Discovery of Polarized X-Ray Emission from the Accreting Millisecond Pulsar SRGA J144459.2-604207
Alessandro Papitto, Alessandro Di Marco, Juri Poutanen, Tuomo Salmi, Giulia Illiano, Fabio La Monaca, Filippo Ambrosino, Anna Bobrikova, Maria Cristina Baglio, Caterina Ballocco, Luciano Burderi, Sergio Campana, Francesco Coti Zelati, Tiziana Di Salvo, Riccardo La Placa, Vladislav Loktev, Sinan Long, Christian Malacaria, Arianna Miraval Zanon, Mason Ng, Maura Pilia, Andrea Sanna, Luigi Stella, Tod Strohmayer, Silvia Zane
arXiv:2408.00608v1 Announce Type: new
Abstract: We report on the discovery of polarized X-ray emission from an accreting millisecond pulsar. During a 10-day-long coverage of the February 2024 outburst of SRGA J144459.2-604207, the Imaging X-ray Polarimetry Explorer (IXPE) detected an average polarization degree of the 2-8 keV emission of 2.3% +/- 0.4% at an angle of 59{deg} +/- 6{deg} (East of North; uncertainties quoted at the 1${sigma}$ confidence level). The polarized signal shows a significant energy dependence with a degree of 4.0% +/- 0.5% between 3 and 6 keV and arXiv:2408.00608v1 Announce Type: new
Abstract: We report on the discovery of polarized X-ray emission from an accreting millisecond pulsar. During a 10-day-long coverage of the February 2024 outburst of SRGA J144459.2-604207, the Imaging X-ray Polarimetry Explorer (IXPE) detected an average polarization degree of the 2-8 keV emission of 2.3% +/- 0.4% at an angle of 59{deg} +/- 6{deg} (East of North; uncertainties quoted at the 1${sigma}$ confidence level). The polarized signal shows a significant energy dependence with a degree of 4.0% +/- 0.5% between 3 and 6 keV and