42,644 research outputs found
Equation of state of matter at supernuclear density
Vector meson model state equation to describe matter at supernuclear density - gravitational collaps
On the origin of structure in the universe
Instability hypothesis versus primordial structure hypothesis to explain origin of univers
Cosmology without general relativity
Idealizations in cosmology with special theory of relativity - partitioned universe, microcosmic model, and similarity to Newtonian cosmolog
The nonsingular origin of the universe
Qualitative arguments against theory of singular origin of univers
Advanced refractory alloy corrosion loop program quarterly progress report no. 1, quarter ending jul. 15, 1965
Material procurement and quality assurance for advanced refractory alloy corrosion loop progra
Gamma-Ray Bursts and the Cosmic Star Formation Rate
We have tested several models of GRB luminosity and redshift distribution
functions for compatibility with the BATSE 4B number versus peak flux relation.
Our results disagree with recent claims that current GRB observations can be
used to strongly constrain the cosmic star formation history. Instead, we find
that relaxing the assumption that GRBs are standard candles renders a very
broad range of models consistent with the BATSE number-flux relation. We
explicitly construct two sample distributions, one tracing the star formation
history and one with a constant comoving density. We show that both
distributions are compatible with the observed fluxes and redshifts of the
bursts GRB970508, GRB971214, and GRB980703, and we discuss the measurements
required to distinguish the two models.Comment: 12 pages, 2 postscript figures, uses AAS LaTex macros v4.0. To be
published in Astrophysical Journal Letters, accepted August 20, 1998. Revised
for publicatio
Polymeric foams from cross-linkable poly-N-ary lenebenzimidazoles
Foamed cross-linked poly-N-arylenebinzimidazoles are prepared by mixing an organic tetraamine and an ortho substituted aromatic dicarboxylic acid anhydride in the presence of a blowing agent, and then heating the prepolymer to a temperature sufficient to complete polymerization and foaming of the reactants. In another embodiment of the process, the reactants are heated to form a prepolymer. The prepolymer is then cured at higher temperatures to complete foaming and polymerization
Spitzer Observations of Black Hole Low-mass X-ray Binaries: Assessing the Non-stellar Infrared Component
We have combined ground-based optical and near-infrared data with Spitzer Space Telescope mid-infrared data for five black hole (BH) soft X-ray transients (SXTs) in order to determine the levels of near- and mid-infrared emission from sources other than the secondary star. Mid-infrared emission from an accretion disk, circumbinary dust, and/or a jet could act as sources of near-infrared contamination, thereby diluting ellipsoidal variations of the secondary star and affecting determined BH mass estimates. Based on optical to mid-infrared spectral energy distribution modeling of the five SXTs along with the prototype, V616 Mon, we detected mid-infrared excesses in half of the systems, and suggest that the excesses detected from these systems arise from non-thermal synchrotron jets rather than circumbinary dust disks
Spatial Relationship between Solar Flares and Coronal Mass Ejections
We report on the spatial relationship between solar flares and coronal mass
ejections (CMEs) observed during 1996-2005 inclusive. We identified 496
flare-CME pairs considering limb flares (distance from central meridian > 45
deg) with soft X-ray flare size > C3 level. The CMEs were detected by the Large
Angle and Spectrometric Coronagraph (LASCO) on board the Solar and Heliospheric
Observatory (SOHO). We investigated the flare positions with respect to the CME
span for the events with X-class, M-class, and C-class flares separately. It is
found that the most frequent flare site is at the center of the CME span for
all the three classes, but that frequency is different for the different
classes. Many X-class flares often lie at the center of the associated CME,
while C-class flares widely spread to the outside of the CME span. The former
is different from previous studies, which concluded that no preferred flare
site exists. We compared our result with the previous studies and conclude that
the long-term LASCO observation enabled us to obtain the detailed spatial
relation between flares and CMEs. Our finding calls for a closer flare-CME
relationship and supports eruption models typified by the CSHKP magnetic
reconnection model.Comment: 7 pages; 4 figures; Accepted by the Astrophysical Journa
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