Reversal of infall in SgrB2(M) revealed by Herschel/HIFI observations of HCN lines at THz frequencies
Journal article, 2010

Aims. To investigate the accretion and feedback processes in massive star formation, we analyze the shapes of emission lines from hot molecular cores, whose asymmetries trace infall and expansion motions. Methods. The high-mass star forming region SgrB2(M) was observed with Herschel/HIFI (HEXOS key project) in various lines of HCN and its isotopologues, complemented by APEX data. The observations are compared to spherically symmetric, centrally heated models with density power-law gradient and different velocity fields (infall or infall+expansion), using the radiative transfer code RATRAN. Results. The HCN line profiles are asymmetric, with the emission peak shifting from blue to red with increasing J and decreasing line opacity (HCN to (HCN)-C-13). This is most evident in the HCN 12-11 line at 1062 GHz. These line shapes are reproduced by a model whose velocity field changes from infall in the outer part to expansion in the inner part. Conclusions. The qualitative reproduction of the HCN lines suggests that infall dominates in the colder, outer regions, but expansion dominates in the warmer, inner regions. We are thus witnessing the onset of feedback in massive star formation, starting to reverse the infall and finally disrupting the whole molecular cloud. To obtain our result, the THz lines uniquely covered by HIFI were critically important.

cologne database

ISM:

ISM: kinematics and dynamics

star-formation

ISM: structure

b2

molecular-spectroscopy

facility

submillimeter: ISM

stars: formation

molecules

outflow

cdms

ISM: individual objects: SgrB2(M)

Author

R. Rolffs

University of Cologne

Max Planck Society

P. Schilke

University of Cologne

Max Planck Society

C. Comito

Max Planck Society

E. A. Bergin

University of Michigan

F. F. S. van der Tak

Netherlands Institute for Space Research (SRON)

D. C. Lis

California Institute of Technology (Caltech)

S. L. Qin

University of Cologne

K. M. Menten

Max Planck Society

R. Güsten

Max Planck Society

T. A. Bell

California Institute of Technology (Caltech)

G. A. Blake

California Institute of Technology (Caltech)

E. Caux

University of Toulouse

Institut National des Sciences de l'Univers

C. Ceccarelli

Laboratoire d'Astrophysique de l'Observatoire de Grenoble

J. Cernicharo

Centro de Astrobiologia (CAB)

N. R. Crockett

University of Michigan

F. Daniel

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

Centro de Astrobiologia (CAB)

M. L. Dubernet

GEPI - Galaxies, Etoiles, Physique, Instrumentation

Pierre and Marie Curie University (UPMC)

M. Emprechtinger

California Institute of Technology (Caltech)

P. Encrenaz

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

M. Gerin

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

T. F. Giesen

University of Cologne

J. R. Goicoechea

Centro de Astrobiologia (CAB)

P. F. Goldsmith

Jet Propulsion Laboratory, California Institute of Technology

H. Gupta

Jet Propulsion Laboratory, California Institute of Technology

E. Herbst

Ohio State University

C. Joblin

University of Toulouse

Institut National des Sciences de l'Univers

D. Johnstone

National Research Council Canada

W. D. Langer

Jet Propulsion Laboratory, California Institute of Technology

W. D. Latter

California Institute of Technology (Caltech)

S. D. Lord

California Institute of Technology (Caltech)

S. Maret

Laboratoire d'Astrophysique de l'Observatoire de Grenoble

P. G. Martin

Canadian Institute for Theoretical Astrophysics

G. J. Melnick

Harvard-Smithsonian Center for Astrophysics

P. Morris

California Institute of Technology (Caltech)

Holger Muller

University of Cologne

J. A. Murphy

Maynooth University

V. Ossenkopf

Netherlands Institute for Space Research (SRON)

University of Cologne

J. C. Pearson

Jet Propulsion Laboratory, California Institute of Technology

M. Perault

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

T. G. Phillips

California Institute of Technology (Caltech)

R. Plume

University of Calgary

S. Schlemmer

University of Cologne

J. Stutzki

University of Cologne

N. Trappe

Maynooth University

C. Vastel

University of Toulouse

Institut National des Sciences de l'Univers

S. Wang

University of Michigan

H. W. Yorke

Jet Propulsion Laboratory, California Institute of Technology

S. Yu

Jet Propulsion Laboratory, California Institute of Technology

J. Zmuidzinas

California Institute of Technology (Caltech)

M. C. Diez-Gonzalez

Yebes Observatory

R. Bachiller

Yebes Observatory

J. Martin-Pintado

CSIC - Instituto de Estructura de la Materia (IEM)

W. Baechtold

Swiss Federal Institute of Technology in Zürich (ETH)

Michael Olberg

Chalmers, Earth and Space Sciences, Onsala Space Observatory

L. H. Nordh

Stockholm University

John Gill

Jet Propulsion Laboratory, California Institute of Technology

Goutam Chattopadhyay

Jet Propulsion Laboratory, California Institute of Technology

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 521 1 Article Number: L46 - L46

Subject Categories

Astronomy, Astrophysics and Cosmology

DOI

10.1051/0004-6361/201015106

More information

Latest update

4/30/2020