Multiwavelength Studies of X-ray Binaries

TL;DR

Multiwavelength observations, especially including mid-infrared data from Spitzer, have significantly advanced understanding of X-ray binaries by revealing jet emissions, disk structures, and the effects of obscuration, leading to more comprehensive physical models.

Contribution

This paper emphasizes the importance of coordinated multiwavelength observations, particularly mid-infrared, for studying X-ray binaries and highlights recent gains in understanding their physical properties.

Findings

Mid-infrared observations reveal jet synchrotron emission in neutron stars.

Infrared data penetrate heavily obscured regions in the Galactic plane.

Multiwavelength studies improve constraints on accretion processes.

Abstract

Simultaneous multiwavelength studies of X-ray binaries have been remarkably successful and resulted in improved physical constraints, a new understanding of the dependence of mass accretion rate on X-ray state, as well as insights on the time-dependent relationship between disk structure and mass-transfer rate. I will give some examples of the tremendous gains we have obtained in our understanding of XRBs by using multiwavelength observations. I will end with an appeal that while Spitzer cryogens are still available a special effort be put forth to obtaining coordinated observations including the mid-infrared: Whereas the optical and near-IR originate as superpositions of the secondary star and of accretion processes, the mid-IR crucially detects jet synchrotron emission from NSs that is virtually immeasurable at other wavelengths. A further benefit of Spitzer observations is that mid-infrared wavelengths can easily penetrate regions that are heavily obscured. Many X-ray binaries lie in the Galactic plane and as such are often heavily obscured in the optical by interstellar extinction. The infrared component of the SED, vital to the study of jets and dust, can be provided {\it only} by Spitzer; in the X-rays we currently have an unprecedented six satellites available and in the optical and radio dozens of ground-based facilities to complement the Spitzer observations.