Planck intermediate results. XLII. Large-scale Galactic magnetic fields
Abstract
Recent models for the large-scale Galactic magnetic fields in the literature have been largely constrained by synchrotron emission and Faraday rotation measures. We use three different but representative models to compare their predicted polarized synchrotron and dust emission with that measured by the Planck satellite. We first update these models to match the Planck synchrotron products using a common model for the cosmic-ray leptons. We discuss the impact on this analysis of the ongoing problems of component separation in the Planck microwave bands and of the uncertain cosmic-ray spectrum. In particular, the inferred degree of ordering in the magnetic fields is sensitive to these systematic uncertainties, and we further show the importance of considering the expected variations in the observables in addition to their mean morphology. We then compare the resulting simulated emission to the observed dust polarization and find that the dust predictions do not match the morphology in the Planck data but underpredict the dust polarization away from the plane. We modify one of the models to roughly match both observables at high latitudes by increasing the field ordering in the thin disc near the observer. Though this specific analysis is dependent on the component separation issues, we present the improved model as a proof of concept for how these studies can be advanced in future using complementary information from ongoing and planned observational projects.
Cite
@article{arxiv.1601.00546,
title = {Planck intermediate results. XLII. Large-scale Galactic magnetic fields},
author = {Planck Collaboration and R. Adam and P. A. R. Ade and M. I. R. Alves and M. Ashdown and J. Aumont and C. Baccigalupi and A. J. Banday and R. B. Barreiro and N. Bartolo and E. Battaner and K. Benabed and A. Benoit-Lévy and J. -P. Bernard and M. Bersanelli and P. Bielewicz and L. Bonavera and J. R. Bond and J. Borrill and F. R. Bouchet and F. Boulanger and M. Bucher and C. Burigana and R. C. Butler and E. Calabrese and J. -F. Cardoso and A. Catalano and H. C. Chiang and P. R. Christensen and L. P. L. Colombo and C. Combet and F. Couchot and B. P. Crill and A. Curto and F. Cuttaia and L. Danese and R. J. Davis and P. de Bernardis and A. de Rosa and G. de Zotti and J. Delabrouille and C. Dickinson and J. M. Diego and K. Dolag and O. Doré and A. Ducout and X. Dupac and F. Elsner and T. A. Enßlin and H. K. Eriksen and K. Ferrière and F. Finelli and O. Forni and M. Frailis and A. A. Fraisse and E. Franceschi and S. Galeotta and K. Ganga and T. Ghosh and M. Giard and E. Gjerløw and J. González-Nuevo and K. M. Górski and A. Gregorio and A. Gruppuso and J. E. Gudmundsson and F. K. Hansen and D. L. Harrison and C. Hernández-Monteagudo and D. Herranz and S. R. Hildebrandt and M. Hobson and A. Hornstrup and G. Hurier and A. H. Jaffe and T. R. Jaffe and W. C. Jones and M. Juvela and E. Keihänen and R. Keskitalo and T. S. Kisner and J. Knoche and M. Kunz and H. Kurki-Suonio and J. -M. Lamarre and A. Lasenby and M. Lattanzi and C. R. Lawrence and J. P. Leahy and R. Leonardi and F. Levrier and M. Liguori and P. B. Lilje and M. Linden-Vørnle and M. López-Caniego and P. M. Lubin and J. F. Macías-Pérez and G. Maggio and D. Maino and N. Mandolesi and A. Mangilli and M. Maris and P. G. Martin and E. Martínez-González and S. Masi and S. Matarrese and A. Melchiorri and A. Mennella and M. Migliaccio and M. -A. Miville-Deschênes and A. Moneti and L. Montier and G. Morgante and D. Munshi and J. A. Murphy and P. Naselsky and F. Nati and P. Natoli and H. U. Nørgaard-Nielsen and N. Oppermann and E. Orlando and L. Pagano and F. Pajot and R. Paladini and D. Paoletti and F. Pasian and L. Perotto and V. Pettorino and F. Piacentini and M. Piat and E. Pierpaoli and S. Plaszczynski and E. Pointecouteau and G. Polenta and N. Ponthieu and G. W. Pratt and S. Prunet and J. -L. Puget and J. P. Rachen and M. Reinecke and M. Remazeilles and C. Renault and A. Renzi and I. Ristorcelli and G. Rocha and M. Rossetti and G. Roudier and J. A. Rubiño-Martín and B. Rusholme and M. Sandri and D. Santos and M. Savelainen and D. Scott and L. D. Spencer and V. Stolyarov and R. Stompor and A. W. Strong and R. Sudiwala and R. Sunyaev and A. -S. Suur-Uski and J. -F. Sygnet and J. A. Tauber and L. Terenzi and L. Toffolatti and M. Tomasi and M. Tristram and M. Tucci and L. Valenziano and J. Valiviita and F. Van Tent and P. Vielva and F. Villa and L. A. Wade and B. D. Wandelt and I. K. Wehus and D. Yvon and A. Zacchei and A. Zonca},
journal= {arXiv preprint arXiv:1601.00546},
year = {2016}
}
Comments
31 pages, 16 figures, updated to match accepted A&A version