The IXPE and multifrequency polarimetric view of the extreme blazars 1ES 1101-232 and RGB J0710+591
/ Authors
F. Tavecchio, Dawoon E. Kim, G. Emery, I. Liodakis, I. Agudo, P. Coppi, G. Tagliaferri, L. D. Gesu, T. Sbarrato, Lucia Ballo
and 46 more authors
A. Sciaccaluga, S. Ehlert, G. Bonnoli, F. Aceituno, C. Casadio, V. Casanova, I. Donnarumma, J. Escudero, D. Morcuende, J. Otero-Santos, A. Sota, V. Piirola, P. M. Kouch, E. Lindfors, Kari Nilsson, I. Myserlis, M. Gurwell, G. Keating, Ramprasad Rao, E. Angelakis, A. Kraus, R. Imazawa, M. Sasada, Yasushi Fukazawa, K. Kawabata, M. Uemura, T. Mizuno, T. Nakaoka, Sumie Tochihara, Takahiro Akai, H. Akitaya, R. Bachev, A. Strigachev, P. Benke, L. Debbrecht, J. Eich, F. Eppel, A. Gokus, S. Hammerich, J. Hessdorfer, M. Kadler, Sanghyun Kim, D. Kirchner, G. Paraschos, F. Rosch, W. Schulga
/ Abstract
Multiwavelength polarimetry offers a powerful tool to probe magnetic field and flow geometries in the relativistic jets of blazars. Sources with synchrotron emission that spans a broad frequency range, from radio to X-rays, such as High Synchrotron Peak (HSP) type BL Lac objects, are particularly interesting. Previous measurements including radio, optical, and X-ray data show a clear trend, with the degree of polarization increasing with frequency. Here we report radio, optical, and X-ray observations (Swift, Nustar, and IXPE) of 1ES 1101-232 and RGB J0710+591, two blazars belonging to the puzzling subclass of extreme BL Lacs (EHBL). For 1ES 1101-232, we find a strong frequency dependence of the degree of polarization, with a ratio Π_X/Π_O≃ 5.2. For RGB J0710+591, IXPE derives a 1σ upper limit Π_X<11.6%, comparable to the measured optical degree of polarization (average Π_O∼ 12%). We discuss the results in the framework of current interpretations and, in particular, we report an improved version of the stratified shock model that reproduces the observed data of both sources.
Journal: Astronomy & Astrophysics