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The molecular environment of the Galactic star forming region G19.61–0.23

Santangelo, G. and Testi, L. and Leurini, S. and Walmsley, C. M. and Cesaroni, R. and Bronfman, L. and Carey, S. and Gregorini, L. and Menten, K. M. and Molinari, S. and Noriega-Crespo, A. and Olmi, L. and Schuller, F. (2010) The molecular environment of the Galactic star forming region G19.61–0.23. Astronomy and Astrophysics, 520 . A50. ISSN 0004-6361.

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Context. Although current facilities allow the study of Galactic star formation at high angular resolution, our current understanding of the high-mass star-formation process is still very poor. In particular, we still need to characterize the properties of clouds giving birth to high-mass stars in our own Galaxy and use them as templates for our understanding of extragalactic star formation. Aims. We present single-dish (sub)millimeter observations of gas and dust in the Galactic high-mass star-forming region G19.61–0.23, with the aim of studying the large-scale properties and physical conditions of the molecular gas across the region. The final aim is to compare the large-scale (about 100 pc) properties with the small-scale (about 3 pc) properties and to consider possible implications for extragalactic studies. Methods. We have mapped CO isotopologues in the J = 1–0 transition using the FCRAO-14m telescope and the J = 2–1 transition using the IRAM-30m telescope. We have also used APEX 870 μm continuum data from the ATLASGAL survey and FCRAO supplementary observations of the ^(13)CO J = 1–0 line from the BU-FCRAO Galactic Ring Survey, as well as the Spitzer infrared Galactic plane surveys GLIMPSE and MIPSGAL to characterize the star-formation activity within the molecular clouds. Results. We reveal a population of molecular clumps in the ^(13)CO(1–0) emission, for which we derived the physical parameters, including sizes and masses. Our analysis of the ^(13)CO suggests that the virial parameter (ratio of kinetic to gravitational energy) varies over an order of magnitude between clumps that are unbound and some that are apparently “unstable”. This conclusion is independent of whether they show evidence of ongoing star formation. We find that the majority of ATLASGAL sources have MIPSGAL counterparts with luminosities in the range 10^(4)–5×10^4 L_☉ and are presumably forming relatively massive stars. We compare our results with previous extragalactic studies of the nearby spiral galaxies M 31 and M 33; and the blue compact dwarf galaxy Henize 2–10. We find that the main giant molecular cloud surrounding G19.61–0.23 has physical properties typical for Galactic GMCs and which are comparable to the GMCs in M 31 and M 33. However, the GMC studied here shows smaller surface densities and masses than the clouds identified in Henize 2–10 and associated with super star cluster formation.

Item Type:Article
Related URLs:
URLURL TypeDescription
Testi, L.0000-0003-1859-3070
Carey, S.0000-0002-0221-6871
Menten, K. M.0000-0001-6459-0669
Noriega-Crespo, A.0000-0002-6296-8960
Additional Information:© 2010 ESO. Received 1 February 2010; Accepted 3 June 2010. Published online 30 September 2010. Based on observations made with the 14 m FCRAO telescope, the Spitzer satellite, and the Atacama Pathfinder Experiment (APEX), ESO project: 181.C-0885. APEX is a collaboration between the Max-Planck- Institut fur Radioastronomie, the European Southern Observatory, and the Onsala Space Observatory. We thank the APEX support astronomers for performing excellent service mode observations at APEX. The FCRAO observations were partially acquired by Carla Maxia. This work was partially supported by ASI-INAF contracts. Leonardo Bronfman acknowledges support from Center of Excellence in Astrophysics and Associated Technologies (PFB 06) and by FONDAP Center for Astrophysics 15010003.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Istituto Nazionale di Fisica Nucleare (INAF)UNSPECIFIED
Fondo de Investigación Avanzado en Areas Prioritarias (FONDAP)15010003
Subject Keywords:ISM: molecules; ISM: individual objects: G19.61–0.23; radio continuum: ISM; stars: formation
Record Number:CaltechAUTHORS:20101109-094302353
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Official Citation:The molecular environment of the Galactic star forming region G19.61–0.23 G. Santangelo, L. Testi, S. Leurini, C. M. Walmsley, R. Cesaroni, L. Bronfman, S. Carey, L. Gregorini, K. M. Menten, S. Molinari, A. Noriega-Crespo, L. Olmi and F. Schuller A&A 520 A50 (2010) DOI: 10.1051/0004-6361/201014177
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:20734
Deposited By: Jason Perez
Deposited On:09 Nov 2010 19:03
Last Modified:03 Oct 2019 02:14

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