3C 99 is classified as a strong doubled-lobed source and lowfrequency variable object.[8] It has aradio spectrum that appears as steep. When observed withMERLIN at 408MHz, it was shown to have two components that are connected via aradio emission bridge.[6] It'sactive galactic nucleus (AGN) is as radio-loud.[9]
Imaging withVery Long Baseline Interferometry (VLBI), has found both central and eastern components with a totalangular resolution of around 11 x 3milliarcseconds2. There are also emission blob features present inside the central component, with two of them being misaligned with the source's axis. A bright radio component is found, suggesting the central component has a nucleus.[6] The jet region ispolarized to a slight degree.[10]
Further studies have confirmed 3C 99 is a compact steep spectrum (CSS) source.[11] When observed onarcsecond scales, the source is found to contain a triple radio structure with further components ofasymmetrical positions and of differentsurface brightness.[12] There is a one-sidedradio jet described as straight and collimated, connecting both the core region and hotspot feature on the northeast side. The jet also has a bent appearance and it increases slightly before reaching the hotspot region.[13] The estimated dynamical age of the source is around 4 x 105 years.[11] In the galaxy'soptical spectrum, there are narrow permitted lines. Anextended emission-line region (EELR) was discovered in 3C 99.[14]
^Massaro, F.; Harris, D. E.; Liuzzo, E.; Orienti, M.; Paladino, R.; Paggi, A.; Tremblay, G. R.; Wilkes, B. J.; Kuraszkiewicz, J.; Baum, S. A.; O'Dea, C. P. (September 2015). "The Chandra Survey of Extragalactic Sources in the 3CR Catalog: X-ray Emission from Nuclei, Jets, and Hotspots in the Chandra Archival Observations".The Astrophysical Journal Supplement Series.220 (1): 5.arXiv:1609.07145.Bibcode:2015ApJS..220....5M.doi:10.1088/0067-0049/220/1/5.ISSN0067-0049.
^Mantovani, F.; Junor, W.; Bondi, M.; Cotton, W.; Fanti, R.; Padrielli, L.; Nicolson, G.; Salerno, E. (1997-12-05),Large bent jets in the inner region of CSSs,arXiv:astro-ph/9712084
