J/A+A/696/A149 ALMAGAL. I. Target clumps properties (Molinari+, 2025)
ALMAGAL. I. The ALMA evolutionary study of high mass protocluster formation in
the Galaxy. Presentation of the survey and early results.
Molinari S., Schilke P., Battersby C., Ho P.T.P., Sanchez-Monge A.,
Traficante A., Jones B., Beltran M.T., Beuther H., Fuller G.A., Zhang Q.,
Klessen R.S., Walch S., Tang Y.-W., Benedettini M., Elia D., Coletta A.,
Mininni C., Schisano E., Avison A., Law C.Y., Nucara A., Soler J.D.,
Stroud G., Wallace J., Wells M.R.A., Ahmadi A., Brogan C.L., Hunter T.R.,
Liu S.-Y., Pezzuto S., Su Y.-N., Zimmermann B., Zhang T., Wyrowski F.,
De Angelis F., Liu S., Clarke S.D., Fontani F., Klaassen P.D., Koch P.,
Johnston K.G., Lebreuilly U., Liu T., Lumsden S.L., Moeller T.,
Moscadelli L., Kuiper R., Lis D., Peretto N., Pfalzner S., Rigby A.J.,
Sanhueza P., Rygl K.L.J., van der Tak F., Zinnecker H., Amaral F., Bally J.,
Bronfman L., Cesaroni R., Goh K., Hoare M.G., Hatchfield P., Hennebelle P.,
Henning T., Kim K.T., Kim W.-J., Maud L., Merello M., Nakamura F., Plume R.,
Qin S.-L., Svoboda B., Testi L., Veena V.S., Walker D.
<Astron. Astrophys. 696, A149 (2025)>
=2025A&A...696A.149M 2025A&A...696A.149M (SIMBAD/NED BibCode)
ADC_Keywords: Infrared sources ; Interferometry ; Millimetric/submm sources
Keywords: star formation - stars: protostars - ISM: clouds - evolution -
HII regions - submillimeter: ISM
Abstract:
A large fraction of stars form in clusters containing high-mass stars,
which subsequently influences the local and galaxy-wide environment.
Fundamental questions about the physics responsible for fragmenting
molecular parsec-scale clumps into cores of a few thousand
astronomical units (au) are still open, that only a statistically
significant investigation with ALMA is able to address; for instance:
the identification of the dominant agents that determine the core
demographics, mass, and spatial distribution as a function of the
physical properties of the hosting clumps, their evolutionary stage
and the different Galactic environments in which they reside. The
extent to which fragmentation is driven by clumps dynamics or mass
transport in filaments also remains elusive.
With the ALMAGAL project, we observed the 1.38mm continuum and lines
toward more than 1000 dense clumps in our Galaxy, with M≥500M☉,
{SIGMA}≥0.1g/cm2 and d≤7.5 kiloparsec (kpc). Two different
combinations of ALMA Compact Array (ACA) and 12-m array setups were
used to deliver a minimum resolution of ∼1000 au over the entire
sample distance range. The sample covers all evolutionary stages from
infrared dark clouds (IRDCs) to HII regions from the tip of the
Galactic bar to the outskirts of the Galaxy. With a continuum
sensitivity of 0.1mJy, ALMAGAL enables a complete study of the
clump-to-core fragmentation process down to M∼0.3M☉ across the
Galaxy. The spectral setup includes several molecular lines to trace
the multiscale physics and dynamics of gas, notably CH3CN, H2CO,
SiO, CH3OH, DCN, HC3N, and SO, among others.
We present an initial overview of the observations and the early
science product and results produced in the ALMAGAL Consortium, with a
first characterization of the morphological properties of the
continuum emission detected above 5σ in our fields. We used
"perimeter-versus-area" and convex hull-versus-area metrics to
classify the different morphologies. We find that more extended and
morphologically complex (significantly departing from circular or
generally convex) shapes are found toward clumps that are relatively
more evolved and have higher surface densities.
ALMAGAL is poised to serve as a game-changer for a number of specific
issues in star formation: clump-to-core fragmentation processes,
demographics of cores, core and clump gas chemistry and dynamics,
infall and outflow dynamics, and disk detections. Many of these issues
will be covered in the first generation of papers that closely follow
on the present publication.
