A Strong Upper Limit on the Pulsed Radio Luminosity of the Compact Object 1RXS J141256.0+792204

TL;DR

This study searched for radio pulsations from the compact object 1RXS J141256.0+792204 using high-resolution radio observations but found no signals, setting strict upper limits on its pulsed radio luminosity and questioning its classification as a nearby radio pulsar.

Contribution

The paper provides the first sensitive radio pulsation search for 1RXS J141256.0+792204 and establishes upper limits on its radio luminosity, challenging its identification as a nearby pulsar.

Findings

No radio pulsations detected at 385 and 1380 MHz.

Set upper limits on pulsed radio luminosity: ~0.3 and 0.03 mJy kpc^2.

Questions the classification of the source as a nearby radio pulsar.

Abstract

The ROSAT X-ray source 1RXS J141256.0+792204 has recently been identified as a likely compact object whose properties suggest it could be a very nearby radio millisecond pulsar at d = 80 - 260pc. We investigated this hypothesis by searching for radio pulsations using the Westerbork Synthesis Radio Telescope. We observed 1RXS J141256.0+792204 at 385 and 1380MHz, recording at high time and frequency resolution in order to maintain sensitivity to millisecond pulsations. These data were searched both for dispersed single pulses and using Fourier techniques sensitive to constant and orbitally modulated periodicities. No radio pulsations were detected in these observations, resulting in pulsed radio luminosity limits of L_400 ~ 0.3 (d/250pc)^2 mJy kpc^2 and L_1400 ~ 0.03 (d/250pc)^2 mJy kpc^2 at 400 and 1400MHz respectively. The lack of detectable radio pulsations from 1RXS J141256.0+792204 brings into question its identification as a nearby radio pulsar, though, because the pulsar could be beamed away from us, this hypothesis cannot be strictly ruled out.