LOFAR MSSS: Discovery of a 2.56 Mpc giant radio galaxy associated with a disturbed galaxy group

Alex Clarke, G. Heald, T. Jarrett, Justin Bray, Martin Hardcastle, Therese Cantwell, Anna Scaife, M Brienza, A Bonafede, Rene Breton, J W Broderick, D Carbone, J H Croston, J S Farnes, J. J. Harwood, V Heesen, A Horneer, A. J. van der Horst, M Iacobelli, W JurusikG Kokotanekov, J P McKean, L. K. Morabito, David Mulcahy, B.S. Nikiel-Wroczynski, E Orru, R Paladino, M Pandey-Pommier, M Pietka, R Pizzo, L Pratley, Christopher Riseley, H J A Rottgering, A. Rowlinson, J Sabater, K Sendlinger, A Shulevski, S Sridhar, A. J. Stewart, C Tasse, S van Velzen, R J van Weeren, M W Wise

    Research output: Contribution to journalArticlepeer-review

    95 Downloads (Pure)


    We report on the discovery in the LOFAR Multifrequency Snapshot Sky Survey (MSSS) of a giant radio galaxy (GRG) with a projected size of 2:56 0:07 Mpc projected on the sky. It is associated with the galaxy triplet UGC9555, within which one is identified as a broad-line galaxy in the Sloan Digital Sky Survey (SDSS) at a redshift of 0:05453 1 10􀀀5, and with a velocity dispersion of 215:86 6:34 km/s. From archival radio observations we see that this galaxy hosts a compact flat-spectrum radio source, and we conclude that it is the active galactic nucleus (AGN) responsible for generating the radio lobes. The radio luminosity distribution of the jets, and the broad-line classification of the host AGN, indicate this GRG is orientated well out of the plane of the sky, making its physical size one of the largest known for any GRG. Analysis of the infrared
    data suggests that the host is a lenticular type galaxy with a large stellar mass (log M=M = 11:56 0:12), and a moderate star formation rate (1:2 0:3 M=year). Spatially smoothing the SDSS images shows the system around UGC9555 to be significantly disturbed, with a prominent extension to the south-east. Overall, the evidence suggests this host galaxy has undergone one or more recent moderate merger events and is also experiencing tidal interactions with surrounding galaxies, which have caused the star formation and provided the supply of gas to trigger and fuel the Mpc-scale radio lobes.
    Original languageEnglish
    JournalAstronomy & Astrophysics
    Early online date24 Apr 2017
    Publication statusPublished - 2017


    Dive into the research topics of 'LOFAR MSSS: Discovery of a 2.56 Mpc giant radio galaxy associated with a disturbed galaxy group'. Together they form a unique fingerprint.

    Cite this