Evolution of young protoclusters embedded in dense massive clumps. A new grid of population synthesis SED models and a new set of L/M evolutionary tracks

Abstract

A grid of 20 millions 3-1100$\mu$m SED models is presented for synthetic young clusters embedded in dense clumps. The models depend on four primary parameters: the clump mass M${}_{clump}$ and dust temperature T${}_{dust}$, the fraction of mass f${}_{core}$ locked in dense cores, and the age of the clump t${}_{SF}$. We populate the YSO clusters using the IMF from Kroupa(2001) and the YSOs SED models grid of Robitaille et al. (2006). We conduct extensive testing of SED fitting using a simulated dataset and we find that M${}_{clump}$ essentially depends on the submillimeter portion of the SED, while T${}_{dust}$ is mostly determined from the shape of the SED in the 70-350$\mu$m range. Thanks to the large number of models computed we verify that the combined analysis of L/M, [8-24] and [24-70] colours removes much of the SEDs f${}_{core}$-t${}_{SF}$ degeneracy. The L/M values are particularly useful to diagnose f${}_{core}$. L/M$\le$1 identifies protoclusters with f${}_{core}\le$0.1 and t${}_{SF}\le 10^5$ years, while L/M$\ge$10 excludes f${}_{core}\le$0.1. We characterize lower limits of L/M where ZAMS stars are not found in models, and we also find models with L/M $\ge$10 and no ZAMS stars, in which [8-24]$\ge 0.8\pm 0.1$ independently from M${}_{clump}$, temperature and luminosity. This is the first set of synthesis SED models suited to model for embedded and unresolved clusters of YSOs. A set of new evolutionary tracks in the L/M diagram is also presented.

MNRAS, Accepted

References in corpus (12)

• Cold Dark Clouds: The Initial Conditions for Star Formation
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• Properties of Hi-GAL clumps in the inner Galaxy]{The Hi-GAL compact source catalogue. I. The physical properties of the clumps in the inner Galaxy ($-71.0^{\circ }<\ell <67.0^{\circ }$)
• A modular set of synthetic spectral energy distributions for young stellar objects
• Infall Motions in Massive Star-Forming Regions: Results from Years 1 & 2 of the MALT90 Survey
• Massive 70 micron quiet clumps I: evidence of embedded low/intermediate-mass star formation activity
• Distance biases in the estimation of the physical properties of Hi-GAL compact sources-I. Clump properties and the identification of high-mass star forming candidates
• An analysis of star formation with Herschel in the Hi-GAL Survey. II. The tips of the Galactic bar
• Stellar age spreads in clusters as imprints of cluster-parent clump densities
• The initial conditions of high-mass star formation: radiative transfer models of IRDCs seen in the Herschel Hi-GAL survey
• Photon Dominated Regions in NGC 3603
• Do individual Spitzer young stellar object candidates enclose multiple UKIDSS sources?