Astrophys. J., 839, 113-113 (2017/April-3)
The star-formation law in Galactic high-mass star-forming molecular clouds.
RETES-ROMERO R., MAYYA Y.D., LUNA A. and CARRASCO L.
Abstract (from CDS):
We study the star-formation (SF) law in 12 Galactic molecular clouds with ongoing high-mass star-formation (HMSF) activity, as traced by the presence of a bright IRAS source and other HMSF tracers. We define the molecular cloud (MC) associated with each IRAS source using 13CO line emission, and count the young stellar objects (YSOs) within these clouds using GLIMPSE and MIPSGAL 24 µm Spitzer databases. The masses for high-luminosity YSOs (Lbol > 10 L☉) are determined individually using pre-main-sequence evolutionary tracks and the evolutionary stages of the sources, whereas a mean mass of 0.5 M☉ was adopted to determine the masses in the low-luminosity YSO population. The star-formation rate surface density (ΣSFR) corresponding to a gas surface density (Σgas) in each MC is obtained by counting the number of the YSOs within successive contours of 13CO line emission. We find a break in the relation between ΣSFR and Σgas, with the relation being a power law (ΣSFR∝ΣgasN) with the index N varying between 1.4 and 3.6 above the break. The Σgas at the break is between 150-360 M☉ pc–2 for the sample clouds, which compares well with the threshold gas density found in recent studies of Galactic star-forming regions. Our clouds treated as a whole lie between the Kennicutt relation and the linear relation for Galactic and extra-galactic dense star-forming regions. We find a tendency for the high-mass YSOs to be found preferentially in dense regions at densities higher than 1200 M☉ pc–2 (∼0.25 g cm–2).
© 2017. The American Astronomical Society. All rights reserved.
H II regions - ISM: clouds - stars: formation - stars: formation
VizieR on-line data:
<Available at CDS (J/ApJ/839/113): table1.dat table2.dat table4.dat>
Tables 1-2: [RML2017] MCNN N=12 among (Nos MC1-MC81). Table 4: [RML2017] MCNN MNNN N=1057 among (Nos MC1 M1 to MC81 M4), [RML2017] MCNN GNNN N=4846 among (Nos MC1 G1 to MC81 G9).
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