbon Dioxide Ice In The Quiescent Intracloud Medium, D. Whittet, S. Shenoy, E. Bergin, J. Chiar, P. Gerakines, E. Gibb, G. Melnick, D. Neufeld Jan 2007

The Abundance Of Carbon Dioxide Ice In The Quiescent Intracloud Medium, D. Whittet, S. Shenoy, E. Bergin, J. Chiar, P. Gerakines, E. Gibb, G. Melnick, D. Neufeld

Physics Faculty Works

We present new observations with the Infrared Spectrograph on board the Spitzer Space Telescope of the solid-CO2 absorption feature near 15 μm in the spectra of eight field stars behind the Taurus complex of dark clouds. Solid CO2 is detected in six lines of sight. New results are combined with previous data to investigate the correlation of CO2 column density with those of other major ice constituents (H2O and CO) and with extinction. CO2 is shown to display a "threshold extinction" effect, i.e., a minimum extinction (A0 = 4.3 ± 1.0 mag) required for detection, behavior similar to that previously …

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Very High Energy Observations Of Gamma-Ray Burst Locations With The Whipple Telescope, P. T. Reynolds, Et. Al. Jan 2007

Very High Energy Observations Of Gamma-Ray Burst Locations With The Whipple Telescope, P. T. Reynolds, Et. Al.

Physical Sciences Publications

Gamma-ray burst (GRB) observations at very high energies (VHE; E > 100 GeV) can impose tight constraints on some GRB emission models. Many GRB afterglow models predict a VHE component similar to that seen in blazars and plerions, in which the GRB spectral energy distribution has a double-peaked shape extending into the VHE regime. VHE emission coincident with delayed X-ray flare emission has also been predicted. GRB follow-up observations have had high priority in the observing program at the Whipple 10 m gamma-ray telescope, and GRBs will continue to be high-priority targets as the next-generation observatory, VERITAS, comes online. Upper limits …

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Mosaicking With Cosmic Microwave Background Interferometers, Emory F. Bunn, Martin White Jan 2007

Mosaicking With Cosmic Microwave Background Interferometers, Emory F. Bunn, Martin White

Physics Faculty Publications

Measurements of cosmic microwave background (CMB) anisotropies by interferometers offer several advantages over single-dish observations. The formalism for analyzing interferometer CMB data is well developed in the flat-sky approximation, which is valid for small fields of view. As the area of sky is increased to obtain finer spectral resolution, this approximation needs to be relaxed. We extend the formalism for CMB interferometry, including both temperature and polarization, to mosaics of observations covering arbitrarily large areas of the sky, with each individual pointing lying within the flat-sky approximation. We present a method for computing the correlation between visibilities with arbitrary pointing …

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A Dyad Theory Of Hydrodynamics And Electrodynamics, Preston Jones Jan 2007

A Dyad Theory Of Hydrodynamics And Electrodynamics, Preston Jones

Publications

The dyadic calculus is developed in a form suitable for the description of physical relations in curved space. The 4-space equations of hydrodynamics and electrodynamics are constructed using this dyadic calculus. As a demonstration of the relationship between gravity and electrodynamics a time varying metric is shown to generate electromagnetic radiation.

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Virgo’S Intracluster Globular Clusters As Seen By The Advanced Camera For Surveys, Benjamin F. Williams, Robin Ciardullo, Ted Von Hippel, Et Al. Jan 2007

Virgo’S Intracluster Globular Clusters As Seen By The Advanced Camera For Surveys, Benjamin F. Williams, Robin Ciardullo, Ted Von Hippel, Et Al.

