J/ApJ/916/45 Core mass function across galactic env. III. (O'Neill+, 2021)
The core mass function across galactic environments.
III. Massive protoclusters.
O'Neill T.J., Cosentino G., Tan J.C., Cheng Yu, Liu M.
<Astrophys. J., 916, 45 (2021)>
=2021ApJ...916...45O 2021ApJ...916...45O
ADC_Keywords: Surveys; Milky Way; Millimetric/submm sources;
Star Forming Region; Infrared sources
Keywords: Star formation ; Interstellar medium
Abstract:
The stellar initial mass function (IMF) is fundamental for many areas
of astrophysics, but its origin remains poorly understood. It may be
inherited from the core mass function (CMF) or arise as a result of
more chaotic, competitive accretion. Dense, gravitationally bound
cores are seen in molecular clouds and some observations have
suggested that the CMF is similar in shape to the IMF, though
translated to higher masses by a factor of ∼3. Here we measure the CMF
in 28 dense clumps within 3.5kpc that are likely to be central regions
of massive protoclusters, observed via 1.3mm dust continuum emission
by the ALMAGAL project. We identify 222 cores using the dendrogram
algorithm with masses ranging from 0.04 to 252M☉. We apply
completeness corrections for flux and number recovery, estimated from
core insertion and recovery experiments. At higher masses, the final
derived CMF is well described by a single power law of the form
dN/d.logM∝M-α with α∼0.94±0.08. However, we
find evidence of a break in this power-law behavior between ∼5 and
15M☉, which is, to our knowledge, the first time such a break
has been found in distant (≳1kpc) regions by the Atacama Large
Millimeter/submillimeter Array. We compare this massive protocluster
CMF with those derived using the same methods in the G286 protocluster
and a sample of infrared dark clouds. The massive protocluster CMF is
significantly different, i.e., containing more massive cores, which is
a potential indication of the role of environment on the CMF and IMF.
Description:
We selected sources from the ALMA Cycle 7 project ALMAGAL (ALMA
Evolutionary Study of High Mass Protocluster Formation in the Galaxy;
PI: S. Molinari). This survey was designed to observe continuum and
line emission near 1.4mm from ≳1000 high-mass Galactic clumps
(d<7.5kpc and Mcl>500M☉) identified by the Herschel Hi-GAL
survey (Elia+ 2017, J/MNRAS/471/100). We limited our analysis to
sources within 3.5kpc that had 12m-array observations delivered to the
ALMA archive by May 2020. This yielded a sample of 28 sources.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 81 28 Overview of clump sample
tablea1.dat 69 222 Estimated physical parameters for cores
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See also:
J/A+A/291/943 : Protostellar cores (Ossenkopf+, 1994)
J/ApJ/428/693 : Rosette Nebula & Maddalena Cloud structures (Williams+ 1994)
J/A+A/462/L17 : Dense cores in interstellar molecular clouds (Alves+, 2007)
J/A+A/545/A51 : 1.4mm & 3mm interferometry of IRAS 19410+2336 (Rodon+, 2012)
J/A+A/584/A91 : Dense cores in Aquila from Herschel (Konyves+, 2015)
J/MNRAS/471/100 : Hi-GAL compact source catalog. -71.0<l<67.0 (Elia+, 2017)
J/ApJ/862/105 : Core mass function across Gal. env. II. IRDCs (Liu+, 2018)
J/ApJ/886/102 : ALMA obs. of dark high-mass clumps (ASHES) (Sanhueza+, 2019)
J/A+A/632/A83 : NGC 6334 filament with ALMA (Shimajiri+, 2019)
J/ApJ/894/L14 : ALMA obs. of massive clouds in the CMZ (Lu+, 2020)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Identifier (GLLL.ll)
9- 25 A17 --- ALMA ALMA ID
27- 31 I5 --- HiID [9393/55038] Hi-GAL ID from
Elia+ 2017, J/MNRAS/471/100
( in Simbad)
33- 41 F9.5 deg GLON [18.3/346.4] Galactic longitude
43- 50 F8.5 deg GLAT [-1.63/1.05] Galactic latitude
52- 55 F4.2 kpc Dist [0.76/3.5] Distance
57- 60 F4.2 pc Rcl [0.03/0.24] Clump radius (1)
62- 65 I4 Msun Mcl [26/3021] Clump mass (1)
67- 71 F5.2 g/cm2 Sigcl [0.39/10.67] Clump mass surface density,
Σcl (1)
73 I1 --- Type [1/2] Clump type (1=prestellar clump;
2=protostellar clump) (1)
75- 78 F4.2 mJy/beam rms [0.13/1.38] rms noise
80- 81 I2 --- Nc [2/33] Number of dendrogram-identified cores
in the clump
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Note (1): The radius, mass, Σcl, and type were derived
by Elia+ 2017, J/MNRAS/471/100, where type is the evolutionary
classification of the clump in which 1 represents a prestellar clump
and 2 represents a protostellar clump.
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Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Clump identifier as in Table 1 (GLLL.ll)
8- 10 A3 --- Core Core identifier within clump (c1-c33)
12- 21 F10.6 deg GLON [18.297/346.4] Galactic longitude
23- 31 F9.6 deg GLAT [-1.63/1.05] Galactic latitude
33- 38 F6.2 mJy/beam Ipeak [0.99/381.73] Peak intensity
40- 44 F5.2 mJy Snu [0.75/90.05] Flux density
46- 51 F6.2 Msun Mraw [0.04/251.84] Raw, uncorrected core mass
53- 58 F6.2 Msun Mass [0.07/277.1] Core mass estimate after
flux correction (1)
60- 63 F4.2 cpc Rad [0.18/4.44] Core radius
65- 69 F5.2 g/cm2 Sigma [0.25/30.5] Mean core mass surface density
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Note (1): Mass is Mraw multiplied by the value of fflux appropriate for Mass.
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History:
From electronic version of the journal
References:
Cheng et al. Paper I. 2018ApJ...853..160C 2018ApJ...853..160C
Liu et al. Paper II. 2018ApJ...862..105L 2018ApJ...862..105L Cat. J/ApJ/862/105
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-Dec-2022