J/A+A/660/A56 NGC 6334 maps and CO velocity cubes (Arzoumanian+, 2022)
Velocity structure of the 50 pc long NGC 6334 filamentary cloud.
Hints of multiple compressions and their impact on the cloud properties.
Arzoumanian D., Russeil D., Zavagno A., Chun-yuan Chen M., Andre P.,
Inutsuka S.-I., Misugi Y., Sanchez-Monge A., Schilke P., Men'shchikov A.,
Kohno M.
<Astron. Astrophys., 660, A56 (2022)>
=2022A&A...660A..56A 2022A&A...660A..56A (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium ; Molecular clouds ; Millimetric/submm sources
Keywords: stars: formation - ISM: clouds - ISM: kinematics and dynamics -
ISM: structure - submillimeter: ISM
Abstract:
The interstellar medium is observed to be organized in filamentary
structures, and in neutral (HI) and ionized (HII) bubbles. The
expanding nature of these bubbles shapes the surrounding medium and
possibly plays a role in the formation and evolution of the
interstellar filaments. The impact of the expansion of these bubbles
on the interstellar medium is not well understood.
Our aim is to describe the kinematics of a filamentary molecular cloud
forming high-mass stars and hosting multiple HII regions in order to
study the possible environmental impact on the properties of molecular
filaments.
We present APEX 13CO and C18O(2-1) mapping observations of the
10x50pc NGC 6334 molecular cloud complex. We investigated the gas
velocity structure along and across the 50pc long cloud and toward
velocity-coherent filaments (VCFs).
The NGC 6334 complex is observed to have a coherent velocity structure
smoothly varying by ∼5km/s over its 50 pc elongation parallel to the
Galactic plane. We identify a sample of 75 VCFs in the C18O(2-1)
position-position-velocity cube and present the properties of 47 VCFs
with a length ≥1pc (five beams). We measure a large number of
velocity gradients along the VCFs. The amplitudes of these velocity
gradients and the velocity dispersion measured along the crests
increase with the column density of the VCFs. We derive the column
density and velocity power spectra of the VCFs. These power spectra
are well represented with power laws showing similar slopes for the
two quantities (with a mean of about -2), although some differ by up
to a factor of 2. The position velocity diagrams perpendicular to
three VCFs (selected from different physical environments) show the
V-shaped velocity pattern corresponding to a bent structure in
velocity space with the filament at the tip of the V surrounded by an
extended structure connected to it with a velocity gradient. This
velocity structure is qualitatively similar to that resulting from
numerical simulations of filament formation from large-scale
compression from propagating shock fronts.In addition, the radial
profiles perpendicular to these VCFs hint to small-scale internal
impacts from neighboring HII bubbles on two of them, while the third
is mostly unaffected.
The observed opposite curvature in velocity space (V- and A-shaped)
toward the VCFs points to various origins of large-scale external
compressions from propagating HI bubbles. This suggests the plausible
importance of multiple HI compressions, separated in space and time,
in the formation and evolution of molecular clouds and their star
formation history. These atomic compressions due to past and distant
star formation events are complemented by the impact of HII bubbles
from present time and local star formation activity.
Description:
Column density and dust temperature maps as derived from Herschel
Space Observatory data taken as part of the HOBYS key project (Motte
et al., 2010A&A...518L..77M 2010A&A...518L..77M) of the NGC 6334 high-mass star-forming
molecular cloud.
Position-position-velocity cubes of the 13CO(2-1) and C18O(2-1)
molecular line emission towards NGC 6334 observed with the APEX
telescope (Zernickel, 2015, PhD thesis, I. Physikalisches Institut der
Universitaet zu Koeln, 2015PhDT........12Z 2015PhDT........12Z).
Objects:
--------------------------------------------------------------
RA (2000) DE Designation(s)
--------------------------------------------------------------
17 20 50.9 -36 06 54 NGC 6334 = NAME Cat's Paw Nebula
--------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 202 5 List of fits files
fits/* . 5 Individual fits files
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 I4 --- Nx Number of pixels along X-axis
25- 27 I3 --- Ny Number of pixels along Y-axis
29- 31 I3 --- Nz ? Number of slices for the datacubes
33- 40 F8.1 m/s bVELO-LSR ? Lower value of VELO-LSR for the datacubes
42- 48 F7.1 m/s BVELO-LSR ? Upper value of VELO-LSR for the datacubes
50- 56 F7.3 m/s dVELO-LSR ? VELO-LSR resolution for the datacubes
58- 63 I6 Kibyte size Size of FITS file
65-110 A46 --- FileName Name of FITS file, in subdirectory fits
112-202 A91 --- Title Title of the FITS file
--------------------------------------------------------------------------------
Acknowledgements:
Doris Arzoumanian, doris.arzou(at)gmail.com
(End) Patricia Vannier [CDS] 23-Sep-2022