General History of X-Ray Polarimetry in Astrophysics

X-Ray Polarimetry and IXPE mission

“…The equivalent of Einstein was IXPE launched 43 years later! [1] The third step is still to come. How could this occur?…”

“…After the development and characterization of GPD, this device was proposed as part of multi-instrument missions, such as XEUS, IXO and NHXM or to missions dedicated to polarimetry proposed to ASI (POLARIX), ESA (mini-XIPE, XIPE), CAS (HXMT), NASA (IXPE). After various complications, described in Costa2022 [1], IXPE, proposed in 2014 for the second time as a Small Explorer Mission (SMEX), was approved in 2017 and launched in 2021 in an equatorial Low Earth Orbit [11]. As a SMEX IXPE (Figure 5) is a PI mission based on an agreement of NASA and ASI.…”

Scattering Polarimetry in the Hard X-ray Range

“…Results of the Imaging Polarimetry Explorer eventually demonstrated, after 60 years of predictions, that X-ray polarimetry can be a powerful diagnostic for most classes of sources in the domain of High Energy Astrophysics. A short history of this subject can be found in [1]. The breakthrough performance of IXPE is due to a detector exploiting the photoelectric process.…”