Galaxy And Mass Assembly (GAMA): a "no smoking" zone for giant elliptical galaxies?

Habib G. Khosroshahi, Mojtaba Raouf, Halime Miraghaei, Sarah Brough, Darren J. Croton, Simon Driver, Alister Graham, Ivan Baldry, Michael Brown, Matt Prescott, Lingyu Wang

    Research output: Contribution to journalArticlepeer-review

    17 Citations (Scopus)

    Abstract

    We study the radio emission of the most massive galaxies in a sample of dynamically relaxed and unrelaxed galaxy groups from the Galaxy and Mass Assembly survey. The dynamical state of the group is defined by the stellar dominance of the brightest group galaxy (BGG), e.g., the luminosity gap between the two most luminous members, and the offset between the position of the BGG and the luminosity centroid of the group. We find that the radio luminosity of the largest galaxy in the group strongly depends on its environment, such that the BGGs in dynamically young (evolving) groups are an order of magnitude more luminous in the radio than those with a similar stellar mass but residing in dynamically old (relaxed) groups. This observation has been successfully reproduced by a newly developed semi-analytic model that allows us to explore the various causes of these findings. We find that the fraction of radio-loud BGGs in the observed dynamically young groups is similar to 2 times that of the dynamically old groups. We discuss the implications of this observational constraint on the central galaxy properties in the context of galaxy mergers and the super massive black hole accretion rate.

    Original languageEnglish
    Article number81
    Number of pages9
    JournalThe Astrophysical Journal: an international review of astronomy and astronomical physics
    Volume842
    Issue number2
    DOIs
    Publication statusPublished - 20 Jun 2017

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