Multi-wavelength polarimetry of fast transients

In the context of pulsar studies we have developed a tool for pulsar gating at radio and gamma-ray energies, in order to disentangle the pulsar signal from that of its pulsar wind nebula (PWN), using the technique of the subtraction of the pulsed component. In the case of the future Imaging X-ray Polarimetry Explorer (IXPE), which will be launched in 2021 and will be able to perform spectral-polarimetry together with spectral timing, the same approach can be applied to obtain phase-resolved polarimetry for the pulsar-PWN systems (one of its key science objectives) where the instrument resolution does not easily allow the separation of the two sources.In parallel, we are developing a tool to search for pulsars and fast radio bursts (FRBs), with a technique alternative to the Fourier transform (FT), which uses the Karhunen-Loève transform (KLT). The KLT is a mathematical algorithm which has not been fully explored yet, due to its high computational demand, but which is potentially more powerful than the FT when applied to a generic signal buried in noise. The same approach can be applied to the search of fast transients of yet unknown nature, or for the search of the same transients, at other wavelengths than radio, if enough statistics is available.The combination of these tools provides the starting point for a pipeline for the detection of new fast transients and their time-resolved and polarimetric studies. We present the application of the tools to the multi-wavelength analysis of real and simulated data of a sample of pulsars and their PWNe, for which we determine the spectral timing and polarimetry properties from radio to gamma-rays and discuss how the new generation of telescopes can help constrain the geometrical structure and emission mechanisms of fast transients.