Astrophysics and Astronomy Commons^™

Application Of Asymptotic Expansions For Maximum Likelihood Estimators' Errors To Gravitational Waves From Inspiraling Binary Systems: The Network Case, Salvatore Vitale, Michele Zanolin

Michele Zanolin

Environmental Research With Undergraduates In East Asia: Collaborations In China And Japan, Gary A. Morris, Jon Schoer

Gary A. Morris

China: From 2007-2008 as part of a collaborative research project funded by the ASIANetwork, VU and the VLACD, 5 VU students (2 chemistry, 1 biology, 1 environmental science, and 1 civil engineering) spent 3 weeks in Zhejiang province, China and 7 additional weeks in northwest Indiana comparing and contrasting water quality issues and attitudes in the two regions. While in China, the students interacted with one another and graduate students, faculty, and staff from Zhejiang University and Zhejiang A &F University, and with multiple local & regional officials and residents to collect water quality data and opinions about key water …

Kepler And Ground-Based Transits Of The Exo-Neptune Hat-P-11b, Drake Deming, Pedro V. Sada, Brian Jackson, Steven W. Peterson, Eric Agol, Heather A. Knutson, Donald E. Jennings, Flynn Haase, Kevin Bays

Brian Jackson

We analyze 26 archival Kepler transits of the exo-Neptune HAT-P-11b, supplemented by ground-based transits observed in the blue (B band) and near-IR (J band). Both the planet and host star are smaller than previously believed; our analysis yields Rp = 4.31 R⊕ ± 0.06 R ⊕ and Rs = 0.683 R☉ ± 0.009 R☉, both about 3σ smaller than the discovery values. Our ground-based transit data at wavelengths bracketing the Kepler bandpass serve to check the wavelength dependence of stellar limb darkening, and the J-band transit provides a precise and independent constraint on the transit duration. Both the limb darkening …

Holographic Renormalization Of Asymptotically Lifshitz Spacetimes, Robert Mcnees, Robert Mann

Robert A McNees IV

A variational formulation is given for a theory of gravity coupled to a massive vector in four dimensions, with Asymptotically Lifshitz boundary conditions on the fields. For theories with critical exponent z = 2 we obtain a well-defined variational principle by explicitly constructing two actions with local boundary counterterms. As part of our analysis we obtain solutions of these theories on a neighborhood of spatial infinity, study the asymptotic symmetries, and consider different definitions of the boundary stress tensor and associated charges. A constraint on the boundary data for the fields figures prominently in one of our formulations, and in …

Radial Velocities Of Galactic O-Type Stars. I. Short-Term Constant Velocity Stars, S. J. Williams, D. R. Gies, Todd Hillwig, M. V. Mcswain, W. Huang

Todd Hillwig

Early Magnetic B-Type Stars: X-Ray Emission And Wind Properties., L. M. Oskinova, H. Todt, R. Ignace, J. C. Brown, J. P. Cassinelli, W.-R. Hamann

Richard Ignace

We present a comprehensive study of X-ray emission by, and wind properties of, massive magnetic early B-type stars. Dedicated XMM–Newton observations were obtained for three early-type B-type stars, ξ¹ CMa, V2052 Oph and ζ Cas, with recently discovered magnetic fields. We report the first detection of X-ray emission from V2052 Oph and ζ Cas. The latter is one the softest X-ray sources among the early-type stars, while the former is one of the X-ray faintest. The observations show that the X-ray spectra of our programme stars are quite soft with the bulk of X-ray emitting material having a temperature …

H I Asymmetries In The Isolated Galaxy Cig 292, Antonio Portas, Tom C. Scott, Elias Brinks, Albert Bosma, Lourdes Verdes-Montenegro, Volker Heesen, Daniel Espada, Simon Verley, Jack Sulentic, Chandreyee Sengupta, E Athanassoula, Min S. Yun

