TeV Neutrinos from Successful and Choked Gamma-Ray Bursts

Core collapse of massive stars resulting in a relativistic fireball jet which breaks through the stellar envelope is a widely discussed scenario for gamma-ray burst production. For very extended or slow rotating stars, the fireball may be unable to break through the envelope. Both penetrating and choked jets will produce, by photo-meson interactions of accelerated protons, a burst of neutrinos with energies in excess of 5 TeV while propagating in the envelope. The predicted flux, from both penetrating and chocked fireballs, should be easily detectable by planned cubic kilometer neutrino telescopes.Comment: Phys.Rev.Letters, in press, final version accepted 8/31/01 (orig. 3/17/01

Galactic Anisotropy as Signature of ``Top-Down'' Mechanisms of Ultra-High Energy Cosmic Rays

We show that ``top-down'' mechanisms of Ultra-High Energy Cosmic Rays which involve heavy relic particle-like objects predict Galactic anisotropy of highest energy cosmic rays at the level of minimum $\sim 20$. This anisotropy is large enough to be either observed or ruled out in the next generation of experiments.Comment: 8 pages, 1 figure, LaTeX. Final version appeared in Pisma Zh. Eksp. Teor. Fi

Time dependent numerical model for the emission of radiation from relativistic plasma

We describe a numerical model constructed for the study of the emission of radiation from relativistic plasma under conditions characteristic, e.g., to gamma-ray bursts (GRB's) and active galactic nuclei (AGN's). The model solves self consistently the kinetic equations for e^\pm and photons, describing cyclo-synchrotron emission, direct Compton and inverse Compton scattering, pair production and annihilation, including the evolution of high energy electromagnetic cascades. The code allows calculations over a wide range of particle energies, spanning more than 15 orders of magnitude in energy and time scales. Our unique algorithm, which enables to follow the particle distributions over a wide energy range, allows to accurately derive spectra at high energies, >100 \TeV. We present the kinetic equations that are being solved, detailed description of the equations describing the various physical processes, the solution method, and several examples of numerical results. Excellent agreement with analytical results of the synchrotron-SSC model is found for parameter space regions in which this approximation is valid, and several examples are presented of calculations for parameter space regions where analytic results are not available.Comment: Minor changes; References added, discussion on observational status added. Accepted for publication in Ap.

Solicitors General Panel on the Legacy of the Rehnquist Court

All of us who are speaking probably share the same giddy feeling in front of a microphone with no red light. For years, my daughter told people that the greatest threat to Western civilization was her father at a podium without a red light. Before becoming Solicitor General, I spent my career as a trial lawyer, arguing only a few appeals. I found this red light tradition a little peculiar. More often than not, timers and lights in courts of appeals are viewed as advisory at best. I\u27ve had arguments where ten minutes were allocated per side, and yet argument extended until the afternoon. In another case that allocated ninety minutes per side and began at nine o\u27clock, we didn\u27t actually finish until four o\u27clock in the afternoon. So coming into the SG\u27s office, my view about the red light was, well, perhaps it shows your time has nominally expired, but undoubtedly the Justices will have other questions. And in any event, I might want to take a few extra minutes to address additional points. That was so wrong. The red light ended everything-absolutely everything-and not just for the advocates; it also ended the questioning of the Associate Justices. The Chief Justice was an equal opportunity cutter-offer. On many occasions, he cut off oral argument when a Justice was at the outset of a question he or she had been trying to get out in the open oral combat that was advocacy in the Supreme Court of Chief Justice Rehnquist

Statistics of clustering of ultra-high energy cosmic rays and the number of their sources

Observation of clustering of ultra-high energy cosmic rays (UHECR) suggests that they are emitted by compact sources. Assuming small deflection of UHECR during the propagation, the statistical analysis of clustering allows to estimate the spatial density of the sources, h, including those which have not yet been observed directly. When applied to astrophysical models involving extra-galactic sources, the estimate based on 14 events with energy E>10^{20} eV gives h ~ 6 X 10^{-3} Mps^{-3}. With increasing statistics, this estimate may lead to exclusion of the models which associate the production of UHECR with exceptional galaxies such as AGN, powerful radio-galaxies, dead quasars, and models based on gamma ray bursts.Comment: The version accepted for publication in Phys. Rev. Lett. Notations changed to conventional ones. The estimate of the effective GZK radius replaced by the result of numerical simulatio

