Physical Sciences and Mathematics 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

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 …

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 …

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

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 …

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.

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 …

Astrophysical Mechanisms For Pulsar Spindown, Eric Addison

Eric Addison

Pulsars are astrophysical sources of pulsed electromagnetic radiation. The pulses have a variety of shapes in the time-domain, and the pulse energy generally peaks in the radio spectrum. The accepted models theorize that pulsars are rapidly rotating neutron stars with strong dipolar magnetic fields. Current models predict that rotational kinetic energy is extracted from the pulsar in the form of electromagnetic and gravitational radiation, causing it to slowly lose rotational speed, or “spin down”. This spindown can be characterized by a single value n, known as the braking index. This report will review basic characteristics of pulsars, including short treatments …

On The Clustering Of Sub-Millimeter Galaxies, Christina C. Williams, Mauro Giavalisco, Cristiano Porciani, Min S. Yun, Alexandra Pope, Kimberly S. Scott, Jason E. Austermann, Itziar Aretxaga, Bunyo Hatsukade, Kyoung-Soo Lee, Grant W. Wilson, J. Ryan Cybulski, David H. Hughes, Ryo Kawabe, Kotaro Kohno, Thushara Perera, F. Peter Schloerb

Thushara A. Perera

We measure the angular two-point correlation function of sub-millimeter galaxies (SMGs) from 1.1-millimeter imaging of the COSMOS field with the AzTEC camera and ASTE 10-meter telescope. These data yields one of the largest contiguous samples of SMGs to date, covering an area of 0.72 degrees^2 down to a 1.26 mJy/beam (1-sigma) limit, including 189 (328) sources with S/N greater than 3.5 (3). We can only set upper limits to the correlation length r_0, modeling the correlation function as a power-law with pre-assigned slope. Assuming existing redshift distributions, we derive 68.3% confidence level upper limits of r_0 < 6-8 h^-1 Mpc at …

Epoxi: Comet 103p/Hartley 2 Observations From A Worldwide Campaign ; Astrophysical Journal Letters, K. J. Meech, M. F. A'Hearn, J. A. Adams, P. Bacci, J. Bai, L. Barrera, M. Battelino, J. M. Bauer, E. Becklin, B. Bhatt, N. Biver, D. Bockelee-Morvan, D. Bodewits, H. Bohnhardt, J. Boissier, B. P. Bonev, W. Borghini, J. R. Brucato, E. Bryssinck, M. W. Buie, H. Canovas, D. Castellano, S. B. Charnley, W. P. Chen, P. Chiang, Y. J. Choi, D. J. Christian, Y. L. Chuang, Anita L. Cochran, P. Colom, M. R. Combi, I. M. Coulson, J. Crovisier, N. Dello Russo, K. Dennerl, K. Dewahl, M. A. Disanti, M. Facchini, T. L. Farnham, Y. Fernandez, H. G. Floren, U. Frisk, T. Fujiyoshi, R. Furusho, T. Fuse, G. Galli, D. A. Garcia-Hernandez, A. Gersch, Z. Getu

Erika Gibb

Early Magnetic B-Type Stars: X-Ray Emission And Wind Properties, Lidia Oskinova, Helge Todt, Richard Ignace, John Brown, Joseph Cassinelli, Wolf-Rainer Hamann

Richard Ignace

We present a comprehensive study of X-ray emission and wind properties of magnetic early B-type stars. We compile the complete sample of early B-type stars with detected magnetic fields to date and existing X-ray measurements, in order to study whether the X-ray emission can be used as a general proxy for stellar magnetism. For the first time we analyze the UV spectra of B stars with magnetic fields by means of non-LTE iron-blanketed stellar atmosphere model that account for the X-rays at the intensity and temperatures observed. The mass-loss rates inferred from the analysis of UV lines are significantly lower …