LOFAR Deep Fields: Probing faint Galactic polarised emission in ELAIS-N1

• DOI: 10.48550/arxiv.2303.13152
• Publication Date: 2023-01-01
• Authors: Iva Šnidarić; Vibor Jelić; M. Mevius; M. A. Brentjens; A. Erceg; T. W. Shimwell; Sara Piras; C. Horellou; J. Sabater; P. N. Best; A. Bracco; L. Ceraj; M. Haverkorn; S. P. O’Sullivan; Luka Turić; V. Vacca
• Keywords: LOFAR

We present the first deep polarimetric study of Galactic synchrotron emission at low radio frequencies. Our is based on 21 observations European Large Area Infrared Space Observatory Survey-North 1 (ELAIS-N1) field using Low-Frequency Array (LOFAR) frequencies from 114.9 to 177.4 MHz. These data are a part LOFAR Two-metre Sky Survey Deep Fields Data Release 1. used very low-resolution ($4.3'$) Stokes QU cubes this release. applied rotation measure (RM) synthesis decompose distribution polarised structures in Faraday depth, and cross-correlation RM align different depth. stacked images about 150 hours ELAIS-N1 produce deepest cube date, tailored studies intervening magneto-ionic interstellar medium. This covers $\sim36~{\rm deg^{2}}$ sky has noise $27~{\rm μJy~PSF^{-1}~RMSF^{-1}}$ intensity. an improvement by factor approximately square root number ($\sim\sqrt{20}$), as expected, compared one single five-to-eight-hour observations. detect faint component diffuse cube, which was not detected previously. Additionally, we verify reliability ionospheric corrections estimated satellite-based total electron content measurements be $~\sim0.05~{\rm rad~m^{-2}}$. also demonstrate that itself can account for relative with respect reference observation.