On the Neutrino Flux from Gamma-Ray Bursts

Observations imply that gamma-ray bursts (GRBs) are produced by the dissipation of the kinetic energy of a highly relativistic fireball. Photo-meson interactions of protons with gamma-rays within the fireball dissipation region are expected to convert a significant fraction of fireball energy to >10^14 eV neutrinos. We present an analysis of the internal shock model of GRBs, where production of synchrotron photons and photo-meson neutrinos are self-consistently calculated, and show that the fraction of fireball energy converted to high energy neutrinos is not sensitive to uncertainties in fireball model parameters, such as the expansion Lorentz factor and characteristic variability time. This is due in part to the constraints imposed on fireball parameters by observed GRB characteristics, and in part to the fact that for parameter values for which the photo-meson optical depth is high (implying high proton energy loss to pion production) neutrino production is suppressed by pion and muon synchrotron losses. The neutrino flux is therefore expected to be correlated mainly with the observed gamma-ray flux. The time averaged neutrino intensity predicted by the model, ~10^-8.5 GeV/cm^2 s sr, is consistent with the flux predicted by the assumption that GRBs are the sources of >10^19 eV cosmic-rays.Comment: 17 pages, 7 ps-figures. Submitted to Ap

Rex E. Lee Conference on the Office of the Solicitor General of the United States: Panel for Former Solicitors General

I agree entirely that the chain of command is clear and that the Framers managed to make it all the way through all the articles of the Constitution without even conceiving of a solicitor general, let alone bothering to mention an attorney general. It is important nonetheless to distinguish between those things the solicitor general does pursuant to the longstanding notice-and-comment regulation, and the other things a solicitor general may do pursuant to his (and, someday, her!) statutory obligation to be of general assistance to the attorney general

Evolutionary branching in a stochastic population model with discrete mutational steps

Evolutionary branching is analysed in a stochastic, individual-based population model under mutation and selection. In such models, the common assumption is that individual reproduction and life career are characterised by values of a trait, and also by population sizes, and that mutations lead to small changes in trait value. Then, traditionally, the evolutionary dynamics is studied in the limit of vanishing mutational step sizes. In the present approach, small but non-negligible mutational steps are considered. By means of theoretical analysis in the limit of infinitely large populations, as well as computer simulations, we demonstrate how discrete mutational steps affect the patterns of evolutionary branching. We also argue that the average time to the first branching depends in a sensitive way on both mutational step size and population size.Comment: 12 pages, 8 figures. Revised versio

Temperature dependence of the nitrogen-vacancy magnetic resonance in diamond

The temperature dependence of the magnetic resonance spectra of nitrogen-vacancy (NV-) ensembles in the range of 280-330 K was studied. Four samples prepared under different conditions were studied with NV- concentrations ranging from 10 ppb to 15 ppm. For all of these samples, the axial zero-field splitting (ZFS) parameter, D, was found to vary significantly with temperature, T, as dD/dT = -74.2(7) kHz/K. The transverse ZFS parameter, E, was non-zero (between 4 and 11 MHz) in all samples, and exhibited a temperature dependence of dE/(EdT) = -1.4(3) x 10^(-4) K^(-1). The results might be accounted for by considering local thermal expansion. The observation of the temperature dependence of the ZFS parameters presents a significant challenge for room-temperature diamond magnetometers and may ultimately limit their bandwidth and sensitivity.Comment: 5 pages, 2 figures, 1 tabl

High Energy Neutrinos from Astrophysical Sources: An Upper Bound

We show that cosmic-ray observations set a model-independent upper bound to the flux of high-energy, > 10^14 eV, neutrinos produced by photo-meson (or p-p) interactions in sources of size not much larger than the proton photo-meson (or pp) mean-free-path. The bound applies, in particular, to neutrino production by either AGN jets or GRBs. This upper limit is two orders of magnitude below the flux predicted in some popular AGN jet models, but is consistent with our predictions from GRB models. We discuss the implications of these results for future km^2 high-energy neutrino detectors.Comment: Added discussion showing bound cannot be evaded by invoking magnetic fields. Accepted Phys Rev