Hard X-ray Polarization observations from celestial objects by the international balloon-borne mission, XL-Calibur

Dr. Hiromitsu TAKAHASHI
Hiroshima University

The hard X-ray polarimeter mission, XL-Calibur, is an international project among Japan, the U.S., and Sweden. The Japanese FFAST mirror is equipped to focus 15-80 keV hard X-ray from celestial sources, and achieves the highest sensitivity. In July 2024, it flew from Sweden to Canada for about 1 week and successfully performed observations of Crab (pulsar-wind nebula) and Cygnus X-1 (black-hole X-ray binary) from the stratosphere 40 km above the ground.
Polarimetry is a powerful observational tool that provides physical quantities (such as magnetic field and geometric structure) independent of imaging, photometry, and spectroscopy. However, the high energy band of X-rays and gamma rays is still unexplored, and polarization observations of soft X-rays of 2-8 keV has just started with the IXPE satellite launched in 2021. It is important to perform broadband polarization observations, and we are promoting the XL-Calibur balloon-borne experiment (PI: H. Krawczynski, WUSTL) to observe 15-80 keV hard X-rays. In this talk, we will report on the progress of the development and data analysis of the XL-Calibur mission and future plans for the Antarctic flight.

Conference Hall (2nd floor/ Research and Administration Building A),　Via Zoom