Naslov
Multi-tracer analysis of straight depolarisation canals in the surroundings of the 3C 196 field

Autori
Turić, Luka ; Jelić, Vibor ; Jaspers, Rutger ; Haverkorn, Marijke ; Bracco, Andrea ; Erceg, Ana ; Ceraj, Lana ; van Eck, Cameron ; Zaroubi, Saleem

Izvornik
Astronomy & astrophysics (Berlin) (0004-6361) 654 (2021); A5, 13

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
ISM: general ; ISM: magnetic fields ; ISM: structure ; radio continuum: ISM ; techniques: interferometric ; techniques: polarimetric

Sažetak
Context. Faraday tomography of a field centred on the extragalactic point source 3C 196 with the LOw Frequency ARray (LOFAR) revealed an intertwined structure of diffuse polarised emission with straight depolarisation canals and tracers of the magnetised and multi-phase interstellar medium (ISM), such as dust and line emission from atomic hydrogen (HI). Aims: This study aims at extending the multi-tracer analysis of LOFAR data to three additional fields in the surroundings of the 3C 196 field. For the first time, we study the three- dimensional structure of the LOFAR emission by determining the distance to the depolarisation canals. Methods: We used the rolling Hough transform to compare the orientation of the depolarisation canals with that of the filamentary structure seen in HI, and based on starlight and dust polarisation data, with that of the plane-of- the-sky magnetic field. Stellar parallaxes from Gaia complemented the starlight polarisation with the corresponding distances. Results: Faraday tomography of the three fields shows a rich network of diffuse polarised emission at Faraday depths between − 10 and + 15 rad m−2. A complex system of straight depolarisation canals resembles that of the 3C 196 field. The depolarisation canals align both with the HI filaments and with the magnetic field probed by dust. The observed alignment suggests that an ordered magnetic field organises the multiphase ISM over a large area (~20°). In one field, two groups of stars at distances below and above 200 pc, respectively, show distinct magnetic field orientations. These are both comparable with the orientations of the depolarisation canals in the same field. We conclude that the depolarisation canals likely trace the same change in the magnetic field as probed by the stars, which corresponds to the edge of the Local Bubble.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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