However, the calibration and imaging of GWB data is a complex procedure. The wide bandwidth of the upgraded GMRT simultaneously provides increased sensitivity and opportunity for in-band spectral index studies. Thirteen clusters in our sample, including J0034, have uGMRT GWB band 3 (250–500 MHz) observations. This study is a precursor to studies of larger samples exploring lower mass and higher redshift cluster sample studies such as the MeerKAT Extended Relics, Giant Halos, and Extragalactic Radio Sources (MERGHERS) survey and the MeerKAT Absorption Line Survey (MALS ). The SPT sample overlaps with ours at higher redshifts however, it does not cover lower redshifts ( z < 0.33). We also cover lower mass clusters compared to the Planck sample. Our sample covers a wider redshift range compared to both samples. In Figure 2, we compare our sample of 40 clusters to Planck and SPT samples, which are the most recent statistical studies using SZ-selected cluster samples. This completeness is derived from the mass completeness and the available radio information (30/40). We then applied a mass and redshift cut of M 500, SZ> 4 × 10 14 M ⊙ and 0.1 4.5 × 10 14 M ⊙, we derive our sample completeness to be 68%. įor our sample, we considered all the clusters with an SNR > 5. A major open question is the origin of the re-accelerated cosmic ray particles. Although the re-acceleration theory is widely accepted, there are still a few aspects that need further investigation. This difference may be due to the different time-scales of boosting the SZ vs X-ray emission during mergers. Samples selected via their Sunyaev-Zel’dovich signal (SZ ) show a higher detection rate than X-ray-selected samples. Studies have shown that cluster selection methods affect the resulting scaling relations. The power of the radio emission has been found to correlate with thermal host cluster properties, with non-detections lying below the correlation and with sources that exhibit ultra-steep spectra ( α 1 ≳ 1.5) that populate the region between the correlation and upper limits, as predicted by the re-acceleration model. The ∼Mpc-scale emission has mostly been found in massive (M 500, S Z > 4 × 10 14 M ⊙) clusters with X-ray and optical merger signatures. A strong dynamical link has been found with respect to the host clusters. According to this model, a pool of pre-existing electrons is re-accelerated through second order Fermi mechanisms by ICM turbulence developing during cluster mergers. The second model is the primary ‘re-acceleration’ model. However, due to the severe artefacts in the field, further analysis is required to improve the image quality. We conclude that the experimental spam wideband pipeline produces the best results for this particular field. Due to the complexity of the ACT−CL J0034.4+0225 field, we use three pipelines to process the wideband data. We present an overview of our sample, confirm the detection of a radio halo in ACT−CL J0034.4+0225, and compare the narrowband and wideband analysis results for this cluster. We use the upgraded Giant Metrewave Radio Telescope (uGMRT) for targeted radio observations of a sample of 40 clusters. We aim to apply these techniques to the study of radio halos, relics and radio mini-halos using a uniformly selected and complete sample of galaxy clusters selected via the Sunyaev-Zel’dovich (SZ) effect by the Atacama Cosmology Telescope (ACT) project, and its polarimetric extension (ACTPol). In this study, we focus on the development of interferometric techniques for extracting extended, faint diffuse emissions in the presence of bright, compact sources in wide-field and broadband continuum imaging data. Current formation theories cannot fully account for some of the observed properties of this emission. Low frequency radio observations of galaxy clusters are a useful probe of the non-thermal intracluster medium (ICM), through observations of diffuse radio emission such as radio halos and relics.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |