Prof Kathy Eastwood Department of Physics and Astronomy Northern Arizona University Flagstaff The highest mass stars are responsible for the existence of spiral arms, the chemical evolution of galaxies, and probably the reionization of the universe. However, the models of these stars are much more complicated and thus poorly understood compared to those of an ordinary star like the Sun. Different methods of estimating the actual masses of the most massive stars often disagree by as much as a factor of two. In this talk I will review why modeling massive stars is important to astrophysics, describe the “mass discrepancy” for the most massive stars, and discuss the efforts of myself and my collaborators to resolve this long-standing discrepancy. ------------------------------------------------------------------------- Seismology of the Sun Prof Jason Jackiewicz Department of Astronomy University of New Mexico Las Cruces Our Sun pulsates with millions of modes of vibration that allow acoustic waves to probe its interior. Helioseismology is a set of tools that measures and interprets these oscillations, analogous to terrestrial seismology. Local helioseismology aims to make tomographic images of the solar interior at high spatial and temporal resolution that involves cross-correlation techniques, hydrodynamic modeling, and inversion methods. Obtaining three-dimensional images over long periods of time of sub-surface conditions should help us understand unresolved problems such as the dynamo, sunspots, and energetic events. I will review properties of the Sun and how solar seismic data is obtained, the procedures that go into its analysis and interpretation, and give a selection of exciting results. --------------------------------------------------------------------------------- Gravitational Waves as Deformations of Embedded Einstein Spaces Salvatore Vitale University Paris VI, Pierre et Marie Courie, France Radiative solutions, i.e. gravitational waves, are of special interest as they are one of the few previsions of General Relativity still not directly experimentally verified. If directly mesured, they could confirm the Einstein's theory, or eventually show which of the alternative theories (e.g. Brans-Dicke theory) one should choose. In this talk we show how approximate radiative solutions of Einstein's equations can be constructed using small deformations of Einstein space-times embedded into a pseudo-Euclidean flat space of higher dimension. Our method is rather different from the classical approach one follows in dealing with linearized waves: instead of deforming the space-time metric, and then analyze the field equations for this deformation, we deform the host (flat) space, which, in turn, deform the embedded manifold. This has the advantage that we always work in a flat space. Additionally, the geometrical approach we follow, allows us to eliminate from the beginning the unphysical degrees of freedom (i.e. gauge). Examples and contest will be presented. --------------------------------------------------------------------------------- Richard Lebed Arizona State University "Large Nc QCD: Physics in a World of Many Colors" Quantum chromodynamics (QCD) is the accepted theory of the strong nuclear force. We briefly review how the theory was developed, and how it was learned that QCD in our world has charges occurring in three "colors." Then we consider how physics would change if there were Nc >>3 color charges. The answer is, not all that much. Indeed, a number of observed properties of strong interactions never successfully derived from ordinary QCD are immediate consequences of large Nc QCD. Finally, we show that the unambiguous footprint of the 1/Nc expansion appears in physical examples: the spectrum of ground-state baryon masses and the multiplicity and decay modes of baryon resonances. ------------------------------------------------------------------------------- Micromachined Ultrasonic Transducers: Theory and Applications and Using Ultrasound to Measure the Young’s Modulus of LIGO Mirror Coatings Dr. Ira Wygant Stanford University Ultrasound transducers convert between mechanical energy and electrical energy for frequencies between 20 kHz and over 1 GHz. Abundant applications exist for ultrasound transducers including medical imaging and therapy, nondestructive evaluation, sonar, flow measurement, acoustic microscopy, and resonators for chemical sensing. The first half of this talk will review the general theory and design methodology for piezoelectric and capacitive transducers. This review will include specific application examples of capacitive micromachined ultrasonic transducers (CMUTs), a MEMS-based capacitive transducer technology. Examples include a 2D array of 5-MHz CMUTs flip-chip bonded to a custom-designed IC for 3D medical imaging and a 50-kHz CMUT for generating directional audio using the parametric array effect. The second half of the talk will describe the method used in [1] for measuring the Young’s modulus of LIGO mirror coatings. This method uses a high-frequency (440 MHz) piezoelectric transducer to determine the mechanical reflection coefficient of a coated mirror sample relative to an uncoated sample. The relative reflection coefficient gives an estimate of the coating’s Young’s modulus. Description of the experiment will include the transducer design and fabrication, data acquisition and processing, and methods for improving the experiment. [1] D. R. M. Crooks, et al., "Experimental measurements of mechanical dissipation associated with dielectric coatings formed using SiO2, Ta2O5 and Al2O3," Classical and Quantum Gravity. ----------------------------------------------------------------------- Title: Recent Developments in the Testing of Lorentz Symmetry Quentin Bailey, Ph.D. ERAU Abstract: The laws of special relativity are encapsulated by the principle of Lorentz symmetry. To date, no significant violation of this principle has been found. Recently, there has been increasing interest in testing Lorentz symmetry with a wide variety of ever more sensitive experiments. The primary motivation is to uncover an experimental signature from an, as yet unknown, unified fundamental theory. In this talk, I will review the basic motivation for testing Lorentz symmetry, the theoretical framework used to report results called the Standard-Model Extension (SME), and the experimental work that has been performed to date. I will discuss some recent theoretical and experimental developments concerning the testing of Lorentz symmetry, including gravitational time-delay and Doppler tests. --------------------------------------------------------------------------- "Challanges in locating a Gravitational wave source with a Gravitational Wave Interferometers' network" Michele Zanolin, ERAU Gravitational waves visible to LIGO