Description:
Physical parameters and millimeter continuum morphological descriptors
for the 1013 dense clumps observed with the ALMAGAL Large Program. We
observed 1.38mm continuum and lines toward more than 1013 dense clumps
in our Galaxy with M>500 solar masses, surface densities>0.1g/cm2
and d<7.5kpc. Two different combinations of ALMA Compact Array (ACA)
and 12-m array setups were used to deliver a minimum resolution of
around 1000 au over the entire sample distance range. The sample
covers all evolutionary stages from infrared dark clouds (IRDCs) to
HII regions from the Galactic Bar's tip to the outskirts of the
Galaxy. With a continuum sensitivity of 0.1mJy ALMAGAL enables a
complete study of the clump-to-core fragmentation process down to
M∼0.3 solar masses Galaxy-wide. The spectral setup includes several
molecular lines to trace the multiscale physics and dynamics of gas,
notably CH3CN, H2CO, SiO, CH3OH, DCN, HC3N, SO, among others.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 185 1013 Targets physical parameters
table2.dat 29 1013 Morphological parameters of the 1.38mm emission
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See also:
J/A+A/696/A151 : ALMAGAL III. Compact source catalog (Coletta+, 2024)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Num [1/1013] Target clump running number
6- 22 A17 --- Name ALMAGAL target name (AGLLL.llll+B.bbbb)
24- 44 A21 --- OrigName Original target name
46- 66 A21 --- IntID Target name in ALMA archive (internal ID)
68- 77 F10.6 deg GLON Galactic Longitude
79- 87 F9.6 deg GLAT Galactic Latitude
89 A1 --- subflag [n/f] subsample flag (near/far)
91- 96 F6.1 km/s Vlsr LSR velocity of target
98-102 I5 pc Dist Heliocentric distance
104-107 I4 pc e_Dist Uncertainty on distance
109-114 I6 Msun Mass ? Target clump mass (from Hi-GAL)
116-119 I4 Msun e_Mass ? Uncertainty on target clump mass
121-126 I6 Lsun Lum ? Target clump luminosity (from Hi-GAL)
128-132 I5 Lsun e_Lum ?=- Uncertainty on target clump luminosity
134-139 F6.1 K Tdust ? Clump dust temperature (from Hi-GAL)
141-146 F6.1 K Tbol ? Clump bolometric temperature
148-153 F6.2 g/cm2 Sdens ? Clump surface density (from Hi-GAL)
155-156 A2 --- Ecl Evolutionary Class (Urquhart et al.,
2022MNRAS.510.3389U 2022MNRAS.510.3389U,
Cat. J/MNRAS/510/3389) (1)
158-185 A28 --- Flags Source data flags (2)
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Note (1): Meaning of Ecl as follows:
Q = Quiescent
P = Protostellar
Y = Young Stellar Object
H = HII region
na = cases where the methodology failed to identify a specific class
Note (2): Meaning of flags as follows:
-kda_defnear = Source originally set at FAR kinematic distance solution by
Mege et al. (2021A&A...646A..74M 2021A&A...646A..74M, Cat. J/A+A/646/A74) in
absence of any KDA discriminator. In this work the NEAR
distance decision is instead adopted for these sources, for
consistency with the approach followed for the sources from
the RMS sample.
-V7 = The new ALMAGAL-based Vlsr differs from the original by more
than 7km/s
-D500 = The new ALMAGAL-based distance differs from the original by
more than 500pc.
-Dn2f = The new distance determined from the Vlsr of ALMAGAL dense
tracer lines, switches this source from the NEAR to the FAR
sample. As originally belonging to the NEAR sample it was
observed with a maximum 0.3 arcsec resolution, therefore now
resulting in a sub-optimal linear resolution.
-Df2n = The new distance determined from the Vlsr of ALMAGAL dense
tracer lines, switches this source from the FAR to the NEAR
sample. As originally belonging to the FAR sample it was
observed with a maximum 0.15 arcsec resolution, therefore
now resulting in a super-optimal linear resolution.
-D>8 = The new distance determined from the Vlsr of ALMAGAL dense
tracer lines, puts the source beyond the distance limit used
to select the original sample.
-refit40k = The dust temperature estimated from Herschel fluxes has been
updated here with respect to Elia et al.
(2017MNRAS.471..100E 2017MNRAS.471..100E, Cat. J/MNRAS/471/100,
2021MNRAS.504.2742E 2021MNRAS.504.2742E) due to a 40K hard limit that was
reached in the grey-body fit.
-sed_irr = RMS source with a Hi-GAL counterpart in the Herschel 5 bands,
but the SED is irregular (not a single downward-facing
concavity) and did not pass criteria to be included in Elia
et al. (2017MNRAS.471..100E 2017MNRAS.471..100E, Cat. J/MNRAS/471/100,
2021MNRAS.504.2742E 2021MNRAS.504.2742E). This criteria have been relaxed for
the present work to estimate physical parameters.
-sed_rebuilt = RMS source not in Elia et al. (2017MNRAS.471..100E 2017MNRAS.471..100E,
Cat. J/MNRAS/471/100, 2021MNRAS.504.2742E 2021MNRAS.504.2742E), that needed a
custom build of the Herschel SED to estimate physical
parameters in the present work. Possible reasons: source
had multiple counterparts in one Herschel band, or
counterparts were not linked in a single SED.
-sed_sat = RMS source not in Elia et al. (2017MNRAS.471..100E 2017MNRAS.471..100E,
Cat. J/MNRAS/471/100, 2021MNRAS.504.2742E 2021MNRAS.504.2742E) due to saturation
in some Herschel bands. To estimate physical parameters for
the present work the SED has been manually built allowing
missing bands.
-sed_noband = RMS source not in Elia et al. (2017MNRAS.471..100E 2017MNRAS.471..100E,
Cat. J/MNRAS/471/100, 2021MNRAS.504.2742E 2021MNRAS.504.2742E) because of
missing 350-500um Herschel bands due to source faintness.
Physical parameters for the present work are estimated
using three remaining bands.
-no_props = RMS source not in Elia et al. (2017MNRAS.471..100E 2017MNRAS.471..100E,
Cat. J/MNRAS/471/100, 2021MNRAS.504.2742E 2021MNRAS.504.2742E) because has a
Herschel counterpart in 1 or 2 bands only. It was not
possible to estimate physical parameters.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Num Target clump running number
6- 11 E6.1 pc2 Alin-5s ? Area of 5-sigma continuum RoI
13- 17 F5.2 % Afrac-5s ? Area of 5-sigma continuum RoI/FoV
19- 23 F5.3 --- Dcirc-5s ? Departure from circularity parameter
25- 29 F5.3 --- Qhull-5s ? Area RoI/Area Convex Hull
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Acknowledgements:
Sergio Molinari, sergio.molinari(at)inaf.it
References:
Sanchez-Monge et al., Paper II 2025A&A...696A.150S 2025A&A...696A.150S
Coletta et al., Paper III 2025A&A...696A.151C 2025A&A...696A.151C, Cat. J/A+A/696/A151
(End) Patricia Vannier [CDS] 15-Feb-2025