Publications

We report the discovery of four candidate intracluster globular clusters (IGCs) in a single deepHST ACS field of the Virgo Cluster. We show that each cluster is roughly spherical, has a magnitude near the peak of the Virgo globular cluster luminosity function, has a radial profile that is best fitted by a King model, and is surrounded by an excess of point sources that have the colors and magnitudes of cluster red giant stars. Despite the fact that two of our IGC candidates have integrated colors redder than the mean of the M87 globular cluster system, we propose that …

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Strain-Based Electrical Properties Of Systems Of Carbon Nanotubes Embedded In Parylene, David D. Allred, Jon Brame, Johnathan Goodsell, Stephanie Getty Jan 2007

Strain-Based Electrical Properties Of Systems Of Carbon Nanotubes Embedded In Parylene, David D. Allred, Jon Brame, Johnathan Goodsell, Stephanie Getty

Faculty Publications

We have fabricated flexible electronic devices to test the strain-based change in resistance of a network of single-walled carbon nanotubes (SWCNTs) for use in microscale, high resolution magnetometry. To do this, we first develop a simple, reliable method to obtain catalyst nanoparticles for carbon nanotube growth through indirect, thin-film evaporation. Next we fabricate a two-terminal SWCNT device on a rigid substrate. We then transfer the device, intact, to a flexible substrate for strain testing. Herein, we report progress in growth and measurement techniques.

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Purification By Fire : 2 Peter 3 And The Stoic Cosmos, Peter G. Speiser Jan 2007

Purification By Fire : 2 Peter 3 And The Stoic Cosmos, Peter G. Speiser

Master of Arts Theses

No abstract provided.

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Reissner–Nordstrom¨ Expansion, Emil Prodanov, Rossen Ivanov, V.G. Gueorguiev Jan 2007

Reissner–Nordstrom¨ Expansion, Emil Prodanov, Rossen Ivanov, V.G. Gueorguiev

Conference papers

We propose a classical mechanism for the cosmic expansion during the radiation-dominated era, assuming the Universe as a two-component gas. The first component is the ultra-relativistic “standard” fraction described by an equation of state of an ideal quantum gas of massless particles. The second component consist of superheavy charged particles and their interaction with the “standard” fraction drives the expansion. This interaction is described by the Reissner–Nordstr¨om metric purely geometrically — the superheavy charged particles are modeled as zero-dimensional naked singularities which exhibit gravitational repulsion. The radius of a repulsive sphere, surrounding a naked singularity of charge Q, is inversely …

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Algorithm Refinement For Fluctuating Hydrodynamics, Alejandro Garcia, S. Williams, J. B. Bell Jan 2007

Algorithm Refinement For Fluctuating Hydrodynamics, Alejandro Garcia, S. Williams, J. B. Bell

Faculty Publications

This paper introduces an adaptive mesh and algorithm refinement method for fluctuating hydrodynamics. This particle-continuum hybrid simulates the dynamics of a compressible fluid with thermal fluctuations. The particle algorithm is direct simulation Monte Carlo (DSMC), a molecular-level scheme based on the Boltzmann equation. The continuum algorithm is based on the Landau–Lifshitz Navier–Stokes (LLNS) equations, which incorporate thermal fluctuations into macroscopic hydrodynamics by using stochastic fluxes. It uses a recently developed solver for the LLNS equations based on third-order Runge–Kutta. We present numerical tests of systems in and out of equilibrium, including time-dependent systems, and demonstrate dynamic adaptive refinement by the …

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Infrared Spectroscopy Of Symbiotic Stars. V. First Orbits For Three S-Type Systems: Henize 2-173, Cl Scorpii, And As 270, Francis C. Fekel, Kenneth H. Hinkle, Richard R. Joyce, Peter R. Wood, Thomas Lebzelter Jan 2007

Infrared Spectroscopy Of Symbiotic Stars. V. First Orbits For Three S-Type Systems: Henize 2-173, Cl Scorpii, And As 270, Francis C. Fekel, Kenneth H. Hinkle, Richard R. Joyce, Peter R. Wood, Thomas Lebzelter