Min S. Yun

We present Expanded Very Large Array (EVLA) D-array observations of the 21 cm line of neutral hydrogen (H I) of CIG 292, an isolated SA(s)b galaxy at a distance of ~24.3 Mpc. From previous H I single dish observations the galaxy was known to have a mildly asymmetric H I profile (A flux = 1.23 ± 0.3). Our EVLA observations show there is ~12% more H I projected south of the optical center (approaching velocities) than in the north (receding velocities), despite the H I extending ~16% further to the north than the south. The H I projected within the …

Vuv Absorption Cross Section Of Benzene, Relevance For Titan’S Atmosphere, F-J. Capalbo, Y. Bénilan, N. Fray, M. Schwell, Et. Es-Sebbar, N. Champion, T. Koskinen, R. Yelle

Dr. Et-touhami Es-sebbar

Saturn's largest satellite, Titan, is the only one in the Solar System known to have a thick N2/CH4, planet like atmosphere. The dissociation of these principal components and the recombination of the products make this atmosphere to be rich in organic compounds of high interest for astrobiology. Solar and stellar occultations observed by the Ultraviolet Imaging Spectrograph (UVIS) on board the Cassini spacecraft can be used to characterize the composition of Titan’s upper atmosphere (400 – 1400 km). The results depend strongly on the knowledge of the molecular absorption cross sections of the atmospheric constituents (Ferradaz et al. 2009). This …

The M81 Group Dwarf Irregular Galaxy Ddo165. Ii. Connecting Recent Star Formation With Ism Structures And Kinematics, John M. Cannon, Hans P. Most, Evan D. Skillman, Daniel R. Weisz, David Cook, Andrew E. Dolphin, Robert C. Kennicutt, Jr., Janice Lee, Anil Seth, Fabian Walter, Steven R. Warren

John Cannon

No abstract provided.

Temporal And Spatial Aspects Of Gas Release During The 2010 Apparition Of Comet 103p/Hartley 2, M. J. Mumma, B. P. Bonev, G. L. Villanueva, L. Paganini, M. A. Disanti, E. L. Gibb, J. V. Keane, K. J. Meech, G. A. Blake, R. S. Ellis, M. Lippi, H. Boehnhardt, K. Magee-Sauer

Erika Gibb

Relating Bs Mixing And Bs → Μ+Μ− With New Physics, Eugene Golowich, Joanne Hewett, Sandip Pakvasa, Alexey A. Petrov, Gagik K. Yeghiyan

Eugene Golowich

We perform a study of the Standard Model (SM) fit to the mixing quantities ∆MB_s, and ∆TB_s/∆MB_s in order to bound contributions of New Physics to B_s mixing. We then use this to explore the branching fraction of B_s → μ+μ− in certain models of New Physics (NP). In most cases, this constrains NP amplitudes for B_s → μ+μ− to lie below the SM component.

Relativistic Gravitational Potential Energy And General Free Fall: A Fundamental Topic In Physics, Jorge A. Franco

Jorge A Franco

In this paper, we derived expressions of the relativistic potential energy for radial, circular and general curvilinear motion of a mass under the influence of a gravitational field, and the equivalence relationship between velocity and radius in each case. Also it was obtained the influence of altitude on time, mass, length and other physical magnitudes for circular and general curvilinear motion, and for the static case or radial.

Relativistic Analysis Of Doppler Effect And Aberration Based On Vectorial Lorentz Transformations, Jorge A. Franco

Jorge A Franco

In this paper, we derived more general and correct expressions for the Relativistic Doppler and Aberration effect.

Time-Dependent Behavior Of Linear Polarization In Unresolved Photospheres, With Applications For The Hanle Effect., R. Ignace, K. T. Hole, J. P. Cassinelli, G. D. Henson

Richard Ignace

Aims: This paper extends previous studies in modeling time varying linear polarization due to axisymmetric magnetic fields in rotating stars. We use the Hanle effect to predict variations in net line polarization, and use geometric arguments to generalize these results to linear polarization due to other mechanisms. Methods: Building on the work of Lopez Ariste et al., we use simple analytic models of rotating stars that are symmetric except for an axisymmetric magnetic field to predict the polarization lightcurve due to the Hanle effect. We highlight the effects for the variable line polarization as a function of viewing inclination and …

