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H_2D^+ in the High-mass Star-forming Region Cygnus X

Pillai, T. and Caselli, P. and Kauffmann, J. and Zhang, Q. and Thompson, M. A. and Lis, D. C. (2012) H_2D^+ in the High-mass Star-forming Region Cygnus X. Astrophysical Journal, 751 (2). Art. No. 135. ISSN 0004-637X. doi:10.1088/0004-637X/751/2/135.

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H_2D^+ is a primary ion that dominates the gas-phase chemistry of cold dense gas. Therefore, it is hailed as a unique tool in probing the earliest, prestellar phase of star formation. Observationally, its abundance and distribution is, however, just beginning to be understood in low-mass prestellar and cluster-forming cores. In high-mass star-forming regions, H_2D^+ has been detected only in two cores, and its spatial distribution remains unknown. Here, we present the first map of the ortho-H_2D^+J_(k^+,k^-) = 1_(1,0) → 1_(1,1) and N_2H^+ 4-3 transition in the DR21 filament of Cygnus X with the James Clerk Maxwell Telescope, and N_2D^+ 3-2 and dust continuum with the Submillimeter Array. We have discovered five very extended (≤34, 000 AU diameter) weak structures in H2D+ in the vicinity of, but distinctly offset from, embedded protostars. More surprisingly, the H_2D^+ peak is not associated with either a dust continuum or N_2D^+ peak. We have therefore uncovered extended massive cold dense gas that was undetected with previous molecular line and dust continuum surveys of the region. This work also shows that our picture of the structure of cores is too simplistic for cluster-forming cores and needs to be refined: neither dust continuum with existing capabilities nor emission in tracers like N_2D^+ can provide a complete census of the total prestellar gas in such regions. Sensitive H_2D^+ mapping of the entire DR21 filament is likely to discover more of such cold quiescent gas reservoirs in an otherwise active high-mass star-forming region.

Item Type:Article
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URLURL TypeDescription Paper
Caselli, P.0000-0003-1481-7911
Lis, D. C.0000-0002-0500-4700
Additional Information:© 2012 American Astronomical Society. Received 2012 January 23; accepted 2012 March 30; published 2012 May 15. We are grateful to Dr. Iain Coulson and the JCMT staff for their kind support with observations and data handling. The James Clerk Maxwell Telescope is operated by The Joint Astronomy Centre on behalf of the Science and Technology Facilities Council of the United Kingdom, the Netherlands Organisation for Scientific Research, and the National Research Council of Canada. The JCMT data were obtained under the program ID M07BU14. This research was supported by an appointment of J.K. to the NASA Postdoctoral Program at the Jet Propulsion Laboratory, administered by Oak Ridge Associated Universities through a contract with NASA. It was executed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. T.P. acknowledges support from the Combined Array for Research in Millimeter-wave Astronomy (CARMA), which is supported by the National Science Foundation through grant AST 05-40399. T.P. acknowledges support from the SMA Fellowship Program while working on this project. A significant part of this work was done at the Center for Astrophysics, MA, USA. Facilities: JCMT(HARP), SMA, Spitzer (IRAC)
Funding AgencyGrant Number
NASA Postdoctoral ProgramUNSPECIFIED
Combined Array for Research in Millimeter-wave Astronomy (CARMA)UNSPECIFIED
NSFAST 05-40399
Submillimeter Array Postdoctoral FellowshipUNSPECIFIED
Subject Keywords: ISM: abundances; ISM: clouds; ISM: individual objects (Cygnus X); ISM: molecules; ISM: structure; radio lines: ISM; stars: formation
Issue or Number:2
Record Number:CaltechAUTHORS:20120620-135956437
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Official Citation:H2D+ in the High-mass Star-forming Region Cygnus X T. Pillai et al. 2012 ApJ 751 135
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:31991
Deposited By: Ruth Sustaita
Deposited On:20 Jun 2012 21:23
Last Modified:09 Nov 2021 20:02

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