New insight into the physical state of solar system objects

The application of IUE to observations of solar system objects is summarized and a brief survey of discoveries made during the first two years of IUE operation is given

A study of the feasibility of ultraviolet spectrometry for cometary missions

Ultraviolet spectra fo the comet West obtained by sounding rocket experiments in 1976 are reproduced and interpreted in order to estimate the expected brightness of the emission features and determine the spatial extent of these features for the proposed Halley Flyby/Tempel 2 rendezvous and the possible Halley or Encke flybys close to perihelion. A coma model was constructed and evaluated for the physical condition of candidate targets such as heliocentric distance, gas production, and composition. In addition to brightness profiles, the neutral and ion densities of the principal species are also dervied. The brightness profiles can be used to determine the feasibility of utilizing the space telescope to provide supporting observations during the mission. Basic parameters identified are spectral range, wavelength resolution, spatial resolution, sensitivity and dynamic range, rejection of scattered light, and integration or accumulation time

Rocket and laboratory studies in aeronomy and astrophysics

Progress from March 1, 1986 to August 31, 1986 is covered and includes the work performed in response to a proposal entitled A Spartan Payload for Spatially Resolved Spectroscopy of Extended Faint Sources in the Extreme Ultraviolet (EUV). During this period, one rocket was launched, the reflight of the payload to observe Halley's comet on March 13, 1986. Most of the effort during this period was concentrated on detailed mechanical and electronic design of a Spartan payload and on the reduction and analysis of the data from the two Halley rocket flights and from the UVX experiment which flew on STS-61C in January 1986

Rocket and laboratory studies in aeronomy and astronomy

Data extracted from semi-annual status reports presented include: a list of all sounding rocket launches performed under NASA sponsorship; a list of Ph.D. and M.A. degrees awarded to students who worked in these programs; a summary bibliography of all publications through 1983; the most recent list of the publications from the IUE program; a summary of instrument development supported by the Johns Hopkins sounding rocket program; and a list of faculty and post-doctoral research associates whose work was supported by this grant

Observations of the diffuse UV radiation field

Spectra are presented for the diffuse UV radiation field between 1250 to 3100 A from eight different regions of the sky, which were obtained with the Johns Hopkins UVX experiment. UVX flew aboard the Space Shuttle Columbia (STS-61C) in January 1986 as part of the Get-Away Special project. The experiment consisted of two 1/4 m Ebert-Fastie spectrometers, covering the spectral range 1250 to 1700 A at 17 A resolution and 1600 to 3100 A at 27 A resolution, respectively, with a field of view of 4 x .25 deg, sufficiently small to pick out regions of the sky with no stars in the line of sight. Values were found for the diffuse cosmic background ranging in intensity from 300 to 900 photons/sq cm/sec/sr/A. The cosmic background is spectrally flat from 1250 to 3100 A, within the uncertainties of each spectrometer. The zodiacal light begins to play a significant role in the diffuse radiation field above 2000 A, and its brightness was determined relative to the solar emission. Observed brightnesses of the zodiacal light in the UV remain almost constant with ecliptic latitude, unlike the declining visible brightnesses, possibly indicating that those (smaller) grains responsible for the UV scattering have a much more uniform distribution with distance from the ecliptic plane than do those grains responsible for the visible scattering

The Fourth Positive System of Carbon Monoxide in the Hubble Space Telescope Spectra of Comets

The rich structure of the Fourth Positive System (A-X) of carbon monoxide accounts for many of the spectral features seen in long slit HST-STIS observations of comets 153P/Ikeya-Zhang, C/2001 Q4 (NEAT), and C/2000 WM1 (LINEAR), as well as in the HST-GHRS spectrum of comet C/1996 B2 Hyakutake. A detailed CO fluorescence model is developed to derive the CO abundances in these comets by simultaneously fitting all of the observed A-X bands. The model includes the latest values for the oscillator strengths and state parameters, and accounts for optical depth effects due to line overlap and self-absorption. The model fits yield radial profiles of CO column density that are consistent with a predominantly native source for all the comets observed by STIS. The derived CO abundances relative to water in these comets span a wide range, from 0.44% for C/2000 WM1 (LINEAR), 7.2% for 153P/Ikeya-Zhang, 8.8% for C/2001 Q4 (NEAT) to 20.9% for C/1996 B2 (Hyakutake). The subtraction of the CO spectral features using this model leads to the first identification of a molecular hydrogen line pumped by solar HI Lyman-beta longward of 1200A in the spectrum of comet 153P/Ikeya-Zhang. (Abridged)Comment: 12 pages, 11 figures, ApJ accepte

Low Mass Gluino within the Sparticle Landscape, Implications for Dark Matter, and Early Discovery Prospects at LHC-7

We analyze supergravity models that predict a low mass gluino within the landscape of sparticle mass hierarchies. The analysis includes a broad class of models that arise in minimal and in non-minimal supergravity unified frameworks and in extended models with additional $U(1)^n_X$ hidden sector gauge symmetries. Gluino masses in the range $(350-700)$ GeV are investigated. Masses in this range are promising for early discovery at the LHC at $\sqrt s =7$ TeV (LHC-7). The models exhibit a wide dispersion in the gaugino-Higgsino eigencontent of their LSPs and in their associated sparticle mass spectra. A signature analysis is carried out and the prominent discovery channels for the models are identified with most models needing only $\sim 1 \rm fb^{-1}$ for discovery at LHC-7. In addition, significant variations in the discovery capability of the low mass gluino models are observed for models in which the gluino masses are of comparable size due to the mass splittings in different models and the relative position of the light gluino within the various sparticle mass hierarchies. The models are consistent with the current stringent bounds from the Fermi-LAT, CDMS-II, XENON100, and EDELWEISS-2 experiments. A subclass of these models, which include a mixed-wino LSP and a Higgsino LSP, are also shown to accommodate the positron excess seen in the PAMELA satellite experiment.Comment: 37 pages, 8 figures, Published in PR

Comets

Spectroscopy of comets, in the X-ray and far-ultraviolet from space, and in the near infrared and millimeter from the ground, have revealed a wealth of new information, particularly about the molecular constituents that make up the volatile fraction of the comet s nucleus. Interpretation of these data requires not only proper wavelengths for identification but also information about the photolytic and excitation processes at temperatures typical of the inner coma (70-100 K) that lead to the observed spectral signatures. Several examples, mainly from Far Ultraviolet Spectroscopic Explorer and Hubble Space Telescope spectra of comets observed during the last few years, will be given to illustrate some of the current issues

Water production models for Comet Bradfield (1979 l)

The IUE observations of Comet Bradfield (1979 l) made 10 January 1980 to 3 March 1980 permit a detailed study of water production for this comet. Brightness measurements are presented for all three water dissociation products, H, O, and OH, and comparisons are made with model predictions. The heliocentric variation of the water production rate was derived

A Rigorous Proof of Fermi Liquid Behavior for Jellium Two-Dimensional Interacting Fermions

Using the method of continuous constructive renormalization group around the Fermi surface, it is proved that a jellium two-dimensional interacting system of Fermions at low temperature $T$ remains analytic in the coupling constant $\lambda$ for $|\lambda| |\log T| \le K$ where $K$ is some numerical constant and $T$ is the temperature. Furthermore in that range of parameters, the first and second derivatives of the self-energy remain bounded, a behavior which is that of Fermi liquids and in particular excludes Luttinger liquid behavior. Our results prove also that in dimension two any transition temperature must be non-perturbative in the coupling constant, a result expected on physical grounds. The proof exploits the specific momentum conservation rules in two dimensions.Comment: 4 pages, no figure