WIMP Annihilation and Cooling of Neutron Stars

We study the effect of WIMP annihilation on the temperature of a neutron star. We shall argue that the released energy due to WIMP annihilation inside the neutron stars, might affect the temperature of stars older than 10 million years, flattening out the temperature at $\sim 10^4$ K for a typical neutron star.Comment: 20 pages, 2 figure

Marmara Island earthquakes, of 1265 and 1935; Turkey

The long-term seismicity of the Marmara Sea region in northwestern Turkey is relatively well-recorded. Some large and some of the smaller events are clearly associated with fault zones known to be seismically active, which have distinct morphological expressions and have generated damaging earthquakes before and later. Some less common and moderate size earthquakes have occurred in the vicinity of the Marmara Islands in the west Marmara Sea. This paper presents an extended summary of the most important earthquakes that have occurred in 1265 and 1935 and have since been known as the Marmara Island earthquakes. The informative data and the approaches used have therefore the potential of documenting earthquake ruptures of fault segments and may extend the records kept on earthquakes far before known history, rock falls and abnormal sea waves observed during these events, thus improving hazard evaluations and the fundamental understanding of the process of an earthquake

Post-Glitch RXTE-PCA Observations of the Vela Pulsar

We report the results of analysis of observations of the Vela Pulsar by PCA on RXTE. Our data consists of two parts. The first part contains observations at 1, 4, and 9 days after the glitch in 1996 and has 27000 sec. total exposure time. The second part of observations were performed three months after this glitch and have a total exposure time of 93000 sec. We found pulsations in both sets. The observed spectrum is a power-law with no apparent change in flux or count rate. The theoretical expectations of increase in flux due to internal heating after a glitch are smaller than the uncertainty of the observations.Comment: 6 pages, 5 figures in 9 ps/eps files. Accepted for publication in A&A Main Journa

Incompatibility of long-period neutron star precession with creeping neutron vortices

Aims: To determine whether ``vortex creep'' in neutron stars, the slow motion of neutron vortices with respect to pinning sites in the core or inner crust, is consistent with observations of long-period precession. Methods: Using the concept of vortex drag, I discuss the precession dynamics of a star with imperfectly-pinned (i.e., "creeping'') vortices. Results: The precession frequency is far too high to be consistent with observations, indicating that the standard picture of the outer core (superfluid neutrons in co-existence with type II, superconducting protons) should be reconsidered. There is a slow precession mode, but it is highly over-damped and cannot complete even a single cycle. Moreover, the vortices of the inner crust must be able to move with little dissipation with respect to the solid.Comment: 4 pages, v3. Missing reference adde

1881 and 1949 earthquakes at the Chios-Cesme Strait (Aegean Sea) and their relation to tsunamis

The most earthquake-prone areas in the eastern central Aegean Sea are the Izmir Bay, the Karaburun peninsula and the island of Chios. The level of seismic activity and tsunami potential are influenced by the presence of normal faults around the region. There have been about 20 moderate-size earthquakes from 496 BC to 1949 AD. Among these earthquakes, the ones on the dates 20 March 1389, 13 November 1856, 19/22 January 1866, 3 April 1881 and 23 July 1949 produced tsunamis. The Chios-Cesme earthquake (1881, Mw 6.5) took place in the South of the Cesme strait while the Chios-Karaburun earthquake (1949, Mw 6.7) occurred in the North. The tsunamis caused by the earthquakes affected the coasts of Chios Island and Cesme. These waves are thought to be associated with the earthquakes and co-seismic underwater failures possibly occurred along the coasts of the Chios Island and Karaburun Peninsula or on the complex subaqueous morphology between these lands. Some sea waves or oscillations observed following the aftershocks are believed to be related to other natural phenomena; e.g. the seiches occurred mainly in open-narrow bays as triggered by the earthquakes

