Flux density measurements of GPS candidate pulsars at 610 MHz using interferometric imaging technique

TL;DR

This study uses interferometric imaging at 610 MHz with GMRT to measure flux densities of GPS candidate pulsars, confirming spectral features and demonstrating the technique's effectiveness in scattering conditions.

Contribution

First application of interferometric imaging at 610 MHz to measure fluxes of GPS candidate pulsars, including those affected by strong scatter-broadening.

Findings

Confirmed GPS feature in PSR B1823−13 spectrum.

Demonstrated interferometric imaging's effectiveness in scattering environments.

Provided low-frequency flux measurements for high DM pulsars.

Abstract

We conducted radio interferometric observations of six pulsars at 610 MHz using the Giant Metrewave Radio Telescope (GMRT). All these objects were claimed or suspected to be the gigahertz-peaked spectra (GPS) pulsars. For a half of the sources in our sample the interferometric imaging provides the only means to estimate their flux at 610 MHz due to a strong pulse scatter-broadening. In our case, these pulsars have very high dispersion measure values and we present their spectra containing for the first time low-frequency measurements. The remaining three pulsars were observed at low frequencies using the conventional pulsar flux measurement method. The interferometric imaging technique allowed us to re-examine their fluxes at 610 MHz. We were able to confirm the GPS feature in the PSR B1823$-$13 spectrum and select a GPS candidate pulsar. These results clearly demonstrate that the interferometric imaging technique can be successfully applied to estimate flux density of pulsars even in the presence of strong scattering.