Norita Kawanaka

White Dwarf Pulsars as Possible Cosmic Ray Electron-Positron Factories

We suggest that white dwarf (WD) pulsars can compete with neutron star (NS) pulsars for producing the excesses of cosmic ray electrons and positrons (e{sup {+-}}) observed by the PAMELA, ATIC/PPB-BETS, Fermi, and H.E.S.S. experiments. A merger of two WDs leads to a rapidly spinning WD with a rotational energy ({approx}10{sup 50} erg) comparable to the NS case. The birth rate ({approx}10{sup -2}-10{sup -3}/yr/galaxy) is also similar, providing the right energy budget for the cosmic ray e{sup {+-}}. Applying the NS theory, we suggest that the WD pulsars can in principle produce e{sup {+-}} up to {approx}10 TeV. In contrast to the NS model, the adiabatic and radiative energy losses of e{sup {+-}} are negligible since their injection continues after the expansion of the pulsar wind nebula, and hence it is enough that a fraction {approx}1% of WDs are magnetized ({approx}10{sup 7}-10{sup 9} G) as observed. The long activity also increases the number of nearby sources ({approx}100), which reduces the Poisson fluctuation in the flux. The WD pulsars could dominate the quickly cooling e{sup {+-}} above TeV energy as a second spectral bump or even surpass the NS pulsars in the observing energy range {approx}10 GeV-1 TeV, providing a backgroundmorexa0» for the dark matter signals and a nice target for the future AMS-02, CALET, and CTA experiment.«xa0less

Cosmic-ray hardenings in light of AMS-02 data

Recent precise observations of cosmic rays (CRs) by AMS-02 experiment clearly show (1) harder spectra of helium and carbon compared to protons by

Neutrino flavor ratios modified by cosmic-ray secondary acceleration

propto R^{0.08}

Can the relativistic light-bending model explain X-ray spectral variations of Seyfert galaxies?

, and (2) concave breaks in proton and helium spectra at a rigidity

X-ray detectability of accreting isolated black holes in our Galaxy

R sim 300

Detecting Black Hole Binaries by Gaia

GV. In particular the helium and carbon spectra are exactly similar, pointing to the same acceleration site. We examine possible interpretations of these features and identify a chemically enriched region, that is, superbubbles as the most probable origin of Galactic CRs in high rigidity

Shock Acceleration of Electrons and Synchrotron Emission from the Dynamical Ejecta of Neutron Star Mergers

R>30

High-energy gamma-ray and neutrino production in star-forming galaxies across cosmic time: Difficulties in explaining the IceCube data

GV. The similar spectra of CR carbon and helium further suggest that the CRs with

Cosmic-Ray Lithium Production at the Nova Eruptions Followed by a Type Ia Supernova

R>30

Cosmic-Ray Lithium Production in the Nova Ejecta

GV originate from the supernova ejecta in the superbubble core, mixed with comparable or less amount of interstellar medium. We predict similar spectra for heavy nuclei.