Session G1: Astrophysics and Gravity

Cosmological Simulations of Galaxy Formation

How did the Milky Way form? Was its disk assembled in a unique event or over several billion of years? Is the Milky Way surrounded by a swarm of invisible galactic satellites mainly composed of dark matter? Why the oldest stars reside and the center of the most massive galaxies? The advent of massively parallel supercomputers and large surveys by the Hubble Space Telescope and the other Great Observatories have recently allowed major breakthroughs in our understanding of how galaxies form and provide some first, tantalizing answers to these outstanding questions. I will review some of the most recent results in this exciting field.   

Observational Cosmology from the Local Group of Galaxies

In recent years there has been tremendous advance in our understanding of the galaxy formation process. Detailed observations of individual galaxies are key to the successful development of these theories, by providing a test-bed against which models are compared. The Local Group of galaxies, consisting of the Milky Way, Andromeda and some 35 or so dwarf systems, are the closest galaxies to us. They provide us with the opportunity to study the detailed structure and evolution of a range of `typical' galaxies through the analysis of their resolved stellar components. In the same way as fossils preserved in rocks tell us about the Earth's history, so too can fossils preserved in the motions and chemical signatures of stars tell us about the formation and evolutionary history of these galaxies. In this talk I will review some of the most recent observational studies of these objects and present some new results which show how the Local Group is providing unique insight into the fundamental problem of galaxy formation.   

Emission Line Observations of Ionized Gas in Isolated, Compact High-Velocity Interstellar Clouds

The interstellar medium is just as important as stars when considering how galaxies such as our own evolve. A better understanding of the interstellar medium, including a subset of clouds at anomalously high velocities (known as high-velocity clouds or HVCs), promises to shed some light on this process. It may be that the high-velocity interstellar material associated with the 21-cm radiation of neutral hydrogen is evidence that the Milky Way is not fully mature, but rather in an ongoing formative process. Although some high-velocity clouds have been shown to be located within the galactic sphere, propositions have been made that some compact and isolated HVCs may actually be massive intergalactic clouds. I used the Wisconsin H$\alpha $ Mapper (WH$\alpha $M), a telescope specifically designed to detect the faint emissions of ionized gas in the diffuse interstellar medium, to measure the levels of ionized hydrogen, nitrogen, sulfur, and doubly ionized oxygen in a sample of compact, isolated clouds. This information can be used to approximate the cloud's distance from the Milky Way's galactic plane. The majority of the sampled HVCs exhibited weak, yet detectable hydrogen emission, which is bright enough to indicate that those clouds are not intergalactic. However, three of the clouds yielded non-detections, providing tight upper limits on the metagalactic ionizing flux.   

WMAP: A Radiological Analysis II.

WMAP images have an exceedingly low signal to noise (just in excess of 1). Final images are made from 12 section images, which in turn are processed using separate linear combinations of data. ILC coefficients do not remain constant from year to year. In contrast to standard practices in medicine, difference images are presented at substantially reduced resolution. ILC images are not presented for year 2 and 3. Rather, year-1 data is signal averaged in the 3 year data set. Proper tests of reproducibility require viewing separate yearly ILC images. Fluctuations arise from the inability to properly remove the galactic foreground and in the significant yearly variations in the foreground itself. Variations in the map outside the galactic plane are significant, preventing any cosmological analysis due to yearly changes. This occurs despite the masking more than 300 image locations. Any ``signal'' observed by WMAP is simply the result of foreground effects not only from our galaxy, but indeed yearly variations from every galaxy in the universe. Contrary to published analysis, the argument suggests there are no findings in these images other than those related to image processing, yearly galactic variability and point sources.   

Using di quark scalar fields for a cosmological constant permitting gravitons escaping from early universe branes

We construct a model showing how a di quark condensate leads to a cosmological constant in line with known physical observations instead of the huge value obtained via Quantum Chromodynamics We apply Abbots criteria of a bound for the cosmological constant without his enormous tunneling time value which effectively caused his model to be abandoned as unworkable in the mid 1980s. We use a phase transition bridge from a tilted washboard potential to the chaotic inflationary model pioneered by Guth which is congruent with the slow roll criteria. This permits a physically intuitive criteria for initiation of graviton production from a domain wall formed after a transition to a chaotic inflationary potential. We believe our construction answers why gravitons would be so hard to find in typical post inflationary cosmological conditions while pointing to their de facto existence in de Sitter metric cosmology. In addition, our criterion for graviton production is in tandem with the creation of cold dark matter, indirectly observed in present day cosmology.   

