Spin Period Changes of Isolated Neutron Stars

We propose XMMNewton observations of two pulsating isolated neutron stars,INSs, for which no precise spin period and no period derivative are determinedyet. A monitoring program will allow to derive these fundamental parameterswith high accuracy and perform detailed pulse phase spectroscopy and pulseprofile modelling. The XMMNewton observations of the pulsars RXJ0420.05022,22.69 s, and RXJ0806.44123, 11.37 s, will complement the results obtained forthe only known other two pulsating INSs RXJ0720.43125 and RBS1223 and arecrucial for our knowledge of magnetic field and spin evolution of INSs and forour understanding of the whole class of INSs including soft gamma repeatersand anomalous Xray pulsars. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]