J/A+A/664/A26 W43-MM2&MM3 ministarburst ALMA data (Pouteau+, 2022)
ALMA-IMF. III. Investigating the origin of stellar masses:
top-heavy core mass function in the W43-MM2&MM3 mini-starburst.
Pouteau Y., Motte F., Nony T., Galvan-Madrid R., Men'shchikov A.,
Bontemps S., Robitaille J.-F., Louvet F., Ginsburg A., Herpin F.,
Lopez-Sepulcre A., Dell'Ova P., Gusdorf A., Sanhueza P., Stutz A.M.,
Brouillet N., Thomasson B., Armante M., Baug T., Busquet G., Csengeri T.,
Cunningham N., Fernandez-Lopez M., Liu H.-L., Olguin F., Towner A.P.M.,
Bally J., Braine J., Bronfman L., Joncour I., Gonzalez M., Hennebelle P.,
Lu X., Menten K.M., Moraux E., Tatematsu K., Walker D., Whitworth A.P.
<Astron. Astrophys. 664, A26 (2022)>
=2022A&A...664A..26P 2022A&A...664A..26P (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Millimetric/submm sources
Keywords: stars: formation - stars: massive - ISM: clouds - submillimeter: ISM -
dust, extinction - stars: luminosity function - mass function
Abstract:
The processes that determine the stellar initial mass function (IMF)
and its origin are critical unsolved problems, with profound
implications for many areas of astrophysics. The W43-MM2&MM3
mini-starburst ridge hosts a rich, young protocluster, from which one
can test the current paradigm on the IMF origin. The ALMA-IMF Large
Program observed the W43-MM2&MM3 ridge, whose 1.3mm and 3mm ALMA 12m
array continuum images reach a ∼2500au spatial resolution. We used
both the best-sensitivity and the line-free ALMA-IMF images, reduced
the noise with the multi-resolution segmentation technique MnGSeg, and
derived the most complete and most robust core catalog possible. Using
two different extraction software packages, getsf and GExt2D, we
identified ∼200 compact sources, whose ∼100 common sources have on
average fluxes consistent to within 30%. We filtered sources with
non-negligible free-free contamination and corrected fluxes from line
contamination, resulting in a W43-MM2&MM3 catalog of 205 getsf cores.
With a median deconvolved FWHM size of 3400au, core masses range from
∼0.1M_☉ to ∼70M☉ and the getsf catalog is 90% complete down
to 0.8M☉.
The high-mass end of the core mass function (CMF) of W43-MM2&MM3 is
top-heavy compared to the canonical IMF. Fitting the cumulative CMF
with a single power law of the form N(>logM)∝Malpha, we
measured alpha=-0.95±0.04, compared to the canonical alpha=-1.35
Salpeter IMF slope. The slope of the CMF is robust with respect to map
processing, extraction software package, and reasonable variations in
the assumptions taken to estimate core masses. We explore several
assumptions on how cores transfer their mass to stars (assuming a mass
conversion efficiency) and sub-fragment (defining a core fragment mass
function) to predict the IMF resulting from the W43-MM2&MM3 CMF. While
core mass growth should flatten the high-mass end of the resulting
IMF, core fragmentation could steepen it.
In stark contrast to the commonly accepted paradigm, our result argues
against the universality of the CMF shape. More robust functions of
the star-formation efficiency and core sub-fragmentation are required
to better predict the resulting IMF, here suggested to remain
top-heavy at the end of the star-formation phase. If confirmed, the
IMFs emerging from starburst events could inherit their top-heavy
shape from their parental CMFs, challenging the IMF universality.
Description:
Derived properties of the 205 cores extracted by getsf.
Objects:
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RA (J2000) DE Designation(s)
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18 47 36.6 -02 00 54 [MSL2003] W43-MM2 = AGAL G030.703-00.067
18 47 41.7 -02 00 26 [MSL2003] W43-MM3 = [MSL2003] W43-MM3
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablee1.dat 134 208 ALMA catalogue, detections
tablee2.dat 54 205 ALMA catalogue, derived parameters
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See also:
J/A+A/662/A9 : 15 dense molecular cloud regions ALMA images (Ginsburg+, 2022)
Byte-by-byte Description of file: tablee1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/296] Core identifier of getsf
5- 22 A18 --- Name Core name (HHMMSS.ss+DMMSS.ss),
W43-MM2&3_ALMAIMF HHMMSS.ss+DMMSS.ss
24- 25 I2 h RAh Right ascension (J2000)
27- 28 I2 min RAm Right ascension (J2000)
30- 34 F5.2 s RAs Right ascension (J2000)
36 A1 - DE- Declination sign (J2000)
37 I1 deg DEd Declination (J2000)
39- 40 I2 arcmin DEm Declination (J2000)
42- 46 F5.2 arcsec DEs Declination (J2000)
48- 50 F3.1 arcsec afwhm1.3 FWHM major axis, at 1.3mm
52- 54 F3.1 arcsec bfwhm1.3 FWHM minor axis, at 1.3mm
56- 58 I3 deg PA1.3 Position angle, at 1.3mm (North to East)
60- 65 F6.2 mJy/beam Speak1.3 Peak flux, at 1.3mm
67- 70 F4.2 mJy/beam e_Speak1.3 Peak flux error, at 1.3mm
72- 77 F6.2 mJy Sint1.3 Integrated flux, at 1.3mm
79- 82 F4.2 mJy e_Sint1.3 Integrated flux error, at 1.3mm
84- 86 F3.1 arcsec afwhm3 ?=- FWHM major axis, at 3mm
88- 90 F3.1 arcsec bfwhm3 ?=- FWHM minor axis, at 3mm
92- 94 I3 deg PA3 ?=- Position angle, at 3mm (North to East)
96- 97 A2 --- l_Speak3 [≤ ] Limit flag on Speak3
98-102 F5.3 mJy/beam Speak3 Peak flux, at 3mm
104-107 F4.2 mJy/beam e_Speak3 ?=- Peak flux error, at 3mm
109-110 A2 --- l_Sint3 [≤ ] Limit flag on Sint3
111-116 F6.3 mJy Sint3 Integrated flux, at 3mm
118-121 F4.2 mJy e_Sint3 ?=- Integrated flux error, at 3mm
123-124 A2 --- Tagd [* -] Tag for sources also detected by
GExt2D and that may have a 1.3mm flux less
than a factor of two compared to getsf
126-134 A9 --- Com Tag for partially or almost fully
contaminated sources
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Byte-by-byte Description of file: tablee2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/296] Core identifier of getsf
5- 22 A18 --- Name Core name (HHMMSS.ss+DMMSS.ss),
W43-MM2&3_ALMAIMF HHMMSS.ss+DMMSS.ss
24- 27 I4 au FWHMdec1.3 Deconvolved physical core size, at 1.3mm
29- 32 F4.1 Msun Mass Core dust mass, at 1.3mm
34- 37 F4.1 Msun e_Mass Core dust mass error, at 1.3mm
39- 42 F4.1 K Tdust Dust temperature of the core
44- 47 F4.1 K e_Tdust Dust temperature error of the core
49- 54 F6.2 10+6cm-3 nH2 Volume density of the core
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Acknowledgements:
Yohan Pouteau, yohan.pouteau(at)univ-grenoble-alpes.fr
References:
Motte et al., Paper I 2022A&A...662A...8M 2022A&A...662A...8M
Ginsburg et al., Paper II 2022A&A...662A...9G 2022A&A...662A...9G, Cat. J/A+A/662/A9
(End) Patricia Vannier [CDS] 13-Mar-2022