The Derivation of the Elastic-Constants of the Space Medium and the Speed of Light in the Universe

Space is modeled as an elastic medium for spherical, scalar, quantum-waves. The constants of elasticity and inertia of this medium are found from the scalar compression length of space and the rest-energy of the electron `particle' using astronomical measurements of the Hubble Universe. This electron structure is the superposition of converging and diverging solutions of the scalar wave equation. These two constants of space are then used in the conventional way to derive the speed of the scalar quantum waves in this medium. The Speed is found to be = 2.2 x 10$^{8}$ meters/second, close to the measured speed of light, c, within the errors of measuring the Hubble Universe. It is concluded: 1) that the origin of c, like the origin of all natural laws, is a property of the quantum Wave Structure of matter (WSM). And 2) that, the rest-energy, or frequency, of the wave-centered ``particles'' that we observe are dependent on the potential energy of compression in the fabric of the quantum space of the Universe.   

Can magnetic waves in the auroral region transform into acoustic waves?

Aurorae are caused by geomagnetic storms created by magnetic storms from the Sun (Akasofu, 1991). ~These storms drive magnetic waves in the magnetosphere (Cornilleau-Wehrlin, 2000).~ Infrasonic waves have been observed to emanate from aurorae (Wilson and Olson, 2005).~ This suggests that magnetic waves in Earth's upper atmosphere may drive infrasound in Earth's lower atmosphere. Similar processes have been demonstrated in reverse in the Sun's atmosphere (Johnson, et al., 2002; Bogdan, et al., 2000, 2002, 2003).~ Using techniques from solar magnetohydrodynamics (MHD), we have shown that atmospheric pressure and magnetic pressure are comparable (plasma beta = 1) at 120 km, well within the auroral region, above Fairbanks, AK (Maxwell and Zita, 2005).~ This is an important condition for MHD wave transformations to occur (Bogdan, et al., 2003).~ We have also proposed mechanisms for the creation of infrasonic waves from electromagnetic waves (Maxwell and Zita, 2005).~ Now, we investigate evidence and data from satellite and ground-based instruments to test our hypotheses.   

Solar Magnetism and Effects on Earth

Will the next solar maximum cause the biggest magnetic storms in our lifetime? What is at the heart of the Sun's magnetic dynamics? What effects can this have on Earth? Dikpati's solar dynamo model (2004) shows how flows and magnetic fields interact with each other nonlinearly in the Sun's convection zone, and predicts details of the Sun's magnetic dynamics (Zita et al. 2005). Our current ``solar minimum'' is the calm before the storm. Around 2011, sunspots, solar flares, and coronal mass ejections will increase in number and intensity, as the Sun reverses its magnetic field. We will discuss why the Sun's magnetic field reverses each decade, and how these reversals affect space weather and life on Earth. Finally, we will address the model's recent prediction that the coming peak in solar magnetic activity could cause the most intense magnetic storms on Earth since 1958 (Dikpati et al. 2006).   

Discovering the Dilaton particle with the Cosmic Compass experiment

The cosmic compass experiment measures the one-way group velocity of light. It also measures a Morse function critical point that is modeled as a bulk dilaton caustic in Anti de Sitter (AdS) spacetime under the strong Maldacena conjecture. And it also measures the renormalization length exponent showing that dilaton gravity is strong at the Planck scale but decouples at low temperature proving the 't Hooft-Susskind holographic hypothesis. The discovered strong Maldacena duality is the similarity between the Nyquist sample spacing in bulk general relativity with its IR cutoff and the Planck length in brane Shannon Statistical Topological Quantum Field Theory (SSTQFT) with its UV cutoff. The discovered bulk dilaton caustic supports a microscopic wormhole on the brane that conveniently causes the cosmic compass experiment to produce sidereal data.