The rigidity of crystalline color superconducting quark matter

We calculate the shear modulus of crystalline color superconducting quark matter, showing that this phase of dense, but not asymptotically dense, three-flavor quark matter responds to shear stress like a very rigid solid. To evaluate the shear modulus, we derive the low energy effective Lagrangian that describes the phonons that originate from the spontaneous breaking of translation invariance by the spatial modulation of the gap parameter $\Delta$. These massless bosons describe space- and time-dependent fluctuations of the crystal structure and are analogous to the phonons in ordinary crystals. The coefficients of the spatial derivative terms of the phonon effective Lagrangian are related to the elastic moduli of the crystal; the coefficients that encode the linear response of the crystal to a shearing stress define the shear modulus. We analyze the two particular crystal structures which are energetically favored over a wide range of densities, in each case evaluating the phonon effective action and the shear modulus up to order $\Delta^2$ in a Ginzburg-Landau expansion, finding shear moduli which are 20 to 1000 times larger than those of neutron star crusts. The crystalline color superconducting phase has long been known to be a superfluid -- by picking a phase its order parameter breaks the quark-number $U(1)_B$ symmetry spontaneously. Our results demonstrate that this superfluid phase of matter is at the same time a rigid solid. We close with a rough estimate of the pinning force on the rotational vortices which would be formed embedded within this rigid superfluid upon rotation. Our results raise the possibility that (some) pulsar glitches could originate within a quark matter core deep within a neutron star.Comment: 38 pages, 5 figures. v3. Two new paragraphs in Section V (Conclusion); some additional small changes. A paragraph discussing supercurrents added in Section I (Introduction). Version to appear in Phys. Rev.

The effect of realistic equations of state and general relativity on the "snowplow" model for pulsar glitches

Many pulsars are observed to "glitch", i.e. show sudden jumps in their rotational frequency $\nu$, some of which can be as large as $\Delta \nu/\nu\approx 10^{-6}-10^{-5}$ in a subset of pulsars known as giant glitchers. Recently Pizzochero (2011) has shown that an analytic model based on realistic values for the pinning forces in the crust and for the angular momentum transfer in the star can describe the average properties of giant glitches, such as the inter-glitch waiting time, the step in frequency and that in frequency derivative. In this paper we extend the model (originally developed in Newtonian gravity and for a polytropic equation of state) to realistic backgrounds obtained by integrating the relativistic equations of stellar structure and using physically motivated equations of state to describe matter in the neutron star. We find that this more detailed treatment still reproduces the main features of giant glitches in the Vela pulsar and allows us to set constraints on the equation of state. In particular we find that stiffer equations of state are favoured and that it is unlikely that the Vela pulsar has a high mass (larger than $M\approx 1.5 M_\odot$).Comment: 15 pages, 8 figures, submitted to MNRA

Tkachenko waves, glitches and precession in neutron star

Here I discuss possible relations between free precession of neutron stars, Tkachenko waves inside them and glitches. I note that the proposed precession period of the isolated neutron star RX J0720.4-3125 (Haberl et al. 2006) is consistent with the period of Tkachenko waves for the spin period 8.4s. Based on a possible observation of a glitch in RX J0720.4-3125 (van Kerkwijk et al. 2007), I propose a simple model, in which long period precession is powered by Tkachenko waves generated by a glitch. The period of free precession, determined by a NS oblateness, should be equal to the standing Tkachenko wave period for effective energy transfer from the standing wave to the precession motion. A similar scenario can be applicable also in the case of the PSR B1828-11.Comment: 6 pages, no figures, accepted to Ap&S

Damping of differential rotation in neutron stars

We derive the transport relaxation times for quasiparticle-vortex scattering processes via nuclear force, relevant for the damping of differential rotation of superfluids in the quantum liquid core of a neutron star. The proton scattering off the neutron vortices provides the dominant resistive force on the vortex lattice at all relevant temperatures in the phase where neutrons only are in the paired state. If protons are superconducting, a small fraction of hyperons and resonances in the normal state would be the dominant source of friction on neutron and proton vortex lattices at the core temperatures $T\ge 10^{7}$ K.Comment: 5 pages, Revtex, Phys. Rev. D 58, Rapid Communication, in pres