Characterizing the diffuse foreground for redshifted 21-cm HI signal: GMRT 153 MHz observation

7th International Conference on Gravitation and Cosmology

Ghosh, A.^1 ; Prasad, J.^2 ; Bharadwaj, S.^1 ; Ali, S.S.^3 ; Chengalur, J.N.^4

Department of Physics and Meteorology, And Centre for Theoretical Studies, IIT, Kharagpur 721302, India^1

IUCAA, Pune University Campus, Post Bag 4, Ganeshkhind, Pune 411007, India^2

Department of Physics, Jadavpur University, Kolkata 700032, India^3

National Centre for Radio Astrophysics, TIFR, Post Bag 3, Ganeshkhind, Pune 411007, India^4

关键词: Angular power spectrum;    Angular spectra;    Diffuse emission;    Diffuse radiation;    Galactic latitude;    Multi frequency;    Power law behaviour;    Statistical properties;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/484/1/012032/pdf
DOI  :  10.1088/1742-6596/484/1/012032

来源: IOP

【 摘 要 】

Detailed knowledge of the foreground structure on the angular scales of ∼ 1° to sub-arcminute will be essential for extracting the redshifted 21-cm HI signal from the observed data. We have presented results from the GMRT observations at 153 MHz, which was used to characterize the statistical properties of the diffuse radiation, using the multi-frequency angular power spectrum, across sub-degree angular scales. We have detected fluctuations in the diffuse emission on angular scales greater than 10' in a low galactic latitude area. The total intensity angular spectrum shows a power-law behaviour, while the detection of diffuse emission at smaller angular scales is limited by residual point sources. Also, we have estimated the level of foreground contamination.