Alaa Ibrahim and coworkers discovered the first transient magnetar,
XTE J1810-197, serendipitously during an observation of another
magnetar nearby.
Magnetars, a rare class of extremely magnetic neutron stars, are
thought to be born with ultrahigh magnetic fields. The transient nature
this magnetar supports the theory that these objects may at first be too
dim to see, but eventually brighten as the spinning star slows down
and releases energy.
Studying the history of XTE J1810-197 has involved several high
energy observatories. Chandra was used to accurately pinpoint the location
of the new object. Archival XTE data revealed that XTE J1810-197 brightened
by a factor of about 100 around January 2003.
Finally, the archives of the earlier international missions ROSAT and ASCA
were mined, revealing the source as a dim, isolated neutron star as early
early as 1990. This exciting new development in neutron star evolution was
presented at the Winter 2004 AAS Meeting in Atlantia,Georgia.
See this story on the Goddard Homepage.