The Low-Frequency Radio Eclipses of the Black Widow Pulsar J1810+1744

Understand

We have observed and analysed the eclipses of the black widow pulsar J1810+1744 at low radio frequencies.

• Using LOw-Frequency ARray (LOFAR) and Westerbork Synthesis Radio Telescope observations between 2011--2015 we have measured variations in flux density, dispersion measure and scattering around eclipses.
• High-time-resolution, simultaneous beamformed and interferometric imaging LOFAR observations show concurrent disappearance of pulsations and total flux from the source during the eclipses, with a $3\sigma$ upper limit of 36 mJy ($<10\%$ of the pulsar's averaged out-of-eclipse flux density).
• The dispersion measure variations are highly asymmetric, suggesting a tail of material swept back due to orbital motion.