94,959 research outputs found
Gamma-Ray Pulsar Studies with GLAST
Some pulsars have their maximum observable energy output in the gamma-ray
band, offering the possibility of using these high-energy photons as probes of
the particle acceleration and interaction processes in pulsar magnetospheres.
After an extended hiatus between satellite missions, the recently-launched
AGILE mission and the upcoming Gamma-ray Large Area Space Telescope (GLAST)
Large Area Telescope (LAT) will allow gamma-ray tests of the theoretical models
developed based on past discoveries. With its greatly improved sensitivity,
better angular resolution, and larger energy reach than older instruments,
GLAST LAT should detect dozens to hundreds of new gamma-ray pulsars and measure
luminosities, light curves, and phase-resolved spectra with unprecedented
resolution. It will also have the potential to find radio-quiet pulsars like
Geminga, using blind search techniques. Cooperation with radio and X-ray pulsar
astronomers is an important aspect of the LAT team's planning for pulsar
studies.Comment: 8 pages, 5 figures. To appear in the proceedings of "40 Years of
Pulsars: Millisecond Pulsars, Magnetars, and More", August 12-17, 2007,
McGill University, Montreal, Canad
Interpretation of the pulsed gamma ray emission from Vela
A model is proposed for the Vela pulsar in which the radio emission originates near the surface of the neutron star while the pulsed gamma ray emission is produced by synchrotron radiation near the speed of light cylinder. This model can explain the energy flux, double pulse structure, and phase shift with respect to the radio of the gamma ray emission and offers approximate quantitative predictions for other X-ray and gamma-ray fluxes
Magnetism and superconductivity in strongly correlated CeRhIn5
Specific heat studies of CeRhIn5 as functions of pressure and magnetic field
have been used to explore the relationship between magnetism and unconventional
superconductivity, both of which involve the 4f electron of Ce. Results of
these studies cannot be understood as a simple competition for Fermi-surface
states and require a new conceptual framework.Comment: 9 pages, 7 figure
A search for quasar protoclusters at z greater than 4
In the CDM and many other hierarchical scenarios for the origins of large scale structure, the existence of luminous quasars at very high redshifts (z greater than 3 or 4) is difficult to understand, unless such objects form at the very highest peaks of the density field. One then might expect a strong clustering of quasars at large redshifts. This is a generic prediction for practically any reasonable primordial density fluctuation spectrum. For CDM, Efstathiou & Rees (1988) predicted that quasars at z greater than 4 should be clustered as strongly as the bright galaxies at z approx. than 0. Cole & Kaiser (1989) suggest that z greater than 4 quasars might represent greater than or approximately = 4(sigma) peaks of the density field and thus, should be clustered more strongly than galaxies at z approximately = 0. We are performing the following experiment: a search for quasars, AGN, or other discrete objects, e.g., starforming galaxies, near known, z greater than 4 quasars. In other words, use the early quasars as markers of possible protoclusters. This is a fairly basic test of our understanding of the formation of galaxies, large-scale structure, and the origin of the first quasars themselves
Chrysler improved numerical differencing analyzer for third generation computers CINDA-3G
New and versatile method has been developed to supplement or replace use of original CINDA thermal analyzer program in order to take advantage of improved systems software and machine speeds of third generation computers. CINDA-3G program options offer variety of methods for solution of thermal analog models presented in network format
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