2015ApJ...807L..25K -
Astrophys. J., 807, L25 (2015/July-2)
Tracing embedded stellar populations in clusters and galaxies using molecular emission: methanol as a signature of the low-mass end of the IMF.
KRISTENSEN L.E. and BERGIN E.A.
Abstract (from CDS):
Most low-mass protostars form in clusters, in particular high-mass clusters; however, how low-mass stars form in high-mass clusters and what the mass distribution is are still open questions both in our own Galaxy and elsewhere. To access the population of forming embedded low-mass protostars observationally, we propose using molecular outflows as tracers. Because the outflow emission scales with mass, the effective contrast between low-mass protostars and their high-mass cousins is greatly lowered. In particular, maps of methanol emission at 338.4 GHz (J = 70-60A+) in low-mass clusters illustrate that this transition is an excellent probe of the low-mass population. We present here a model of a forming cluster where methanol emission is assigned to every embedded low-mass protostar. The resulting model image of methanol emission is compared to recent ALMA observations toward a high-mass cluster and the similarity is striking: the toy model reproduces observations to better than a factor of two and suggests that approximately 50% of the total flux originates in low-mass outflows. Future fine-tuning of the model will eventually make it a tool for interpreting the embedded low-mass population of distant regions within our own Galaxy and ultimately higher-redshift starburst galaxies, not just for methanol emission but also water and high-J CO.
Abstract Copyright:
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Journal keyword(s):
astrochemistry - ISM: jets and outflows - line: profiles - stars: formation - stars: winds, outflows
Simbad objects:
11
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