English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

(Abridged) The Census of High- and Medium-mass Protostars (CHaMP) is thefirst large-scale (280 degree<l<300 degree, -4 degree<b<2 degree), unbiased,sub-parsec resolution survey of Galactic molecular clumps and their embeddedstars. Barnes et al. (2011) presented the source catalog of ~300 clumps basedon HCO+(1-0) emission, used to estimate masses M. Here we use archivalmid-infrared to mm continuum data to construct spectral energy distributions.Fitting two-temperature grey-body models, we derive bolometric luminosities, L.We find the clumps have 10Lsun<L<1E6.5Lsun and 0.1<L/M<1E3, consistent withtheoretical expectations of a clump population that spans a range ofinstantaneous star formation efficiencies from 0 to ~50%. We thus expect L/M tobe a useful, strongly-varying indicator of clump evolution during the starcluster formation process. We find correlations of the ratio of warm to coldcomponent fluxes and of cold component temperature with L/M. We also find anear linear relation between L/M and Spitzer-IRAC specific intensity (surfacebrightness), which may thus also be useful as a star formation efficiencyindicator. The lower bound of the clump $L/M$ distribution suggests the starformation efficiency per free-fall time is epsilon<0.2. We do not find strongcorrelations of L/M with mass surface density, velocity dispersion or virialparameter. We find a linear relation between L and L_{HCO+(1-0}}, although withlarge scatter for any given individual clump. Fitting together withextragalactic systems, the linear relation still holds, extending over 10orders of magnitude in luminosity. The complete nature of the CHaMP survey overa several kiloparsec-scale region allows us to derive a measurement at anintermediate scale bridging those of individual clumps and whole galaxies.

The Galactic Census of High- and Medium-mass Protostars. II. Luminosities and Evolutionary States of a Complete Sample of Dense Gas Clumps