Information Systems and Engineering Management Research Publications

Infrared radial velocities have been used to compute first orbits of the M giants in three southern S-type symbiotic systems. Of the three, Hen 2-173 has the longest orbital period, 911 days, and also has a noncircular orbit with an eccentricity of 0.21. The large value of its mass function suggests that Hen 2-173 may be an eclipsing system. For CL Sco our spectroscopic orbital period of 626 days is essentially identical to the previously determined light variability period of 625 days, and we have adopted the latter. AS 270 has an orbital period of similar length, 671 days, and …

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The Record-Breaking Rotational Braking Of The He Strong Cp Star Hd 37776, Zdeněk Mikulášek, Jiří Krtička, Juraj Zverko, Gregory W. Henry, Jan Janik, Iosif I. Romanyuk, Jozef Ziznovsky, Hrvoje Božić, Miloslav Zejda, Thomas Graf, Martin Netolický Jan 2007

The Record-Breaking Rotational Braking Of The He Strong Cp Star Hd 37776, Zdeněk Mikulášek, Jiří Krtička, Juraj Zverko, Gregory W. Henry, Jan Janik, Iosif I. Romanyuk, Jozef Ziznovsky, Hrvoje Božić, Miloslav Zejda, Thomas Graf, Martin Netolický

Information Systems and Engineering Management Research Publications

We study the long-term light and spectral variations in the He-strong magnetic chemically peculiar star HD 37776 (V901 Ori) to search for changes of its 1.5387 d period in 1976-2007. We analyze all published photometric observations and spectrophotometry in the HeI 4026 A line. The data were supplmented with 506 new (U)VB observations obtained during the last 2 observing seasons, 66 estimates of HeI equivalent widths on 23 CFHT spectrograms and 35 of the 6-m Zeeman spectrograms. All the 1895 particular observations heve been processed simultaneously. We confirm the previously suspected increase of the period in HD 37776 which is …

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Maya Eclipses: Modern Data, The Triple Tritos And The Double Tzolkin, William Earl Beck Jan 2007

Maya Eclipses: Modern Data, The Triple Tritos And The Double Tzolkin, William Earl Beck

Electronic Theses and Dissertations

The Eclipse Table, on pages 51-58, of the Dresden Codex has long fascinated Maya scholars. Researchers use the mean-value method of 173.3 days to determine nodal passage that is the place where eclipses can occur. These studies rely on Oppolzer's Eclipse Canon and Schram's Moon Phase Tables to verify eclipse occurrences. The newer canons of Jean Meeus and Bao-Lin Liu use decimal accuracy. What would be the effect of modern astronomical data on the previous studies and the Maya Eclipse Table? The study utilizes a general view of eclipses that includes eclipses not visible to the Maya. Lunar eclipses are …

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Scientists Are Urged To Look For Extraterrestrial Life Forms, Aldemaro Romero Jr., David Gilmore Jan 2007

Scientists Are Urged To Look For Extraterrestrial Life Forms, Aldemaro Romero Jr., David Gilmore

Publications and Research

No abstract provided.

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Thermal Properties Of Cubic Kta 1 X Nb X O 3 Crystals, X. P. Wang, J. Y. Wang, H. J. Zhang, Y. G. Yu, J. Wu, W. L. Gao, Robert I. Boughton Jan 2007

Thermal Properties Of Cubic Kta 1 X Nb X O 3 Crystals, X. P. Wang, J. Y. Wang, H. J. Zhang, Y. G. Yu, J. Wu, W. L. Gao, Robert I. Boughton

Physics and Astronomy Faculty Publications

Cubic potassium tantalite niobate KTa1−xNbxO3 KTN crystals of large size, good quality, and varying Nb concentration have been grown by the Czochralski method and their thermal properties have been systematically studied. The melting point, molar enthalpy of fusion, and molar entropy of fusion of the crystals were determined to be: 1536.9 K, 12 068.521 J mol−1, and 7.85 J K−1 mol−1 for KTa0.67Nb0.33O3; and 1520.61 K, 15 352.511 J mol−1, and 10.098 J K−1 mol−1 for KTa0.67Nb0.33O3, respectively. Based on the data, the Jackson factor was calculated to be 0.994f and 1.214f for KTa0.67Nb0.33O3 and KTa0.63Nb0.37O3, respectively. The thermal expansion …

