J/A+A/656/A101 G305 Giant Molecular Cloud II. Clump properties (Mazumdar+, 2021)
High resolution LAsMA 12CO and 13CO observation of the G305 giant molecular
cloud complex: II. Effect of feedback on clump properties.
Mazumdar P., Wyrowski F., Urquhart J.S., Colombo D., Menten K.M.,
Neupane S., Thompson M.A.
<Astron. Astrophys. 656, A101 (2021)>
=2021A&A...656A.101M 2021A&A...656A.101M (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Millimetric/submm sources ; Carbon monoxide
Keywords: submillimeter: ISM - ISM: structure - evolution -
stars: formation - methods: analytical - techniques: image processing
Abstract:
G305 star-forming complex was observed in the 3-2 lines of 12 & 13CO
to investigate the effect of feedback from the central OB stars on the
complex. The region was decomposed into clumps using dendrogram
analysis. A catalog of clump properties was created. The surface mass
densities of the clumps were plotted as a function of the incident 8um
flux. A mask of the region with 8um flux >100MJy/sr was created and
clumps were categorized based on the extent of overlap with the mask
into "mostly inside", "partly inside" & "outside". The surface mass
density distribution of each of these populations were plotted. This
was followed by comparing G305 clumps with the Galactic average taken
from the ATLASGAL and CHIMPS clumps. Finally, the cumulative
distribution functions (CDF) of the clump masses in G305 & their L/M
ratios were compared to that of the Galactic sample. The surface mass
densities of clumps showed a positive correlation with incident 8um
flux. The data did not have sufficient velocity resolution to discern
the effects of feedback on the linewidths of the clumps. The
sub-sample of clumps named "mostly inside" had the highest surface
mass densities followed by "partly -inside" and "outside" sub-samples.
These differences between the three sub-samples were shown to be
statistically significant using the KS test. The "mostly inside"
sample also showed the highest level of fragmentation compared to the
other two. These prove that clumps inside the G305 region are
triggered. The G305 clump population is also statistically different
from the Galactic average population rejecting redistribution as a
likely consequence of feedback. The CDFs of clump masses and their L/M
ratios are both flatter than the Galactic average, indicating that
feedback in G305 has triggered star formation. The collect & collapse
method is the dominant mechanism at play in G305.
Description:
Properties of clumps derived from a dendrogram analysis on the 13CO
datacube of G305 star-forming region are presented. The spatial
resolution of the datacube is 19". These properties were used to study
the effect of feedback from the OB stars at the center of G305 on the
clumps and consequently test theories of high mass star-formation.
Objects:
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RA (2000) DE Designation(s)
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13 09 30.39 -62 45 53.3 G305 = SDC G304.997+0.034
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 62 337 Clump properties of 337 clumps extracted
list.dat 107 2 List of fits datacubes
fits/* . 2 Individual fits datacubes
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [0/336] Cluster ID sequential number
5 A1 --- StrTag [lb] Hierarchical Level: l=leaf, b=branch
7- 13 F7.3 deg Xc Galactic x-coordinate in degrees
15- 20 F6.3 deg Yc Galactic y-coordinate in degrees
22- 25 F4.1 pc Rad Radius of the structure
27- 29 F3.1 km/s vrms Velocity linewidth of the clump
31- 37 F7.2 K.km.pc+2/s Lum Luminosity of the clump
39- 44 I6 Msun Mass Mass of clump
46- 50 F5.2 --- alpha Virial parameter
52- 57 I6 cm-3 nH2 H2 number density
59- 62 I4 MJy/sr F8um Average incident 8um flux on the clump
(using GLIMPSE) (1)
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Note (1): Chappell D. & Scalo J., 2001MNRAS.325....1C 2001MNRAS.325....1C,
Churchwell E., Babler B.L., Meade M.R., et al., 2009PASP..121..213C 2009PASP..121..213C.
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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 A1 --- --- [G]
2- 10 F9.5 deg GLON Galactic longitude of center (J2000)
11- 19 F9.5 deg GLAT Galactic latitude of center (J2000)
21- 23 I3 --- Nx Number of pixels along X-axis
25- 27 I3 --- Ny Number of pixels along Y-axis
29- 31 I3 --- Nz Number of pixels along Z-axis
33- 38 I6 m/s bVRAD Lower value of VRAD interval
40- 43 I4 m/s BVRAD Upper value of VRAD interval
45- 47 I3 m/s dVRAD VRAD resolution
49- 54 I6 Kibyte size Size of FITS file
56- 66 A11 --- FileName Name of FITS file, in subdirectory fits
68-107 A40 --- Title Title of the FITS file
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Acknowledgements:
Parichay Mazumdar, mazumdar.parichay(at)gmail.com
References:
Mazumdar et al., Paper I 2021A&A...650A.164M 2021A&A...650A.164M
(End) Parichay Mazumdar [MPIfR, Bonn], Patricia Vannier [CDS] 21-Sep-2021