10C Survey of Radio Sources at 15.7 GHz: II - First Results
Matthew L. Davies, Thomas M. O. Franzen, Elizabeth M. Waldram, Keith J. B. Grainge, Michael P. Hobson, Natasha Hurley-Walker, Anthony Lasenby, Malak Olamaie, Gu… 展开作者
Matthew L. Davies, Thomas M. O. Franzen, Elizabeth M. Waldram, Keith J. B. Grainge, Michael P. Hobson, Natasha Hurley-Walker, Anthony Lasenby, Malak Olamaie, Guy G. Pooley, Julia M. Riley, Carmen Rodriguez-Gonzalvez, Richard D. E. Saunders, Anna M. M. Scaife, Michel P. Schammel, Paul F. Scott, Timothy W. Shimwell, David J. Titterington, Jonathan T. L. Zwart
备注:
15 pages, 12 figures, landscape page (Table 1) is included on final page, submitted to MNRAS. Modified to compare to latest version of the de Zotti model. Added further detail about checks to flux-density scale
The first results from the Tenth Cambridge (10C) Survey of Radio Sources, carried out using the AMI Large Array (LA) at an observing frequency of 15.7 GHz, are presented. The survey fields cover an area of approximately 27 sq. degrees to a flux-density completeness of 1 mJy. Results for some deeper areas, covering approximately 12 sq. degrees, wholly contained within the total areas and complete to 0.5 mJy, are also presented. The completeness for both areas is estimated to be at least 93 per cent.
The source catalogue contains 1897 entries and is available at www.mrao.cam.ac.uk/surveys/10C. It has been combined with that of the 9C Survey to calculate the 15.7-GHz source counts. A broken power law is found to provide a good parameterisation of the differential count between 0.5 mJy and 1 Jy. The measured count has been compared to that predicted by de Zotti et al. (2005). The model displays good agreement with the data at the highest flux densities but under-predicts the integrated count between 0.5 mJy and 1 Jy by about 30 per cent.
Entries from the source catalogue have been matched to those contained in the catalogues of NVSS and FIRST (both of which have observing frequencies of 1.4 GHz). This matching provides evidence for a shift in the typical 1.4-to-15.7-GHz spectral index of the 15.7-GHz-selected source population with decreasing flux density towards sub-mJy levels - the spectra tend to become less steep.
Automated methods for detecting extended sources have been applied to the data; approximately 5 per cent of the sources are found to be extended relative to the LA synthesised beam of approximately 30 arcsec. Investigations using higher-resolution data showed that most of the genuinely extended sources at 16 GHz are classical doubles, although some nearby galaxies and twin-jet sources were also identified.
High significance detection at 4.8 GHz of the radio halo in the Coma galaxy cluster with the Sardinia Radio Telescope
INAF-Osservatorio Astronomico di Cagliari(意大利国家天体物理研究所卡利亚里天文台);Dipartimento di Fisica e Astronomia, Università di Bologna(博洛尼亚大学物理与天文学系);INAF, Istituto di Radio Astronomia(意大利国家天体物理研究所射电天文研究所)
Observations of radio relics at very high frequency (>10 GHz) can help to understand how particles age and are (re-)accelerated in galaxy cluster outskirts and how magnetic fields are amplified in these environments. In this work, we present new single-dish 18.6 GHz Sardinia Radio Telescope and 14.25 GHz Effelsberg observations of the well known northern radio relic of CIZA J2242.8+5301. We detected the relic which shows a length of $\sim$1.8 Mpc and a flux density equal to $\rm S_{14.25\,GHz}=(9.5\pm3.9)\,mJy$ and $\rm S_{18.6\,GHz}=(7.67\pm0.90)\,mJy$ at 14.25 GHz and 18.6 GHz respectively. …
First detection at 5.5 and 9 GHz of the radio relics in bullet cluster with ATCA
我们在这里提出的结果,在5.5和9 GHz的子弹星系团1 E 0657-55.8与澳大利亚望远镜紧凑阵列(ATCA)的观测。我们的研究结果表明,在集群中的漫发射检测。我们的研究结果与Shimwell et al.(2014)和Shimwell et al.(2015)在1.1-3.1 GHz的先前观察结果一致。扩散结构(遗迹区A和B和射电晕)的形态与以前的研究报告一致。我们的研究结果表明,陡峭的光谱指数在较高的频率(在和大于5.0 GHz)的区域A。谱可以很好地用破幂律拟合。我们讨论了最近的一些理论模型解释这种突破的幂律谱的可能性,并发现一个修改后的扩散冲击加速(DSA)模型或湍流再加速模型可能是相关的。需要在高频(5 GHz及以上)进行深层射电观测,以便与该模型进行详细比较。
Detection of quasi-periodic oscillations in the 37 GHz radio light curve of the blazar Ton 599 during 1990-2020
Xinjiang Astronomical Observatory, Chinese Academy of Sciences(中国科学院新疆天文台);Aryabhatta Research Institute of Observational Sciences (ARIES)(阿亚巴塔观测科学研究所);Radio Astronomy Laboratory of Crimean Astrophysical Observatory(克里米亚天体物理台射电天文实验室);Indian Institute of Astrophysics (IIA)(印度天体物理研究所);Department of Physics, The College of New Jersey(新泽西学院物理系);FINCA, University of Turku(图尔库大学FINCA);Tuorla Observatory, Department of Physics and Astronomy, University of Turku(图尔库大学图奥拉天文台物理与天文学系);Tsung-Dao Lee Institute, Shanghai Jiao Tong University(上海交通大学李政道研究所)
We present a weak lensing analysis of the 3 GHz VLA radio survey of the COSMOS field, which we correlate with overlapping HST-ACS optical observations using both intrinsic galaxy shape and cosmic shear correlation statistics. After cross-matching sources between the two catalogues, we measure the correlations of galaxy position angles and find a Pearson correlation coefficient of $0.14 \pm 0.03$. This is a marked improvement from previous studies which found very weak, or non-existent correlations, and gives insight into the emission processes of radio and optical galaxies. We also extract pow…
Radio-loud active galactic nuclei (AGNs), hosting powerful relativistic jet outflows, provide an excellent laboratory for studying jet physics. Very long baseline interferometry (VLBI) enables high-resolution imaging on milli-arcsecond (mas) and sub-mas scales, making it a powerful tool to explore the inner jet structure, shedding light on the formation, acceleration and collimation of AGN jets. In this paper, we present Very Long Baseline Array (VLBA) observations of ten radio-loud AGNs at 43 and 86~GHz, which were selected from the {\it Planck} catalogue of compact sources and are among the …