X-Ray Properties of PSR J1811-1925 by NuSTAR

We analyzed the spectral properties and pulse profile of PSR J1811-1925, a pulsar located in the center of composite supernova remnant (SNR) G11.2-0.3, by using high timing resolution archival data from the Nuclear Spectroscopic Telescope Array Mission (NuSTAR). Analysis of archival Chandra data over different regions rules out the SNR shell as the site of the hard X-ray emission while spectral analysis indicates that the NuSTAR photons originate in the pulsar and its nebula. The pulse profile exhibits a broad single peak up to 35 keV. The jointed spectrum by combining NuSTAR and Chandra can be well fitted by a power-law model with a photon index of Gamma = 1.58 +/- 0.04. The integrated flux of jointed spectrum over 1-10 keV is 3.36 x 10(-12) erg cm(-2) s(-1). The spectrum of pulsar having photon index Gamma = 1.33 +/- 0.06 and a 1-10 keV flux of 0.91 x 10(-12) erg cm(-2) s(-1). We also performed the phase-resolved spectral analysis by splitting the whole pulse-on phase into five phase bins. The photon indices of the bins are all around 1.4, indicating that the photon index does not evolve with the phase.