NGC 5135 has well defined spiral arms and is considered a grand design spiral galaxy. There is star formation along the leading edges of the arms.[3] There are dust lanes along the bar that curve towards the centre of galaxy.[4] Spiral arms become less well structured in the central regions.[3]
NGC 5135 is a bright source in infrared light and with total infrared luminosity of 1011.16−1011.23L☉ is considered a luminous infrared galaxy.[5][6] Also strong ultraviolet emission was detected in the central 2 arcseconds of the galaxy, with a dozen of prominent knots, indicative of a recent starburst.[7] The total star formation rate in the galaxy is estimated to be 15.61 ± 1.87 M☉ per year.[6]Knots of gas measuring 45–180 parsecs across are detected along the inner spiral arms in CO(6-5) imaging and some of them are associated with starburst regions.[8]
The nucleus of NGC 5135 has been found to be active and it has been categorised as a type II Seyfert galaxy.[9] The most accepted theory for the energy source of active galactic nuclei is the presence of an accretion disk around a supermassive black hole. The mass of the black hole in the centre of NGC 5135 is estimated to be 107.29 (19 million) M☉.[10]
The active nucleus is obscured in X-rays by Compton-thick material with a column density of 6.7+16.6 −2.8×1024/cm2.[11] An ionization cone has been detected in [Si vi] emission that extends for 600 parsec from the nucleus. To the ionization of the gas apart from the active nucleus also contribute supernova remnant shocks and young stars.[12]
^Gonzalez Delgado, Rosa M.; Heckman, Timothy; Leitherer, Claus; Meurer, Gerhardt; Krolik, Julian; Wilson, Andrew S.; Kinney, Anne; Koratkar, Anuradha (20 September 1998). "Ultraviolet-Optical Observations of the Seyfert 2 Galaxies NGC 7130, NGC 5135, and IC 3639: Implications for the Starburst–Active Galactic Nucleus Connection". The Astrophysical Journal. 505 (1): 174–198. arXiv:astro-ph/9806107. Bibcode:1998ApJ...505..174G. doi:10.1086/306154. S2CID119098033.
^For, B-Q; Staveley-Smith, L; Westmeier, T; Whiting, M; Oh, S-H; Koribalski, B; Wang, J; Wong, O I; Bekiaris, G; Cortese, L; Elagali, A; Kleiner, D; Lee-Waddell, K; Madrid, J P; Popping, A; Rhee, J; Reynolds, T N; Collier, J D; Phillips, C J; Voronkov, M A; Müller, O; Jerjen, H (11 November 2019). "WALLABY early science − V. ASKAP H i imaging of the Lyon Group of Galaxies 351". Monthly Notices of the Royal Astronomical Society. 489 (4): 5723–5741. doi:10.1093/mnras/stz2501. hdl:1885/266365.