Speaker
amruta jaodand
(ASTRON- Netherlands Institute for Radio Astronomy)
Description
Recently, Bogdanov $\&$ Halpern (2015) identified the unassociated Fermi gamma-ray source $3$FGL~J$1544.6-1125$ as only the $4$th known "transitional millisecond pulsar" (tMSP), a claim further bolstered by follow-up observations by Bogdanov (2015). The tMSPs are a newly discovered class of binary systems that transition between states as a radio millisecond pulsar and a low-mass X-ray binary (LMXB). In the LMXB state tMSPs show X-ray variability over ~$10-100$s, switching between 'high' and 'low' luminosity modes, as well as infrequent 'flares'. In the high mode, coherent X-ray pulsations are seen, indicating channeled accretion onto the neutron star surface despite the very low accretion rate, and offering the potential to study very low-level accretion onto neutron stars. A coordinated radio/X-ray campaign undertaken for PSR J$1023+0038$ showed that this tMSP is much brighter in radio than expected, and with rapidly variable and flat spectrum continuum emission most likely associated with compact, self-absorbed jet (Deller et al. 2015). This strongly hints at radiatively inefficient accretion flow where majority of accretion energy goes into an outflow. $3$FGL J$1544.6-1125$ is currently the only other system in the right state for detailed observations to confirm whether efficient jet formation is common to all tMSPs, and would add a $4$th important data point to the newly hypothesized radio/X-ray luminosity relationship for tMSPs. We have therefore observed it with VLA four times over the period of several weeks. Preliminary results indeed show a behaviour similar to J$1023$, further strengthening the case for $3$FGL J$1544$ being a tMSP. I would be presenting results from this first ever observational campaign to detect the source in radio.
Primary author
amruta jaodand
(ASTRON- Netherlands Institute for Radio Astronomy)
Co-authors
Adam Deller
Alessandro Patruno
(L)
Ms
Anne Archibald
(Netherlands Institute for Radio Astronomy)
Mr
Cees Bassa
(Manchester, University of (Jodrell Bank))
Mr
James Miller-Jones
(Curtin University of Technology)
Mr
Jason Hessels
(Netherlands Institute for Radio Astronomy)
Mr
Javier Moldon
(Netherlands Institute for Radio Astronomy)
Rudy Wijnands
(University of Amsterdam)
Mr
Slavko Bogdanov
(Columbia University)
