NRAO/Socorro Colloquium Series
Joanna Rankin
University of Vermont
Synchronous X-ray and Radio Mode Changing in Pulsar B0943+10: Evidence for a Rapid Global Transformation of the Magnetosphere
Pulsars are remarkable sources, capable of producing EM emission
from low-frequency radio waves up to high-energy gamma-rays—and from sites
close to the neutron-star surface out to the edges of the magnetosphere. Some
pulsars also exhibit several stable "modal" states with fascinating modulation
properties and in some cases even different spindown torques. B0943+10 has
two such radio modes, one with a carousel of bright accurately drifting subpulses
and another with weak chaotic pulses. Correlated mode changes in the radiation
at different wavelengths are then key to understanding the physical connections
and mechanisms of the emission regions. Through simultaneous observations
with the GMRT, LOFAR, and XMM-Newton observatories, we have detected
synchronous switching in the radio and X-ray emission properties of B0943+10.
When the pulsar is in its radio "bright" mode, the X-rays are unpulsed and have
a non-thermal spectrum. Conversely, when the pulsar is in a radio "quiet" mode,
the X-ray luminosity more than doubles and a 100%-pulsed thermal component
is observed along with the non-thermal radiation. This indicates rapid, global
changes in magnetospheric conditions, which challenge all proposed pulsar
emission theories.
April 26,2013
11:00 am
Array Operations Center Auditorium
All NRAO employees are invited to attend via video, available in Charlottesville Room 230, Green Bank Room 137 and Tucson N525.
Local Host: Tim Hankins
