J/A+A/572/A63 Intensity maps in the star-forming complex W33 (Immer+, 2014)
Diversity of chemistry and excitation conditions in the high-mass star forming
complex W33.
Immer K., Galvan-Madrid R., Konig C., Liu H.B., Menten K.M.
<Astron. Astrophys. 572, A63 (2014)>
=2014A&A...572A..63I 2014A&A...572A..63I
ADC_Keywords: Molecular clouds ; Milky Way ; Interferometry ;
Interstellar medium ; Millimetric/submm sources
Keywords: stars: formation - astrochemistry - stars: protostars -
ISM: individual objects: W33 - submillimeter: ISM - ISM: molecules
Abstract:
The object W33 is a giant molecular cloud that contains star forming
regions at various evolutionary stages from quiescent clumps to
developed HII regions. Since its star forming regions are located at
the same distance and the primary material of the birth clouds is
probably similar, we conducted a comparative chemical study to trace
the chemical footprint of the different phases of evolution. We
observed six clumps in W33 with the Atacama Pathfinder Experiment
(APEX) telescope at 280GHz and the Submillimeter Array (SMA) at
230GHz. We detected 27 transitions of 10 different molecules in the
APEX data and 52 transitions of 16 different molecules in the SMA
data. The chemistry on scales larger than ∼0.2pc, which are traced by
the APEX data, becomes more complex and diverse the more evolved the
star forming region is. On smaller scales traced by the SMA data, the
chemical complexity and diversity increase up to the hot core stage.
In the HII region phase, the SMA spectra resemble the spectra of the
protostellar phase. Either these more complex molecules are destroyed
or their emission is not compact enough to be detected with the SMA.
Synthetic spectra modelling of the H2CO transitions, as detected
with the APEX telescope, shows that both a warm and a cold component
are needed to obtain a good fit to the emission for all sources except
for W33 Main1. The temperatures and column densities of the two
components increase during the evolution of the star forming regions.
The integrated intensity ratios N2H+(3-2)/CS(6-5) and
N2H+(3-2)/H2CO(42,2-32,1) show clear trends as a function of
evolutionary stage, luminosity, luminosity-to-mass ratio, and H2
peak column density of the clumps and might be usable as chemical
clocks.
Description:
Integrated intensity maps of line and continuum emission at ∼230 and
∼270GHz, taken with the SMA and the APEX telescope, respectively. The
emission was observed towards the six clumps W33 Main1, W33 A1,
W33 B1, W33 B, W33 A, and W33 Main in the high-mass star forming
complex W33. All maps are in equatorial coordinates. The flux of the
APEX maps is given in K.km/s. The flux of the SMA continuum maps is
given in Jy/beam and the flux of the SMA line maps is given in Jy/beam
km/s.
Objects:
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RA (ICRS) DE Designation(s)
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18 14 39.059 -17 52 02.72 W33A = W 33A
18 14 36.087 -17 55 04.95 W33A1 = W 33A1
18 13 54.368 -18 01 51.92 W33B = W 33B
18 14 07.144 -18 00 45.10 W33B1 = W 33B1
18 14 13.531 -17 55 47.47 W33M = W33 Main
18 14 25.021 -17 53 58.13 W33M1 = W33 Main1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 184 164 List of FITS files
fits/* . 164 Individual FITS files
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 22 F3.1 arcsec/pix scale [0.2/6] Scale of the image
24- 27 I4 --- Nx [18/1024] Number of pixels along X-axis
29- 32 I4 --- Ny [16/1024] Number of pixels along Y-axis
34- 42 F9.5 GHz Freq [216/347] Frequency of map
46- 49 I4 Kibyte size [8/4171] Size of FITS file
51- 76 A26 --- FileName Name of FITS file, in subdirectory fits
78-184 A107 --- Title Title of the file
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Acknowledgements:
Katharina Immer, kimmer(at)eso.org
(End) Patricia Vannier [CDS] 03-Oct-2014