have frequency in the 10^2-10^3 range. This limits the angular resolution of the LIGO-Virgo Laser interferometers network. The main reason is that different sensors are only few wavelegnts apart. In this talk I will review existing efforts to design an optimal source localization procedure, including one of whic MZ is coauthor and that will be published in the next issue of Physical. Rev. D. -------------------------------------------------------------------------- "Radiative cooling and modeling the Crab Synchrotron Nebula" Joseph Foy, University of Arizona Models of the Crab synchrotron nebula include energy losses by radiative and adiabatic expansion, but neglect the effect of radiative losses on the flow itself. The standard approach of all such models to date is to calculate a post-shocked flow and modify only the energy equation while assuming steady state flow dynamics. Even the most recent efforts at simulating the synchrotron emission from the Crab continue to adopt this approach. Typically, these authors argue that since the radiated power is only about 10 percent of the pulsar's spin down luminosity, radiative losses should have only negligible effects on flow dynamics. This argument implicitly assumes a spherically symmetric nebula: the estimate can be as high as 20--30 percent for a more realistic wedge geometry, for example. A new, time-independent model of the Crab synchrotron nebula that incorporates radiative cooling for the first time is presented. Specifically, the relativistic magnetohydrodynamic (MHD) flow equations is first derived and then solved with radiative energy losses fully coupled to these equations from the start. The results of model calculations give plausible agreement with observations of the Crab Nebula. It is demonstrated that, for the particle energy and magnetic field values typical of the Crab, synchrotron cooling has too significant an effect upon the flow structure to be ignored. The possibility that the dynamic ``wisps" observed in the nebular flow of the Crab are due to synchrotron cooling instabilities is discussed. ---------------------------------------------------------------------- Dimitrios Psaltis U.Arizona Tucson Title: New Tests of Strong-Field General Relativity with Black Holes and Neutron Stars Abstract: In contrast to gravity in the weak-field regime, which has been subjected to numerous experimental tests, gravity in the strong-field regime is largely unconstrained by experiments. Indeed, a large class of gravity theories can be constructed that obey the Einstein equivalence principle and cannot be rejected by solar system tests, but that diverge from general relativity in the strong-field regime. I show that such theories predict black holes and neutron stars with significantly different properties than their general relativistic counterparts. I then discuss how recent observations with current telescopes have provided interesting new constraints on scalar-tensor and braneworld gravity models that are comparable to solar-system and table-top experiments. --------------------------------------------------------------------------- Christopher J. Corbally, S.J. U.Arizona Tucson http://clavius.as.arizona.edu/vo/R1024/CCorbally.html A small but intriguing group of peculiar stars are those named after their prototype, the lambda Botis star, the 11th brightest star in the constellation Botes. These lambda Botis-type stars imitate the atmospheres of older generation stars in our Galaxy, but are found where the younger stars live. The peculiarities in their spectra are subtle, and high quality data is needed to be sure of their identification. Only some 35 are presently confirmed as lambda Botis stars, and the jury is still out concerning the origin of their peculiarities. --------------------------------------------------------------------- "Molecular Hydrogen in the FUSE Translucent Lines of Sight" Dr. Brian Rachford ERAU Prescott Molecular hydrogen (H2) is the most abundant molecule in the Universe and studies of H2 are crucial for a full understanding of the physics and chemistry of interstellar clouds. A major goal of the Far Ultraviolet Spectroscopic Explorer (FUSE) was to survey H2 in a variety of interstellar clouds that are denser than those that could be probed in previous studies. I will give an overview of H2, FUSE, and the importance of these interstellar clouds before discussing the results of our study, the second half of which has just been accepted for publication. -------------------------------------------------------------- Reshaping Radio Astronomy at ERAU Ray Fobes ERAU Prescott Ray Fobes will present an overview of Radio Astronomy, discussing the types of electromagnetic radiation of interest to Radio Astronomer's with some samples of each type. He will talk on the current state of the art in radio telescope development and talk about what the ERAU Radio Astronomy observatory has now and what the near term plan is for developing a capability on campus. Ray has specialized in Space Systems development, engineering and communications. While with the US Government he has procured and installed many 20 - 25 meter ground stations which are basically radio telescopes modified for communications purposes. -------------------------------------------------------------------------- Perspectives At LHC Darrel Smith ERAU Our own Professor Darrel Smith (who was a post doc with Carlo Rubbia at the time neutral current were discovered) will tell us what are the perspectives of the new experiments that will take place at CERN in the incoming months/years. ------------------------------------------------------------------------- Nearby Galaxies in the 2 Micron All Sky Survey Nicholas A Devereux Physics Department ERAU, Prescott Nearby galaxies manifest in a variety of shapes and sizes, forming the basis of a morphological classification scheme whereby galaxies are segregated into ellipticals, lenticulars and spirals. However, recent observations with NASA's Hubble and Spitzer Space Telescopes have shown that distant galaxies at z ~ 2 are completely unrecognizable. Understanding the emergence of the Hubble sequence is central to understanding how galaxies formed, and how they changed over time into the objects recognized in the present universe. Quantifying the space density of galaxies as a function of luminosity is a key diagnostic in understanding the evolution of galaxy morphology. The local galaxy luminosity function, as defined by nearby galaxies, is the benchmark against which luminosity functions for more distant galaxies are compared. The primary objective of this paper is to present the first benchmark near infrared luminosity functions for nearby galaxies, segregated by morphological type. The results set the stage for future observations using NASA's James Webb Space Telescope.