Monitoring the Decay of XTE J1810-197

TWO DAYS FOLLOWING REPORTS OF AN OUTBURST FROM THE TRANSIENT ANOMALOUS X-RAY PULSAR (AXP) XTE J1810-197 WE OBTAINED A NUSTAR DDT OBSERVATION TO CHARACTERIZE ITS OUTBURST PROPERTIES. THUS 15 YEARS AFTER THE 2003 DISCOVERY OF THIS THE FIRST KNOWN TRANSIENT AND RADIO AXP IT IS POSSIBLE TO STUDY THE ORIGIN AND DECAY OF MAGNETAR EMISSION IN EXQUISITE DETAIL FROM THE BEGINNING OF THE OUTBURST IN A UNIQUELY ACCESSIBLE SOURCE. WE PROPOSE HERE TO CONTINUE OUR NICER MONITORING OF XTE J1810-197 TO FOLLOW ITS X-RAY SPECTRAL AND PULSED EVOLUTION MEASURING ITS SURFACE THERMAL HOT SPOTS AND MAGNETIC FIELD CONFIGURATION TO COMPARE WITH THE ORIGINAL OUTBURST AT A SIMILAR EPOCHS.