We study thermal structure of magnetars as highly magnetized neutron stars with internal heat sou... more We study thermal structure of magnetars as highly magnetized neutron stars with internal heat sources in the crust. We show that heat does not tend spread along the surface. Most economical heaters are those placed in the outer crust in the form of hot layers (hot spots) under certain parts of the surface. The required heat intensity is consistent with Ohmic dissipation of electric currents within the heater. This dissipation of the magnetic energy, that is transported to the heater during magnetar life, can power quasi-persistent emission of magnetars.
ABSTRACT The equation of state (EOS) of dense matter is a crucial input for the neutron-star stru... more ABSTRACT The equation of state (EOS) of dense matter is a crucial input for the neutron-star structure calculations. This Fortran code can obtain a "unified EOS" in the many-body calculations based on a single effective nuclear Hamiltonian, and is valid in all regions of the neutron star interior. For unified EOSs, the transitions between the outer crust and the inner crust and between the inner crust and the core are obtained as a result of many-body calculations.
Cooling of neutron stars (NSs) with the cores composed of neutrons, protons, and electrons is ana... more Cooling of neutron stars (NSs) with the cores composed of neutrons, protons, and electrons is analyzed. The main cooling regulators are discussed: opening of direct Urca process in a NS central kernel; superfluidity of nucleons in NS interiors; surface layers of light (accreted) elements; strong surface magnetic fields. An emphasis is paid on the cooling scenario with strong $^1$S$_0$ pairing of protons and weak $^3$P$_2$ pairing of neutrons in the NS core, as well as strong $^1$S$_0$ pairing of neutrons in the NS crust. The theory predicts three types of isolated cooling middle-aged NSs with distinctly different properties: low-mass, slowly cooling NSs; medium-mass, moderately cooling NSs; massive, rapidly cooling NSs. The theory is compared with observations of isolated NSs -- pulsars and radio quiet NSs in supernova remnants. The constraints on physical properties of NSs which can be inferred from such a comparison are outlined.
Equation of state for partially ionized carbon at temperatures T approximately &a... more Equation of state for partially ionized carbon at temperatures T approximately > or = 10(5) K is calculated in a wide range of densities, using the method of free energy minimization in the framework of the chemical picture of plasmas. The free energy model includes the internal partition functions of bound species. The latter are calculated by a self-consistent treatment of each ionization stage in the plasma environment taking into account pressure ionization. The long-range Coulomb interactions between ions and screening of the ions by free electrons are included using our previously published analytical model.
We study thermal structure of magnetars as highly magnetized neutron stars with internal heat sou... more We study thermal structure of magnetars as highly magnetized neutron stars with internal heat sources in the crust. We show that heat does not tend spread along the surface. Most economical heaters are those placed in the outer crust in the form of hot layers (hot spots) under certain parts of the surface. The required heat intensity is consistent with Ohmic dissipation of electric currents within the heater. This dissipation of the magnetic energy, that is transported to the heater during magnetar life, can power quasi-persistent emission of magnetars.
ABSTRACT The equation of state (EOS) of dense matter is a crucial input for the neutron-star stru... more ABSTRACT The equation of state (EOS) of dense matter is a crucial input for the neutron-star structure calculations. This Fortran code can obtain a "unified EOS" in the many-body calculations based on a single effective nuclear Hamiltonian, and is valid in all regions of the neutron star interior. For unified EOSs, the transitions between the outer crust and the inner crust and between the inner crust and the core are obtained as a result of many-body calculations.
Cooling of neutron stars (NSs) with the cores composed of neutrons, protons, and electrons is ana... more Cooling of neutron stars (NSs) with the cores composed of neutrons, protons, and electrons is analyzed. The main cooling regulators are discussed: opening of direct Urca process in a NS central kernel; superfluidity of nucleons in NS interiors; surface layers of light (accreted) elements; strong surface magnetic fields. An emphasis is paid on the cooling scenario with strong $^1$S$_0$ pairing of protons and weak $^3$P$_2$ pairing of neutrons in the NS core, as well as strong $^1$S$_0$ pairing of neutrons in the NS crust. The theory predicts three types of isolated cooling middle-aged NSs with distinctly different properties: low-mass, slowly cooling NSs; medium-mass, moderately cooling NSs; massive, rapidly cooling NSs. The theory is compared with observations of isolated NSs -- pulsars and radio quiet NSs in supernova remnants. The constraints on physical properties of NSs which can be inferred from such a comparison are outlined.
Equation of state for partially ionized carbon at temperatures T approximately &a... more Equation of state for partially ionized carbon at temperatures T approximately > or = 10(5) K is calculated in a wide range of densities, using the method of free energy minimization in the framework of the chemical picture of plasmas. The free energy model includes the internal partition functions of bound species. The latter are calculated by a self-consistent treatment of each ionization stage in the plasma environment taking into account pressure ionization. The long-range Coulomb interactions between ions and screening of the ions by free electrons are included using our previously published analytical model.
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Papers by Alexander Potekhin