A Study Of Massive And Evolved Galaxies At High Redshift, H. Nayyeri, B. Mobasher, H. C. Ferguson, S. De Barros, T. Wiklind, T. Dahlen, M. Dickinson, Mauro Giavalisco, A. Fontana, M.L.N. Ashby, G. Barro, Y. Guo, N.P. Hathi, S. Kassin, A. Koekemoer, S. Willner

Mauro Giavalisco

We use data taken as part of HST/WFC3 observations of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) to identify massive and evolved galaxies at 3 < z < 4:5. This is performed using the strength of the Balmer break feature at rest-frame 3648_A, which is a diagnostic of the age of the stellar population in galaxies. Using WFC3 H-band selected catalog for the CANDELS GOODS-S field and deep multi-waveband photometry from optical (HST) to mid- infrared (Spitzer) wavelengths, we identify a population of old and evolved post-starburst galaxies based on the strength of their Balmer breaks (Balmer Break Galaxies- BBGs). The galaxies are also selected to be bright in rest-frame near-IR wavelengths and hence, massive. We identify a total of 16 BBGs. Fitting the spectral energy distribution (SED) of the BBGs show that the candidate galaxies have average estimated ages of ~800 Myr and average stellar masses of _ 5_1010M_, consistent with being old and massive systems. Two of our BBG candidates are also identified by the criteria that is sensitive to star forming galaxies (LBG selection). We find a number density of _ 3:2 _ 10^-5 Mpc^-3 for the BBGs corresponding to a mass density of ~ 2:0x106M. / Mpc3 in the redshift range covering the survey. Given the old age and the passive evolution, it is argued that some of these objects formed the bulk of their mass only a few hundred million years after the Big Bang.

The Evolution Of Stellar Structures In Dwarf Galaxies, N. Bastian, D. R. Weisz, E. D. Skillman, K.B. W. Mcquinn, A. E. Dolphin, R. A. Gutermuth, John M. Cannon, B. Ercolano, M. Gieles, R. C. Kennicutt, F. Walter

John Cannon

No abstract provided.

Characterization Of Continuous Vacuum Ultraviolet Lamps-Implication On The Study Of Methane Photolysis At Lyman Alpha (121.6 Nm), M-C. Gazeau, Y. Benilan, Et. Es-Sebbar, A. Jolly, E. Arzoumanian, N. Fray, H. Cottin

Dr. Et-touhami Es-sebbar

Low-temperature hydrogen plasmas are widely used as continuous vacuum ultraviolet irradiation sources in photochemical studies and, in particular, in laboratory simulations of planetary atmospheres. One of the most challenging objectives of such experiments is to retrieve accurate quantitative laboratory data allowing a reliable comparison with theoretical and/or observational ones. This task can only be achieved when the irradiation source delivers a well characterised radiation in terms of flux and wavelength dependency. As an example, we will present a study, developed in the frame of a program dedicated to simulations of Titan’s atmosphere, on methane photolysis at Lyman alpha (121.6 nm). …

Formation Of Hcn And Nh3 As Primary Compounds Of Titan’S Atmosphere Simulations Using N2-Ch4 Afterglow Plasma’’, M-C. Gazeau, Y. Bénilan, E. Arzoumanian, Et. Es-Sebbar, A. Jolly, C.D. Pintassilgo

Dr. Et-touhami Es-sebbar

No abstract provided.

Ozone Profile Observations In Houston, Texas (1994 - 2010) From Aircraft, Balloons, And Satellites, Gary A. Morris, Barry Lefer, Bernhard Rappenglueck, Christine Haman, Christopher Boxe, Scott Hersey, Valerie Thouret, Jean-Pierre Cammas, Bryan Johnson, Samuel Oltmans

Gary A. Morris

Houston, Texas has long been an urban area plagued with high levels of surface ozone, particularly in spring and late summer. The combination of a large commuter population and one of the largest concentrations of petrochemical plants in the world results in abundant and nearly co-located sources of NOx and hydrocarbons. The location of Houston on the South Coast of the United States in a subtropical climate results in meteorological conditions that favor ozone production. Using MOZAIC (1994 - 2004), ozonesonde (2000, 2004 - 2010), and TES (2005 – 2010) data, we examine the evolution of ozone profiles over Houston …

