Search: onr:"swepub:oai:DiVA.org:su-207840" >
Degree-scale galact...
Degree-scale galactic radio emission at 122 MHz around the North Celestial Pole with LOFAR-AARTFAAC
- Article/chapterEnglish2022
Publisher, publication year, extent ...
-
2022-06-24
-
EDP Sciences,2022
-
printrdacarrier
Numbers
-
LIBRIS-ID:oai:DiVA.org:su-207840
-
https://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-207840URI
-
https://doi.org/10.1051/0004-6361/202142939DOI
Supplementary language notes
-
Language:English
-
Summary in:English
Part of subdatabase
Classification
-
Subject category:ref swepub-contenttype
-
Subject category:art swepub-publicationtype
Notes
-
Aims. Contamination from bright diffuse Galactic thermal and non-thermal radio emission poses crucial challenges in experiments aiming to measure the 21-cm signal of neutral hydrogen from the cosmic dawn (CD) and Epoch of Reionisation (EoR). If not included in calibration, this diffuse emission can severely impact the analysis and signal extraction in 21-cm experiments. We examine large-scale diffuse Galactic emission at 122 MHz around the North Celestial Pole, using the Amsterdam-ASTRON Radio Transient Facility and Analysis Centre (AARTFAAC-) High Band Antenna (HBA) system.Methods. In this pilot project, we present the first-ever wide-field image produced with a single sub-band of the data recorded with the AARTFAAC-HBA system. We demonstrate two methods, multi-scale CLEAN and shapelet decomposition, to model the diffuse emission revealed in the image. We used angular power spectrum metrics to quantify different components of the emission and compared the performance of the two diffuse structure modelling approaches.Results. We observed that the point sources dominate the angular power spectrum (ℓ(ℓ + 1)Cℓ/2π≡Δ2(ℓ)) of the emission in the field on scales of ℓ ≳ 60 (≲3 degree). The angular power spectrum after subtraction of compact sources is flat within the 20 ≲ ℓ ≲ 200 range, suggesting that the residual power is dominated by the diffuse emission on scales of ℓ ≲ 200. The residual diffuse emission has a brightness temperature variance of Δℓ=1802 = (145.64 ± 13.61) K2 at 122 MHz on angular scales of 1 degree, and it is consistent with a power law following Cℓ ∝ ℓ−2.0 in the 20 ≲ ℓ ≲ 200 range. We also find that, in the current set-up, multi-scale CLEAN is suitable to model the compact and diffuse structures on a wide range of angular scales, whereas the shapelet decomposition method better models the large scales, which are of the order of a few degrees and wider.
Subject headings and genre
Added entries (persons, corporate bodies, meetings, titles ...)
-
Koopmans, L. V. E.
(author)
-
Offringa, A. R.
(author)
-
Gan, H.
(author)
-
Ghara, R.
(author)
-
Giri, S. K.
(author)
-
Kuiack, M.
(author)
-
Mertens, F. G.
(author)
-
Mevius, M.
(author)
-
Mondal, RajeshStockholms universitet,Institutionen för astronomi,Oskar Klein-centrum för kosmopartikelfysik (OKC)(Swepub:su)ramo8095
(author)
-
Pandey, V. N.
(author)
-
Shulevski, A.
(author)
-
Wijers, R. A. M. J.
(author)
-
Yatawatta, S.
(author)
-
Stockholms universitetInstitutionen för astronomi
(creator_code:org_t)
Related titles
-
In:Astronomy and Astrophysics: EDP Sciences6620004-63611432-0746
Internet link
Find in a library
To the university's database
- By the author/editor
-
Gehlot, B. K.
-
Koopmans, L. V. ...
-
Offringa, A. R.
-
Gan, H.
-
Ghara, R.
-
Giri, S. K.
-
show more...
-
Kuiack, M.
-
Mertens, F. G.
-
Mevius, M.
-
Mondal, Rajesh
-
Pandey, V. N.
-
Shulevski, A.
-
Wijers, R. A. M. ...
-
Yatawatta, S.
-
show less...
- About the subject
-
- NATURAL SCIENCES
-
NATURAL SCIENCES
-
and Physical Science ...
-
and Astronomy Astrop ...
- Articles in the publication
-
Astronomy and As ...
- By the university
-
Stockholm University