X-ray Polarization of BL Lacertae in Outburst

Abel L. Peirson, Michela Negro, Ioannis Liodakis +128

We report the first $>99\%$ confidence detection of X-ray polarization in BL Lacertae. During a recent X-ray/$\gamma$-ray outburst, a 287 ksec observation (2022 November 27-30) was tak…