The continued spectral evolution of the neutron star RX J0720.4-3125
  We observed the isolated neutron star RX J720.4-3125 with Chandra's Low Energy Transmission Grating Spectrometer, following the XMM-Newton discovery of long term spectral evolution of this source. The new observation shows that the spectrum of RX J720.4-3125 has continued to change in the course of 5 months. It has remained hard, similar to the last XMM-Newton observation, but the strong depression observed with XMM-Newton at long wavelengths has disappeared. Contrary to the XMM-Newton observations, the new Chandra observation shows that the flux increase at short wavelengths and the decrease at long wavelengths do not necessarily occur simultaneously. 
Jacco Vink (1), Cor de Vries (1), Mariano Mendez (1), Frank Verbunt   (2) ((1) SRON, Utrecht, The Netherlands, (2) Astronomi...