Discovery Of The First Τ Sco Analogues: Hd 66665 And Hd 63425., V. Petit, D. L. Massa, W. L. F. Marcolinino, G. A. Wade, R. Ignace

Richard Ignace

The B0.2 V magnetic star τ Sco stands out from the larger population of massive OB stars due to its high X-ray activity, peculiar wind diagnostics and highly complex magnetic field. This Letter presents the discovery of the first two τ Sco analogues – HD 66665 and HD 63425, identified by the striking similarity of their ultraviolet (UV) spectra to that of τ Sco. ESPaDOnS spectropolarimetric observations were secured by the Magnetism in Massive Stars CFHT Large Program, in order to characterize the stellar and magnetic properties of these stars. cmfgen modelling of optical ESPaDOnS spectra and archived IUE UV …

Color And Stellar Population Gradients In Passively Evolving Galaxies At Z~2 From Hst/Wfc3 Deep Imaging In The Hubble Ultra Deep Field, Yicheng Guo, Mauro Giavalisco, Paolo Cassata, Henry C. Ferguson, Mark Dickinson, Alvio Renzini, Anton Koekemoer, Norman A. Grogin, Casey Papovich, Elena Tundo, Adriano Fontana, Jennifer M. Lotz, Sara Salimbeni

Mauro Giavalisco

We report the detection of color gradients in six massive (stellar mass > 10^{10} M_{sun}) and passively evolving (specific SFR < 10^{-11}/yr) galaxies at redshift 1.3

Condensation States And Landscaping With The Theory Of Abstraction, Subhajit Kumar Ganguly

Subhajit Kumar Ganguly

The Abstraction theory is applied in landscaping. A collection of objects may be made to be vast or meager depending upon the scale of observations. This idea may be developed to unite the worlds of the great vastness of the universe and the minuteness of the sub-atomic realm. Keeping constant a scaling ratio for both worlds, these may actually be converted into two self-same representatives with respect to scaling. The Laws of Physical Transactions are made use of to study Bose-Einstein condensation. As the packing density of concerned constituents increase to a certain critical value, there may be evolution of …

Abstraction In Theory - Laws Of Physical Transactions, Subhajit Kumar Ganguly

Subhajit Kumar Ganguly

Considering transport or tendency of transport of physical entities from an initial to a final point,we come to a similar basis of understanding of various physical phenomena.The trajectory-behaviour of such transport represents the effect or field of influence.This way,we may explain cluster-formation in the universe,an expanding universe,etc.This may also lead to a similar basis for understanding the four non-contact forces of nature.Also,for different ranges of acceleration in the field formed in spacetime,we have different properties of matter interacting.This may explain the difference in ranges of the various forces.

Analyzing The Role Of Icts In The Tunisian And Egyptian Unrest From An Information Warfare Perspective, Brett Van Niekerk, Kiru Pillay, Manoj Maharaj

Manoj Maharaj

In January 2011, the Tunisian government stepped down after weeks of protests; this was followed by unrest and protests in Egypt against the Egyptian government, leading also to the resignation of its president. Demonstrations in both countries were facilitated in some part by the online social media and related information and communications technologies that impacted the flow of information. The manner in which the information and communication technologies were employed suggests that the uprisings were a form of social information warfare. To provide an alternative understanding of the role of technology and information in the events that led to the …

The Information Warfare Lifecycle Model, Manoj Maharaj, Brett Van Nikerk

Manoj Maharaj

No abstract provided.

Strategic Planning For Digital Convergence In South African Businesses, Manoj Maharaj, Kiru Pillay

Manoj Maharaj

No abstract provided.

A Wfc3 Study Of Globular Clusters In Ngc 4150 - An Early-Type Minor Merger, Sugata Kaviraj, R. Mark Crockett, Bradley C. Whitmore, Joseph Silk, Robert W. O'Connell, Rogier A. Windhorst, Max Mutchler, Marina Rejkuba, Sukyoung Yi, Jay A. Frogel, Daniela Calzetti

Daniela Calzetti

We combine near-ultraviolet (NUV; 2250 {\AA}) and optical (U, B, V, I) imaging from the Wide Field Camera 3 (WFC3), on board the Hubble Space Telescope (HST), to study the globular cluster (GC) population in NGC 4150, a sub-L* (M_B ~ -18.48 mag) early-type minor-merger remnant in the Coma I cloud. We use broadband NUV-optical photometry from the WFC3 to estimate individual ages, metallicities, masses and line-of-sight extinctions [E_(B-V)] for 63 bright (M_V < -5 mag) GCs in this galaxy. In addition to a small GC population with ages greater than 10 Gyr, we find a dominant population of clusters with ages centred around 6 Gyr, consistent with the expected peak of stellar mass assembly in faint early-types residing in low-density environments. The old and intermediate-age GCs in NGC 4150 are metal-poor, with metallicities less than 0.1 ZSun, and reside in regions of low extinction (E_(B-V) < 0.05 mag). We also find a population of young, metal-rich (Z > 0.3 ZSun) clusters that have formed within the last Gyr and reside in relatively dusty (E_(B-V) > 0.3 mag) regions that are coincident with the part of the …

The Herschel M33 Extended Survey (Herm33es): Pacs Spectroscopy Of The Star Forming Region Bclmp 302, B. Mookerjea, C. Kramer, C. Buchbender, M. Boquien, S. Verley, M. Relaño, G. Quintana-Lacaci, S. Aalto, J. Braine, Daniela Calzetti, F. Combes, S. Garcia-Burillo, P. Gratier, C. Henkel, F. Israel, S. Lord, T. Nikola, M. Rölling, G. Stacey, F. S. Tabatabaei, F. Van Der Tak, P. Van Der Werf

Daniela Calzetti

Context: The emission line of [CII] at 158 micron is one of the strongest cooling lines of the interstellar medium (ISM) in galaxies. Aims: Disentangling the relative contributions of the different ISM phases to [CII] emission, is a major topic of the HerM33es program, a Herschel key project to study the ISM in the nearby spiral galaxy M33. Methods: Using PACS, we have mapped the emission of [CII] 158 micron, [OI] 63 micron, and other FIR lines in a 2'x2' region of the northern spiral arm of M33, centered on the HII region BCLMP302. At the peak of H-alpha emission, …

How Do Star-Forming Galaxies At Z>3 Assemble Their Masses?, Kyoung-Soo Lee, Henry C. Ferguson, Tommy Wiklind, Tomas Dahlen, Mark E. Dickinson, Mauro Giavalisco, Normin Grogin, Casey Papovich, Hugo Messias, Yicheng Guo, Lihwai Lin

Mauro Giavalisco

We investigate how star-forming galaxies typically assemble their masses at high redshift. Using the deep multi-wavelength coverage of the GOODS dataset, we measure stellar mass of a large sample of star-forming galaxies at z~4 and 5, and make a robust determination of stellar mass function (SMF). We report a broad correlation between stellar mass and UV luminosity, such that more UV-luminous galaxies are, on average, more massive. However, the correlation has a substantial intrinsic scatter evidenced by a non-negligible number of UV-faint but massive galaxies. Furthermore, the low-mass end of the SMF does not rise as steeply as the UV …

Variation In The Dust Spectral Index Across M33, Fatemeh S. Tabatabaei, Jonathan Braine, Carsten Kramer, Manolis Xilouris, Mederic Boquien, Simon Verley, Eva Schinnerer, Daniela Calzetti, Francoise Combes, Frank Israel, Christian Henkel, The Herm33es Team

Daniela Calzetti

Using the Herschel PACS and SPIRE FIR/submm data, we investigate variations in the dust spectral index $\beta$ in the nearby spiral galaxy M33 at a linear resolution of 160 pc. We use an iteration method in two different approaches, single and two-component modified black body models. In both approaches, $\beta$ is higher in the central disk than in the outer disk similar to the dust temperature. There is a positive correlation between $\beta$ and Halpha as well as with the molecular gas traced by CO(2-1). A Monte-Carlo simulation shows that the physical parameters are better constrained when using the two-component …