English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The soft X-ray pulsar RX J1856.5-3754 is the brightest member of a smallclass of thermally-emitting, radio-silent, isolated neutron stars. Its X-rayspectrum is almost indistinguishable from a blackbody with $kT^\infty\approx60$ eV, but evidence of harder emission above $\sim 1$ keV has been recentlyfound. We report on a spectral and timing analysis of RX J1856.5-3754 based onthe large amount of data collected by XMM-Newton in 2002--2022, complemented bya dense monitoring campaign carried out by NICER in 2019. Through aphase-coherent timing analysis we obtained an improved value of the spin-downrate $\dot{\nu}=-6.042(4)\times10^{-16}$ Hz s$^{-1}$, reducing by more than oneorder magnitude the uncertainty of the previous measurement, and yielding acharacteristic spin-down field of $1.47\times10^{13}$ G. We also detect twospectral components above $\sim1$ keV: a blackbody-like one with$kT^\infty=138\pm13$ eV and emitting radius $31_{-16}^{+8}$ m, and a power lawwith photon index $\Gamma=1.4_{-0.4}^{+0.5}$. The power-law 2--8\,keV flux,$(2.5_{-0.6}^{+0.7})\times10{-15}$ erg cm$^{-2}$ s$^{-1}$, corresponds to anefficiency of $10^{-3}$, in line with that seen in other pulsars. We alsoreveal a small difference between the $0.1$--$0.3$ keV and $0.3$--$1.2$ keVpulse profiles, as well as some evidence for a modulation above $1.2$ keV.These results show that, notwithstanding its simple spectrum, \eighteen stillhas a non-trivial thermal surface distribution and features non-thermalemission as seen in other pulsars with higher spin-down power.

monthly notices of the royal astronomical society

Two decades of X-ray observations of the isolated neutron star RX  J1856.5-3754: detection of thermal and non-thermal hard X-rays and refined  spin-down measurement