Infrared Observations of The Millisecond Pulsar Binary J1023+0038: Evidence for Short-Term Nature of Its Interacting Phase in 2000--2001

TL;DR

This study used multi-band infrared observations to demonstrate that the accretion disk in the millisecond pulsar binary J1023+0038 was present only during a short-term phase around 2000--2001, with no evidence of the disk in later observations.

Contribution

It provides direct infrared evidence that the accretion disk in J1023+0038 was transient, lasting at most 2.5 years, highlighting the short-term nature of its interacting phase.

Findings

Infrared fluxes match 2000 data, indicating no disk in 2000--2001.

No detection of the source in WISE and Herschel data, constraining dust mass.

The accretion disk's existence was limited to a brief period, not sustained over years.

Abstract

We report our multi-band infrared (IR) imaging of the transitional millisecond pulsar system J1023+0038, a rare pulsar binary known to have an accretion disk in 2000--2001. The observations were carried out with ground-based and space telescopes from near-IR to far-IR wavelengths. We detected the source in near-IR JH bands and Spitzer 3.6 and 4.5 $\mu$m mid-IR channels. Combined with the previously-reported optical spectrum of the source, the IR emission is found to arise from the companion star, with no excess emission detected in the wavelength range. Because our near-IR fluxes are nearly equal to those obtained by the 2MASS all-sky survey in 2000 Feb., the result indicates that the binary did not contain the accretion disk at the time, whose existence would have raised the near-IR fluxes to 2-times larger values. Our observations have thus established the short-term nature of the interacting phase seen in 2000--2001: the accretion disk at most existed for 2.5 yrs. The binary was not detected by the WISE all-sky survey carried out in 2010 at its 12 and 22 $\mu$m bands and our Herschel far-IR imaging at 70 and 160 $\mu$m. Depending on the assumed properties of the dust, the resulting flux upper limits provide a constraint of <3x10^{22}--3x10^{25} g on the mass of the dust grains that possibly exist as the remnant of the previously-seen accretion disk.