X-Ray Polarization Observations of BL Lacertae
Journal article, 2023

Blazars are a class of jet-dominated active galactic nuclei with a typical double-humped spectral energy distribution. It is of common consensus that the synchrotron emission is responsible for the low frequency peak, while the origin of the high frequency hump is still debated. The analysis of X-rays and their polarization can provide a valuable tool to understand the physical mechanisms responsible for the origin of high-energy emission of blazars. We report the first observations of BL Lacertae (BL Lac) performed with the Imaging X-ray Polarimetry Explorer, from which an upper limit to the polarization degree Π X < 12.6% was found in the 2-8 keV band. We contemporaneously measured the polarization in radio, infrared, and optical wavelengths. Our multiwavelength polarization analysis disfavors a significant contribution of proton-synchrotron radiation to the X-ray emission at these epochs. Instead, it supports a leptonic origin for the X-ray emission in BL Lac.

Active galactic nuclei

X-ray active galactic nuclei

Blazars

Relativistic jets

Spectropolarimetry

Author

Ricardo Middei

Agenzia Spaziale Italiana

Istituto nazionale di astrofisica (INAF)

Georgia Virginia Panopoulou

California Institute of Technology (Caltech)

et al.

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 942 10M

Subject Categories

Astronomy, Astrophysics and Cosmology

DOI

10.3847/2041-8213/aca281

More information

Latest update

4/5/2024 8