Program: GS-2007A-DD-10

Title:Optical colour of the anomalous X-ray pulsar 1E 1048.1-5937: a second case for magnetars
PI:Zhongxiang Wang
Co-I(s): Victoria Kaspi, Cees Bassa

Abstract

The anomalous X-ray pulsar (AXP) 1E 1048.1-5937 is one of a dozen sources believed to be magnetars---young neutron stars with extremely strong magnetic fields (~10^14 G). On 2007 April 3, a sudden spin-up (glitch) in the AXP was detected in our RXTE X-ray monitoring observations of the source. Our follow-up ESO/VLT DDT optical observations of the source on May 8 found that its optical I band magnitude increased by approximately 1.3 (compared to the previous measurement in 2003). This brightening in the optical provides a great opportunity to obtain a colour for the source, which would only be the second colour measurement in a magnetar. This observation will constrain the physical origin for the still mysterious optical and IR emission in magnetars.

Publications using this program's data