2015ApJ...803...89D

We present the first high-angular resolution study of the MonR2 star-forming complex carried out with the Submillimeter Array at (sub-)millimeter wavelengths. We image the continuum and molecular line emission toward the young stellar objects in MonR2 at 0.85 and 1.3 mm, with resolutions ranging from 0". 5 to ∼3". While free-free emission dominates the IRS1 and IRS2 continuum, dust thermal emission prevails for IRS3 and IRS5, giving envelope masses of ∼0.1-0.3 M_☉. IRS5 splits into at least two sub-arcsecond scale sources, IRS5B and the more massive IRS5A. Our ¹²CO(2-1) images reveal 11 previously unknown molecular outflows in the MonR2 clump. Comparing these outflows with known IR sources in the IRS5 and IRS3 subclusters allows for tentative identification of driving stars. Line images of molecular species such as CH₃ CN or CH₃OH show that, besides IRS3 (a well-known hot molecular core), IRS5 is also a chemically active source in the region. The gas excitation temperature derived from CH₃ CN lines toward IRS5 is 144±15 K, indicating a deeply embedded protostar at the hot-core evolutionary stage. Spectral energy distribution fitting of IRS5 gives a mass of ∼7 M M_☉ and a luminosity of 300 L_☉ for the central source. The derived physical properties of the CO outflows suggest that they contribute to the turbulent support of the MonR2 complex and to the gas velocity dispersion in the clump's center. The detection of a large number of CO outflows widespread across the region supports the competitive accretion scenario as origin of the MonR2 star cluster.