GRB 221009A: IXPE preliminary upper limits of X-ray polarization
ATel #15678; Michela Negro (CRESST/NASA-GSFC/UMBC), Alberto Manfreda (INFN), Nicola Omodei (Stanford University), Fabio Muleri (INAF-IAPS) for the IXPE Collaboration
on 14 Oct 2022; 16:31 UT
Credential Certification: Giovanni Piano (giovanni.piano@inaf.it)
Subjects: X-ray, Gamma-Ray Burst
IXPE performed the first observation of X-ray polarization of a GRB afterglow in the 2-8 keV energy range. IXPE observed GRB 221009A from 2022-10-11T23:34:28UTC to 2022-10-14T00:45:31UTC for an effective exposure of 100 ks.
From a quick-look analysis of the image-, time- and energy- averaged low-level instrument data (prior to pipeline processing at the IXPE SOC), we report:
Polarization degree (PD) < 11.1%
upper limits are derived with 99% C.L.
These results are preliminary. The IXPE Collaboration will report the final results in a forthcoming publication.
The Imaging X-ray Polarimetry Explorer, commonly known as IXPE is a space observatory with three identical telescopes designed to measure the polarization of cosmic X-rays. X-ray polarimetry enabled by IXPE can be performed in energy-, time-, and angle-resolved fashions. The observatory, which was launched on 9 December 2021, is an international collaboration between NASA and the Italian Space Agency (ASI).
