The nearby isolated neutron stars are a group of seven relatively slowly rotating neutron stars that show thermal X-ray spectra, most with broad absorption features. They are interesting both because they may allow one to determine fundamental neutron-star properties by modeling their spectra, and because they appear to be a large fraction of the overall neutron-star population. Here, we descri...

This paper reports the design, making and characterisation of a series of Fe-based bulk metallic glass alloys with the aim of achieving the combined properties of high neutron absorption capability and sufficient glass forming ability. Synchrotron X-ray diffraction and pair distribution function methods were used to characterise the crystalline or amorphous states of the samples. Neutron transm...

Context. The discovery of photospheric absorption lines in XMM-Newton spectra of the X-ray bursting neutron star in EXO 0748−676 by Cottam and collaborators allows us to constrain the neutron star mass-radius ratio from the measured gravitational redshift. A radius of R = 9 − 12 km for a plausible mass range of M = 1.4 − 1.8 M⊙ was derived by these authors. Aims. It has been claimed that the ab...

Resonant absorption can be used as a filter for high energy neutron spectroscopy. Here we report the transmission of eight thin foil filters: erbium, indium, iridium, dysprosium, hafnium, gadolinium, cadmium and samarium, measured using neutron time-of-flight techniques over a range of energies (1 meV to 10 eV). Measured transmission is converted into energy-dependent absorption cross-section w...

We study several effects that influence the strength of the proton cyclotron and atomic features in the thermal spectra of magnetic neutron stars. We show that it is possible for vacuum polarization to strongly suppress the spectral lines when the magnetic field B & 10 G. For weaker fields (B . 7× 10 G), the surface spectrum is unaffected by vacuum polarization; thus the proton cyclotron absorp...

Two broad absorption features were discovered in the Chandra/ACIS spectrum of the isolated neutron star 1E1207.4-5209 (Sanwal et al. 2002). Expanding on our previous paper (Hailey & Mori 2002), we describe the atomic physics methodology which leads to the identification of this neutron star’s atmospheric composition. The solution of Schrödinger’s equation in an intense magnetic field combined w...

Broad relativistic iron lines from neutron star X-ray binaries are important probes of the inner accretion disk. The X-ray reflection features can be weakened due to strong magnetic fields or very low iron abundances such as is possible in X-ray binaries with low mass, first generation stars as companions. Here we investigate the reality of the broad iron line detected earlier from the neutron ...

A collection of routines calculating neutron scattering and absorption cross sections on the basis of crystal structure descriptions is presented and implemented into the new and reusable nxs program library. An example program providing a graphical user interface to the nxs functions is created to demonstrate their usage. The flexibility of the library and the possibilities for multiple areas ...

We use the three-body model and the sudden approximation to compute angular correlations in high-energy fragmentation reactions of two-neutron halos on light targets. The contribution from one-neutron absorption by far dominates over that of neutron scattering. We use He (n1n1a) and Li (n1n1Li) as examples and study the dependence of the predictions of this model on different physical assumptio...