The C-Band All-Sky Survey (C-BASS): constraining diffuse Galactic radio emission in the North Celestial Pole region

Autor(es):Mostrar menos -

Dickinson, C. ^{[1, 2]} ; Barr, A. ^[2] ; Chiang, H. C. ^{[3, 4]} ; Copley, C. ^{[5, 6, 7]} ; Grumitt, R. D. P. ^[5] ; Harper, S. E. ^[2] ; Heilgendorff, H. M. ^[4] ; Jew, L. R. P. ^[5] ; Jonas, J. L. ^{[6, 7]} ; Jones, Michael E. ^[5] ; Leahy, J. P. ^[2] ; Leech, J. ^[5] ; Leitch, E. M. ^[1] ; Muchovej, S. J. C. ^[1] ; Pearson, T. J. ^[1] ; Peel, M. W. ^{[2, 8]} ; Readhead, A. C. S. ^[1] ; Sievers, J. ^{[3, 9]} ; Stevenson, M. A. ^[1] ; Taylor, Angela C. ^[5]

Afiliação do(s) autor(es)

^[1] CALTECH, Cahill Ctr Astron & Astrophys, Pasadena, CA 91125 - USA

^[2] Univ Manchester, Sch Phys & Astron, Jodrell Bank Ctr Astrophys, Alan Turing Bldg, Oxford Rd, Manchester M13 9PL, Lancs - England

^[3] McGill Univ, Dept Phys, 3600 Rue Univ, Montreal, PQ H3A 2T8 - Canada

^[4] Univ KwaZulu Natal, Sch Math Stat & Comp Sci, Astrophys & Cosmol Res Unit, Westville Campus, Private Bag X54001, ZA-4000 Durban - South Africa

^[5] Univ Oxford, Subdept Astrophys, Denys Wilkinson Bldg, Keble Rd, Oxford OX1 3RH - England

^[6] Rhodes Univ, Dept Phys & Elect, ZA-6139 Grahamstown - South Africa

^[7] South African Radio Astron Observ, 2 Fir Rd, ZA-7925 Cape Town - South Africa

^[8] Univ Sao Paulo, Inst Fis, Dept Fis Matemat, Rua Matao 1371, Sao Paulo - Brazil

^[9] Univ KwaZulu Natal, Sch Chem & Phys, Westville Campus, Private Bag X54001, ZA-4000 Durban - South Africa

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 485, n. 2, p. 2844-2860, MAY 2019.
• Citações Web of Science: 1

Resumo

The C-Band All-Sky Survey (C-BASS) is a high sensitivity all-sky radio survey at an angular resolution of 45 arcmin and a frequency of 4.7 GHz. We present a total intensity map of the North Celestial Pole (NCP) region of sky, above declination >+80 degrees, which is limited by source confusion at a level of approximate to 0.6mK rms. We apply the template-fitting (cross-correlation) technique to WMAP and Planck data, using the C-BASS map as the synchrotron template, to investigate the contribution of diffuse foreground emission at frequencies similar to 20-40 GHz. We quantify the anomalous microwave emission (AME) that is correlated with far-infrared dust emission. The AME amplitude does not change significantly (< 10 per cent) when using the higher frequency C-BASS 4.7 GHz template instead of the traditional Haslam 408 MHz map as a tracer of synchrotron radiation. We measure template coefficients of 9.93 +/- 0.35 and 9.52 +/- 0.34 K per unit tau(353) when using the Haslam and C-BASS synchrotron templates, respectively. The AME contributes 55 +/- 2 mu K rms at 22.8 GHz and accounts for approximate to 60 per cent of the total foreground emission. Our results show that a harder (flatter spectrum) component of synchrotron emission is not dominant at frequencies greater than or similar to 5 GHz; the best-fitting synchrotron temperature spectral index is beta = -2.91 +/- 0.04 from 4.7 to 22.8 GHz and beta = -2.85 +/- 0.14 from 22.8 to 44.1 GHz. Free-free emission is weak, contributing approximate to 7 mu K rms (approximate to 7 per cent) at 22.8 GHz. The best explanation for the AME is still electric dipole emission from small spinning dust grains. (AU)

• Processo FAPESP: 15/19936-1 - BINGO: uma sonda ultra-sensitiva de hidrogênio e emissão contínua de rádio para medida do setor escuro do universo
• Beneficiário: Michael William Peel
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores