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Expanded very large array continuum observations toward hot molecular core candidates


Hofner, P and Kurtz, S and Ellingsen, SP and Menten, KM and Wyrowski, F and Araya, ED and Loinard, L and Rodriguez, LF and Cesaroni, R, Expanded very large array continuum observations toward hot molecular core candidates, The Astrophysical Journal Letters, 739, (1) Article L17. ISSN 2041-8205 (2011) [Refereed Article]

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Copyright 2011 The American Astronomical Society

DOI: doi:10.1088/2041-8205/739/1/L17


We have used the Expanded Very Large Array (EVLA) with two 1 GHz wide bands to obtain K-band (1.3 cm) continuum observations toward the following five hot molecular core candidates: IRAS 18151 – 1208, IRAS 18182 – 1433, IRAS 18345 – 0641, IRAS 18470 – 0044, and IRAS 19012 + 0536. The sources were selected from the 2002 list of Sridharan et al. and are characterized by high FIR luminosity, dense molecular and dust condensations, massive large-scale CO flows, and the absence of strong cm continuum emission. These properties are indicative of massive star-forming regions in an evolutionary phase prior to ultra- or hypercompact H II regions. We detect a total of 10 individual 1.3 cm continuum sources toward this sample, and derive in-band spectral indices between 19.3 and 25.5 GHz consistent with thermal free-free emission, for all sources except component A in IRAS 18182 – 1433, which has a negative spectral index indicative of synchrotron emission. We suggest that in most cases the 1.3 cm sources are due to shock-induced ionization, rather than direct photoionization by massive objects. The momentum rate present in these ionized flows is sufficient to drive the large-scale molecular flows. We discuss a number of morphological features supporting this hypothesis. The present observations demonstrate that the EVLA has sufficient sensitivity to study the regions near very young massive stars in the cm continuum.

Item Details

Item Type:Refereed Article
Keywords:ISM, jets, outflows, radio continuum, stars, star formation
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Ellingsen, SP (Professor Simon Ellingsen)
ID Code:73069
Year Published:2011
Web of Science® Times Cited:8
Deposited By:Mathematics and Physics
Deposited On:2011-09-09
Last Modified:2017-11-03

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