Thermal Xray emission from hot polar cap in drifting subpulse pulsars

Janusz Gil George Melikidze Bing Zhang Received 24 June 2006 Accepted 7 September 2006 Published online 27 March 2007 Springer Science+Business Media B.V. 2007 Abstract Within the framework of the partially screened inner acceleration region the relationship between the X-ray luminosity and the circulational periodicity of drifting subpulses is derived. This relationship is quite well satisfied in pulsars for which an appropriate radio and X-ray measurements exist. A special case of PSR...

Two decades of pulsar timing of Vela

Richard Dodson Dion Lewis Peter McCulloch Received 30 June 2006 Accepted 19 September 2006 Published online 20 March 2007 Springer Science+Business Media B.V. 2007 Abstract Pulsar timing at the Mt Pleasant observatory has focused on Vela, which can be tracked for 18 hours of the day. These nearly continuous timing records extend over 24 years allowing a greater insight into details of timing noise, micro glitches and other more exotic effects. In particular we report the glitch parameters of...

Instabilities in rotating relativistic stars driven by viscosity

Received 30 June 2006 Accepted 27 October 2006 Published online 20 March 2007 Springer Science+Business Media B.V. 2007 Abstract We investigate the instability driven by viscosity in rotating relativistic stars by means of an iterative approach. We focus on polytropic rotating equilibrium stars and impose an m 2 perturbation in the lapse. We vary both the stiffness of the equation of state and the compactness of the star to study these factors on the critical value T W for the instability. For...

E

Which holds for 1011 G < B < 1014 G. For 1011 G < B< 1012 G in l.h.s. Eb is the binding energy of the He+ atomic ion, otherwise Eb is the binding energy of the exotic ion He +. For 1011G < B < 1013 G in r.h.s. Eb is the binding energy of H+, otherwise Eb is the binding energy of the exotic ion H2+. - H2+ has the lowest Etotal for B > 1013G among 1e systems made from protons. - The Hydrogen atom has the highest total energy being the least bound 1e system made from protons for 0...

Studies of neutron stars at opticalIR wavelengths

De Luca G.L. Israel G. Lo Curto C. Motch R. Perna N. Rea R. Turolla Received 30 June 2006 Accepted 23 August 2006 Published online 28 March 2007 Springer Science+Business Media B.V. 2007 Abstract In the last years, optical studies of Isolated Neutron Stars (INSs) have expanded from the more classical rotation-powered ones to other categories, like the Anomalous X-ray Pulsars (AXPs) and the Soft Gamma-ray Repeaters (SGRs), which make up the class of the magnetars, the...

Info

Observing the TS radiation over a wide range of frequencies is particularly important. X-ray observations can only probe the Wein tail of the TS spectrum emitted from the NS surface. This information is insufficient to reconstruct the overall shape of the spectrum which can deviate from the simple black-body due to the presence of an atmosphere or nonuniformity of surface temperature. Chemical composition of the atmosphere can dramatically affect the X-ray spectrum (Romani 1987 Pavlov et al....

D

Where D is the distance to the source. To obtain the corresponding gravitational wave amplitude in the frequency domain we use the stationary phase approximation, h(f) h(t) J df dt , where df dt follows straightforwardly from (17), where the maximum frequency of the gravitational wave, max 1191 Hz, corresponds to the initial value of the angular velocity of the star, fiK 5612 s-1. In the previous expression, the second term on the right hand side becomes smaller than the first term after just a...

Snr 1987a

Since the launch of Chandra, SN 1987A has been the focus of a series of repeated observations (see Park et al. 2005 and references therein). One goal of these observations is to detect the emergence of the X-ray flux from a newly born compact object. Figure 13 shows a sequence of such observations from 1999 through the middle of last year. These images are a textbook demonstration of the development of the various shocks resulting from a supernova event. The images also dramatically demonstrate...

