2010A&A...521L..46R


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.15CEST04:52:58

2010A&A...521L..46R - Astronomy and Astrophysics, volume 521, L46-46 (2010/10-1)

Reversal of infall in Sgr B2(M) revealed by Herschel/HIFI observations of HCN lines at THz frequencies.

ROLFFS R., SCHILKE P., COMITO C., BERGIN E.A., VAN DER TAK F.F.S., LIS D.C., QIN S.-L., MENTEN K.M., GUESTEN R., BELL T.A., BLAKE G.A., CAUX E., CECCARELLI C., CERNICHARO J., CROCKETT N.R., DANIEL F., DUBERNET M.-L., EMPRECHTINGER M., ENCRENAZ P., GERIN M., GIESEN T.F., GOICOECHEA J.R., GOLDSMITH P.F., GUPTA H., HERBST E., JOBLIN C., JOHNSTONE D., LANGER W.D., LATTER W.D., LORD S.D., MARET S., MARTIN P.G., MELNICK G.J., MORRIS P., MUELLER H.S.P., MURPHY J.A., OSSENKOPF V., PEARSON J.C., PERAULT M., PHILLIPS T.G., PLUME R., SCHLEMMER S., STUTZKI J., TRAPPE N., VASTEL C., WANG S., YORKE H.W., YU S., ZMUIDZINAS J., DIEZ-GONZALEZ M.C., BACHILLER R., MARTIN-PINTADO J., BAECHTOLD W., OLBERG M., NORDH L.H., GILL J.J. and CHATTOPADHYAY G.

Abstract (from CDS):

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. 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. The HCN line profiles are asymmetric, with the emission peak shifting from blue to red with increasing J and decreasing line opacity (HCN to H13CN). This is most evident in the HCN 12-11 line at 1062GHz. These line shapes are reproduced by a model whose velocity field changes from infall in the outer part to expansion in the inner part. 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.

Abstract Copyright:

Journal keyword(s): stars: formation - ISM: kinematics and dynamics - ISM: structure - ISM: molecules - ISM: individual objects: SgrB2(M) - submillimeter: ISM

Simbad objects: 3

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Number of rows : 3

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11620 0
2 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 1921 1
3 NAME Sgr B2 Main Rad 17 47 20.5 -28 23 06           ~ 333 1

    Equat.    Gal    SGal    Ecl

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2020.08.15-04:52:58

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