@ARTICLE{2026A&A...711A..91A,
       author = {{Arroyo-Polonio}, A. and {V{\'\i}lchez}, J.~M. and {Iglesias-P{\'a}ramo}, J. and {Kehrig}, C. and {P{\'e}rez-Montero}, E. and {Amor{\'\i}n}, R. and {P{\'e}rez-D{\'\i}az}, B. and {Hayes}, M. and {Breda}, I. and {S{\'a}nchez Almeida}, J. and {Gim{\'e}nez Alcazar}, A. and {Gonz{\'a}lez-Otero}, M.},
        title = "{Not so isolated: Green Pea galaxies in overdense environments revealed by VLT/MUSE}",
      journal = {\aap},
     keywords = {HII regions, galaxies: abundances, galaxies: evolution, galaxies: interactions, galaxies: starburst, galaxies: star formation, Astrophysics of Galaxies},
         year = 2026,
        month = jul,
       volume = {711},
          eid = {A91},
        pages = {A91},
     abstract = "{Context. Green Pea galaxies (GPs) are local starburst galaxies that
        serve as analogs for high-redshift star-forming galaxies,
        particularly Lyman continuum leakers. Historically considered
        isolated dwarfs, it remains debated whether their starbursts are
        driven by internal secular processes or external triggers. Aims.
        We aim to constrain the role of the environment in this
        triggering. Specifically, we test whether external influence
        comes from close galaxy─galaxy interactions or more diffuse
        processes, such as gas accretion within overdense regions.
        Methods. We analyze VLT/MUSE observations of 24 GPs at z
        {\ensuremath{\sim}} 0.2, searching for galaxies with spectral
        line features to identify companions. We derive key physical
        properties (extinction, star-formation rates, stellar mass, age,
        metallicity) for GPs and companions and estimate the dynamical
        mass of the groups. Results. We identify 22 emission-line
        galaxies, 11 of which are companions
        (|{\ensuremath{\Delta}}v|{\ensuremath{\leq}}500 km
        s$^{{\ensuremath{-}}1}$). We find a high companion fraction (33
        {\ensuremath{-}} 8   + 11   \%) and a {\ensuremath{\sim}}1 dex
        excess in number density compared to the field, confirming that
        GPs reside in overdense environments. However, companions
        typically lie at projected separations of {\ensuremath{\sim}}100
        kpc with no evidence of ongoing interactions. Physically, while
        both populations show star-forming excitation, GPs form a
        homogeneous class of young (stellar mass-weighted age
        {\ensuremath{\sim}}230 Myr), metal-poor, high-sSFR starbursts
        with elevated velocity dispersions. In contrast, companions are
        more evolved ({\ensuremath{\sim}}1.6 Gyr) and heterogeneous,
        spanning broader ranges in stellar mass, metallicity, and dust
        attenuation. The inferred group dynamical masses are
        {\ensuremath{\sim}}3 dex higher than total stellar masses,
        suggesting significant dark matter and neutral gas content.
        Conclusions. The GPs do not appear to be triggered by ongoing
        major mergers with close (10─30 kpc) companions. Instead,
        results favor a scenario where GPs are transient starbursts in
        overdense regions, plausibly sustained by gas accretion.
        However, the limited spatial resolution prevents us from ruling
        out very close mergers ({\ensuremath{\lesssim}}10 kpc).
        Furthermore, the high dynamical-to-stellar mass ratios allow for
        substantial nonstellar mass components (i.e., dark matter and/or
        neutral gas) in these systems.}",
          doi = {10.1051/0004-6361/202659076},
archivePrefix = {arXiv},
       eprint = {2605.03676},
 primaryClass = {astro-ph.GA},
       adsurl = {https://ui.adsabs.harvard.edu/abs/2026A&A...711A..91A},
      adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}