Issue |
A&A
Volume 407, Number 1, August III 2003
|
|
---|---|---|
Page(s) | 225 - 235 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:20030832 | |
Published online | 17 November 2003 |
High resolution observations of the hot core in G29.96–0.02
1
University of Puerto Rico, Physics Department, PO Box 23343 University Station, San Juan, PR 00931-3343, USA
2
Istituto di Radio Astronomia, CNR Sezione di Firenze, Largo E. Fermi 5, 50125 Firenze, Italy
3
Osservatorio Astrofisico di Arcetri, INAF, Largo E. Fermi 5, 50125 Firenze, Italy e-mail: cesa@arcetri.astro.it; walmsley@arcetri.astro.it
4
Arecibo Observatory, Cornell University, HC3 Box 53995, Arecibo, PR 00612, USA e-mail: hofner@naic.edu
5
Instituto de Astronomia, Universidad Nacional Autónoma de México, Apdo. Postal 3-72, C.P. 58090, Morelia, Michoacán, Mexico e-mail: s.kurtz@astrosmo.unam.mx
6
Washburn Observatory, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706, USA e-mail: ebc@astro.wisc.edu
Corresponding author: L. Olmi, olmi@naic.edu
Received:
12
February
2003
Accepted:
21
May
2003
We present high angular resolution observations obtained with
the Owens Valley and the IRAM Plateau de Bure millimeter-wave
interferometers toward the hot core in G29.96–0.02. We observed the
ground state (6–5), (6–5), vibrationally excited ()
(6–5), and the (1–0) rotational transitions, as well as the
2.7 mm continuum emission. Our continuum maps
show evidence of a compact source barely resolved
whose diameter we estimate to be about 0.06 pc and whose emission mechanism
is dominated by thermal emission from warm dust.
Both the ground state and the
methyl cyanide lines, as well as
other serendipituosly detected
molecular transitions, arise from a compact source at the same position
as the 2.7 mm continuum emission. The observations sample the
structure and kinematics of the molecular surroundings of
the hot core and from the data we estimate a gas mass
of about
in a region with a diameter of 0.32 pc,
corresponding to an average number density of about 106 cm-3.
Our data show evidence of
both a temperature and density gradient in the hot core and its molecular
surroundings. The density gradient, in particular, is consistent with
the infalling scenario suggested by the presence of an East-West oriented
velocity gradient, which is however of opposite sign in and . We tentatively interpret the velocity gradient as associated
with infall, whereas the gradient, consistent with that
measured in by Cesaroni et al. ([CITE]), is likely to
trace a massive rotating disk.
Key words: stars: formation / radio lines: ISM / ISM: individual objects: G29.96–0.02 / ISM: molecules
© ESO, 2003
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