The radio emission from Active Galactic Nuclei
| Autor: | Radcliffe, J. F., Barthel, P. D., Garrett, M. A., Beswick, R. J., Thomson, A. P., Muxlow, T. W. B. |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | A&A 649, L9 (2021) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1051/0004-6361/202140791 |
| Popis: | For nearly seven decades astronomers have been studying active galaxies, that is to say galaxies with actively accreting central supermassive black holes, AGN. A small fraction of these are characterized by luminous, powerful radio emission: this class is known as radio-loud. A substantial fraction, the so-called radio-quiet AGN population, displays intermediate or weak radio emission. However, an appreciable fraction of strong X-rays emitting AGN are characterized by the absence of radio emission, down to an upper limit of about $10^{-7}$ times the luminosity of the most powerful radio-loud AGN. We wish to address the nature of these - seemingly radio-silent - X-ray-luminous AGN and their host galaxies: is there any radio emission, and if so, where does it originate? Focusing on the GOODS-N field, we examine the nature of these objects employing stacking techniques on ultra-deep radio data obtained with the JVLA. We combine these radio data with Spitzer far-infrared data. We establish the absence, or totally insignificant contribution of jet-driven radio-emission in roughly half of the otherwise normal population of X-ray luminous AGN, which appear to reside in normal star-forming galaxies. We conclude that AGN- or jet-driven radio emission is simply a mechanism that may be at work or may be dormant in galaxies with actively accreting black holes. The latter can be classified as radio-silent AGN. Comment: Accepted as an A&A Letter. 5 pages, 4 figures (v2 - language edited version) |
| Databáze: | arXiv |
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