DERIVING THE GLOBAL STRUCTURE OF THE GALACTIC MAGNETIC FIELD FROM FARADAY ROTATION MEASURES OF EXTRAGALACTIC SOURCES

By Maxim Pshirkov, P. Tinyakov, P. Kronberg, K. Newton-McGee. 2011

243 citations recorded by the source corpus.

We made use of the two latest sets of rotation measures (RMs) of extragalactic radio sources, namely the NRAO VLA Sky Survey rotation measures catalog and a compilation by Kronberg and Newton-McGee, to infer the global structure of the Galactic magnetic field (GMF). We have checked that these two data sets are mutually consistent. Given the existence of clear patterns in the all-sky RM distributions we considered GMF models consisting of two components: disk (spiral or ring) and halo. The parameters of these components were determined by fitting different model field geometries to the observed RMs. We found that the model consisting of a symmetric (with respect to the Galactic plane) spiral disk and antisymmetric halo fits the data best and reproduces the observed distribution of RMs over the sky very well. We confirm that ring disk models are disfavored. Our results favor small pitch angles around ∼ − 5° and an increased vertical scale of electron distribution, in agreement with some recent studies. Based on our fits, we select two benchmark models suitable for studies of cosmic ray propagation, including cosmic rays at ultrahigh energies.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/6a1a10236a6554cdb92d30f77944123b45ca6e6c

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In Astronomy and Astrophysics

1. A. Strong
2. A. Banday
3. E. Orlando
4. H. Eriksen
5. G. Farrar
6. R. Jansson
7. F. Hansen
8. P. Lilje

In Nuclear and High Energy Physics

1. A. Strong
2. E. Orlando
3. Tim Huege
4. R. Durrer
5. Andrii Y. Neronov
6. G. Farrar
7. R. Jansson
8. Angela V. Olinto

Citations in the corpus

• Galactic synchrotron emission with cosmic ray propagation models (2013, methodology): “Pshirkov et al. (2011) selected two benchmark models, fitting different B-fields to the observed RMs. Jansson & Farrar (2012b), instead, derived their best-fitting model including also a striated component.”
• Cosmic-ray propagation with DRAGON2: I. numerical solver and astrophysical ingredients (2016, methodology): “The best-fit parameters, derived from a wider set of Faraday Rotation measurements, is however different as reported in table 3 of [98] for both the ASS and BSS configurations.”
• Cosmological Magnetic Fields: Their Generation, Evolution and Observation (2013, background): “However, our knowledge of the Galactic magnetic field is rather limited (Han and Qiao 1994; Brown et al 2007; Pshirkov et al 2011; Jansson and Farrar 2012a,b; Oppermann et al 2012) and there still are large uncertainties in Galactic field models.”
• A NEW MODEL OF THE GALACTIC MAGNETIC FIELD (2012, unknown): “…(2008) and Sun & Reich (2010) modeling the disk and halo GMF and constraining the model with multi-wavelength synchrotron and rotation measure data; Pshirkov et al. (2011) comparing models in the literature (and proposing two benchmark models) using full-sky rotation measure data, some of which…”
• Revisiting the SN1987A gamma-ray limit on ultralight axion-like particles (2014, methodology): “including effects of proton degeneracy and of the reduction of the proton mass in the dense stellar medium; (c) we accurately characterize the ALP–photon conversions in the Milky Way, solving the oscillation equations using sophisticated models of the Galactic magnetic field [54, 55].”
• Open Questions in Cosmic-Ray Research at Ultrahigh Energies (2019, background): “Yuksel et al. (2012) have argued that at energies of ∼ 100 EeV, a putative correlation of events observed by Auger with Cen A (Aab et al., 2015d) would imply an EGMF with strength B & 20 nG, assuming a pure proton composition and the GMF model from Pshirkov et al. (2011).”
• CRPropa 3—a public astrophysical simulation framework for propagating extraterrestrial ultra-high energy particles (2016, methodology): “[16] are implemented and can be used as examples for other models.”
• An Indication of Anisotropy in Arrival Directions of Ultra-high-energy Cosmic Rays through Comparison to the Flux Pattern of Extragalactic Gamma-Ray Sources (2018, methodology): “The sky maps used in this analysis are derived without incorporating any effects of the extragalactic or Galactic magnetic fields and winds (e.g., Pshirkov et al. 2011; Jansson & Farrar 2012; Biermann et al. 2015).”
• An improved map of the Galactic Faraday sky (2011, background): “…field with rotation measures of extragalactic radio sources are those by Brown & Taylor (2001), Mao et al. (2010), Kronberg & Newton-McGee (2011), Pshirkov et al. (2011), and Brown et al. (2003b, 2007), Nota & Katgert (2010), and Van Eck et al. (2011), who supplemented extragalactic RMs with…”
• THE GALACTIC MAGNETIC FIELD (2012, methodology): “…χ2 per degree of freedom of 1.096 for the 6605 observables (pixels of RM, Q and U) while the fit is much worse for other recent models in the literature, with χ2dof of 2.663 & 4.971 for Pshirkov et al. (2011) BSS & ASS respectively and 1.672 for Sun et al. (2008), with their 2010 parameter update.”
• Planck intermediate results. XIX. An overview of the polarized thermal emission from Galactic dust (2014, background): “…as a result of both progress in the quality (sensitivity and resolution) of radio observations and extensive modelling efforts (e.g., Sun et al. 2008; Sun & Reich 2010; Ruiz-Granados et al. 2010; Jaffe et al. 2010, 2011; Pshirkov et al. 2011; Fauvet et al. 2012, 2013; Jansson & Farrar 2012a,b).”