Using XMMNewton to measure the spectrum of the Vela pulsar and its phase variation

Armando Manzali Andrea De Luca Patrizia A. Caraveo Received 30 June 2006 Accepted 4 October 2006 Published online 20 March 2007 Springer Science+Business Media B.V. 2007 Abstract We report on our analysis of two XMM-Newton observations of the Vela pulsar performed in December 2000 (total exposure time 96.5 ks). We succeeded in resolving the pulsar spectrum from the surrounding bright nebular emission taking advantage both of the accurate calibration of the EPIC point spread function and of the...

Rx J185653754

RX J1856.5-3754 is the brightest of a number of ROSAT-detected objects, which are thermal emitters with blackbody temperatures in the range of 50-100 eV. These sources appear to be isolated neutron stars, and therefore RX J1856.5-3754 was a promising candidate for a long Chandra observation in the hope that spectroscopy would provide a determination of parameters such as the radius, surface gravity, and gravitational redshift all of which would lead one to the holy grail of the equation of...

Mjd

Fig. 6 Long term light curve of SGR 1806-20, as measured with IBIS. The vertical line represents the time of the giant flare of December 27 2004 20 (Mereghetti et al. 2005c Molkov et al. 2005). Up to then, spectral information on the persistent emission of SGRs was known only below 10 keV. The low energy spectrum is usually well described by the sum of a power law component and a black body. The spectrum above 20 keV is rather hard with a photon index between 1.5 and 2.0 and extends up to 150...

The example of effective plasma acceleration in a magnetosphere

Received 24 June 2006 Accepted 11 October 2006 Published online 17 March 2007 Springer Science+Business Media B.V. 2007 Abstract The problem of effective transform of Poynting flux energy into the kinetic energy of relativistic plasma outflow in a magnetosphere is considered. In this article we present an example of such acceleration. In order to perform it, we use the approach of ideal axisymmetric mag-netohydrodynamics (MHD). For highly magnetized plasma outflow we show that a linear growth...

The puzzling Xray source in RCW103

Mereghetti A. Tiengo G.F. Bignami Received 14 July 2006 Accepted 14 September 2006 Published online 24 March 2007 Springer Science+Business Media B.V. 2007 Abstract 1E 161348-5055 (1E) is a compact object lying at the center of the 2000 year old Supernova Remnant (SNR) RCW103. Its original identification as an isolated, radio-quiet neutron star has been questioned in recent years by the observation of a significant long-term variability, as well as by reports of a...

Mountains on neutron stars

Received 23 August 2006 Accepted 11 October 2006 Published online 20 March 2007 Springer Science+Business Media B.V. 2007 Abstract The aim of this work is to compare a neutron star with an accreted crust and one with a non-accreted crust, and estimate which one is potentially a better source of gravitational waves (i.e. can sustain a larger mountain). To do this we present a new formalism, and find that a non-accreted crust can sustain a slightly larger mountain. We also discuss the importance...

Precession as a probe of the neutron star interior

Received 30 June 2006 Accepted 18 October 2006 Published online 21 March 2007 Springer Science+Business Media B.V. 2007 Abstract Strong evidence that some neutron stars precess (nutate) with long periods ( 1 yr) challenges our current understanding of the neutron star interior. I describe how neutron star precession can be used to constrain the state of the interior in a new way. I argue that the standard picture of the outer core, in which superfluid neutrons coexist with type II,...

Ic 443

Historically, the first Chandra observation of the IC 443 SNR (Olbert et al. 2001) was a publicity tour-de-force as the first three authors were high school students at the time. The remnant has been the subject of many studies in different wavelength bands as there is a large variety of shocked molecular gas present due to the interaction with surrounding molecular clouds (see references in Olbert et al. 2001, and Bykov et al. 2005). IC 443 is also a candidate counterpart to the EGRET source...

Giant pulses of pulsar radio emission

Received 29 June 2006 Accepted 22 August 2006 Published online 27 March 2007 Springer Science Business Media B.V. 2007 Abstract We present a brief review of observational manifestations of pulsars with giant pulses radio emission, based on the survey of the main properties of known pulsars with giant pulses, including our detection of 4 new pulsars with giant pulses. Keywords Neutron stars Pulsars Giant pulses Giant pulses GPs , a short-duration outbursts, are a special form of pulsar radio...