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The Star Pile In Abell 545, R. Salinas, T. Richtler, M. J. West, Aaron J. Romanowsky, Y. Schuberth Jan 2007

The Star Pile In Abell 545, R. Salinas, T. Richtler, M. J. West, Aaron J. Romanowsky, Y. Schuberth

Faculty Publications

Context.Struble (1988, ApJ, 330, L25) found what appeared to be a cD halo without cD galaxy in the center of the galaxy cluster Abell 545. This remarkable feature has been passed almost unnoticed for nearly twenty years. Aims.Our goal is to review Struble's claim by providing a first (preliminary) photometric and spectroscopic analysis of this "star pile". Methods.Based on archival VLT-images and long-slit spectra obtained with Gemini-GMOS, we describe the photometric structure and measure the redshift of the star pile and of the central galaxy. Results.The star pile is indeed associated with Abell 545. Its velocity is higher by about …

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Numerical Methods For The Stochastic Landau-Lifshitz Navier-Stokes Equations, Alejandro Garcia, J. B. Bell, S. Williams Jan 2007

Numerical Methods For The Stochastic Landau-Lifshitz Navier-Stokes Equations, Alejandro Garcia, J. B. Bell, S. Williams

Faculty Publications

The Landau-Lifshitz Navier-Stokes (LLNS) equations incorporate thermal fluctuations into macroscopic hydrodynamics by using stochastic fluxes. This paper examines explicit Eulerian discretizations of the full LLNS equations. Several computational fluid dynamics approaches are considered (including MacCormack’s two-step Lax-Wendroff scheme and the piecewise parabolic method) and are found to give good results for the variance of momentum fluctuations. However, neither of these schemes accurately reproduces the fluctuations in energy or density. We introduce a conservative centered scheme with a third-order Runge-Kutta temporal integrator that does accurately produce fluctuations in density, energy, and momentum. A variety of numerical tests, including the random walk …

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The Pn.S Elliptical Galaxy Survey: Data Reduction, Planetary Nebula Catalog, And Basic Dynamics For Ngc 3379, N. G. Douglas, N. R. Napolitano, Aaron J. Romanowsky, L. Coccato, K. Kuijken, M. R. Merrifield, M. Arnaboldi, O. Gerhard, K. C. Freeman, H. R. Merrett, E. Noordermeer, M. Capaccioli Jan 2007

The Pn.S Elliptical Galaxy Survey: Data Reduction, Planetary Nebula Catalog, And Basic Dynamics For Ngc 3379, N. G. Douglas, N. R. Napolitano, Aaron J. Romanowsky, L. Coccato, K. Kuijken, M. R. Merrifield, M. Arnaboldi, O. Gerhard, K. C. Freeman, H. R. Merrett, E. Noordermeer, M. Capaccioli

Faculty Publications

We present results from Planetary Nebula Spectrograph (PN.S) observations of the elliptical galaxy NGC 3379 and a description of the data reduction pipeline. We detected 214 planetary nebulae, of which 191 are ascribed to NGC 3379 and 23 to the companion galaxy NGC 3384. Comparison with data from the literature shows that the PN.S velocities have an internal error of lesssim20 km s-1 and a possible offset of similar magnitude. We present the results of kinematic modeling and show that the PN kinematics is consistent with absorption-line data in the region where they overlap. The resulting combined kinematic data set, …

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Bianchi Identities And Weak Gravitational Lensing, Brian Keith Jan 2007

Bianchi Identities And Weak Gravitational Lensing, Brian Keith

Undergraduate Review

No abstract provided.

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