Related papers: Magnetar Outburst Models with Cooling Simulations
Slow dissipation of non-potential magnetic fields in the magnetosphere of the magnetar is assumed to accelerate particles to hundreds MeV along the magnetic field lines. We consider interaction of fast particles with the surface of the…
The dissipation of intense crustal electric currents produces high Joule heating rates in cooling neutron stars. Here it is shown that Joule heating can counterbalance fast cooling, making it difficult to infer the presence of hyperons…
Thermonuclear burning on the surface of a neutron star causes the expansion of a thin outer layer of the star, $\Delta R(t)$. The layer rotates slower than the star due to angular momentum conservation. The shear between the star and the…
Recent observations of X-ray pulsars at low luminosities allow, for the first time, to compare theoretical models for the emission from highly magnetized neutron star atmospheres at low mass accretion rates ($\dot{M} \lesssim 10^{15}$ g…
Observations of cool stars reveal dark spot-like features on their surfaces. Compared to sunspots, starspots can be bigger or cover a larger fraction of the stellar surface. While sunspots appear only at low latitudes, starspots are also…
The origins of the various outbursts of hard X-rays from magnetars (highly magnetized neutron stars) are still unknown. We identify instabilities in relativistic magnetospheres that can explain a range of X-ray flare luminosities. Crustal…
We study the thermal structure of neutron stars with magnetized envelopes composed of accreted material, using updated thermal conductivities of plasmas in quantizing magnetic fields, as well as equation of state and radiative opacities for…
There exists both theoretical and observational evidence that the magnetic field decay in neutron stars may proceed in a pronounced non--linear way during a certain episode of the neutron star's life. In the presence of a strong magnetic…
A neutron star is one of the possible end states of a massive star. It is compressed by gravity and stabilized by the nuclear degeneracy pressure. Despite its name, the composition of these objects is not exactly known. However, from the…
Magnetic storms on stars manifest as remarkable, randomly occurring changes of the luminosity over durations that are tiny in comparison to the normal evolution of stars. These stellar flares are bursts of electromagnetic radiation from…
The emission of intense radio pulses by flaring magnetars is investigated. Small-scale current gradients can be imprinted into a strongly magnetized outflow by the same processes that source fireball radiation in the closed magnetosphere.…
As neutron stars spin-down and contract, the deconfinement phase transition can continue to occur, resulting in energy release(so-called deconfinement heating) in case of the first-order phase transition. The thermal evolution of neutron…
We conduct one-dimensional stellar evolutionary numerical simulations under the assumption that an efficient dynamo operates in the core of massive stars years to months before core collapse and find that the magnetic activity enhances mass…
The giant flares produced by highly magnetized neutron stars, "magnetars," are the brightest sources of high energy radiation outside our solar system. Serendipitous observations with NASA's Rossi X-ray Timing Explorer (RXTE) of the two…
The magnetar magnetosphere is gradually twisted by shearing from footpoint motion, and stored magnetic energy also increases at the same time. When a state exceeds a threshold, flares/outbursts manifest themselves as a result of a…
We present recent work on using astronomical observations of neutron stars to reveal unique insights into nuclear matter that cannot be obtained from laboratories on Earth. First, we discuss our measurement of the rapid cooling of the…
Magnetars are slowly-rotating neutron stars with extremely strong magnetic fields ($10^{13-15}$ G), episodically emitting $\sim100$ ms long X-ray bursts with energies of $\sim10^{40-41}$ erg. Rarely, they produce extremely bright, energetic…
Thermal evolution of neutron stars is known to depend on the properties of superdense matter in neutron star cores. We suggest a statistical analysis of isolated cooling middle-aged neutron stars and old transiently accreting…
Superbursts are rare and energetic thermonuclear carbon flashes observed to occur on accreting neutron stars. We create the first multi-zone models of series of superbursts using a stellar evolution code. We self-consistently build up the…
The outburst and spin-down glitch of magnetars are modeled from the magnetospheric point of view. We try to discuss the following four questions: (1) Which pulsar on the period and peirod-derivative diagram are more likely to show magnetar…