24 research outputs found

    The galactic census of high- and medium-mass protostars - I. Catalogs and first results from Mopra HCO+ maps

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    The Census of High- and Medium-mass Protostars (CHaMP) is the first large-scale, unbiased, uniform mapping survey at sub-parsec scale resolution of 90 GHz line emission from massive molecular clumps in the Milky Way. We present the first Mopra (ATNF) maps of the CHaMP survey region (300{\deg}>l>280{\deg}) in the HCO+ J=1-0 line, which is usually thought to trace gas at densities up to 10^11 m-3. In this paper we introduce the survey and its strategy, describe the observational and data reduction procedures, and give a complete catalogue of moment maps of the HCO+ J=1-0 emission from the ensemble of 301 massive molecular clumps. From these maps we also derive the physical parameters of the clumps, using standard molecular spectral-line analysis techniques. This analysis yields the following range of properties: integrated line intensity 1-30 K km s-1, peak line brightness 1-7 K, linewidth 1-10 km s-1, integrated line luminosity 0.5-200 K km s-1 pc^2, FWHM size 0.2-2.5 pc, mean projected axial ratio 2, optical depth 0.08-2, total surface density 30-3000 M{\sun} pc-2, number density 0.2-30 x 10^9 m-3, mass 15-8000 M{\sun}, virial parameter 1-55, and total gas pressure 0.3-700 pPa. We find that the CHaMP clumps do not obey a Larson-type size-linewidth relation. Among the clumps, there exists a large population of subthermally excited, weakly-emitting (but easily detectable) dense molecular clumps, confirming the prediction of Narayanan et al. (2008). These weakly-emitting clumps comprise 95% of all massive clumps by number, and 87% of the molecular mass, in this portion of the Galaxy; their properties are distinct from the brighter massive star-forming regions that are more typically studied. If the clumps evolve by slow contraction, the 95% of fainter clumps may represent a long-lived stage of pressure-confined, gravitationally stable massive clump evolution, while the CHaMP ... (abridged)Comment: Submitted to ApJ; edited to referee's comments. 98 pages, 81 figures. For more information, see http://www.astro.ufl.edu/cham

    Women entrepreneurs in Saudi Arabia: Creative responses to gendered opportunities

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    Female entrepreneurs in the Kingdom of Saudi Arabia (KSA) experience barriers to their action which require creative strategies to navigate. Despite regulatory efforts to advance female entrepreneurial ventures, sociocultural ascriptions remain and these can be detrimental to women’s business experiences. This chapter explores the exogenous and endogenous circumstances integral to establishing a new venture in Saudi Arabia and the hindrances these can pose to female entrepreneurship. Barriers are identified that frame female entrepreneurial action and their creative responses are highlighted to demonstrate how they can play a crucial role in formulating women’s entrepreneurial identities and their entrepreneurial action. A conceptual framework for future research is outlined that seeks to understand these creative responses
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