J/A+A/708/A251 Catalog of astrodendro leaves (Xu+, 2026)
Linear filament and nested cluster evolution tomography (LANCET).
I. Capture the evolution of dense gas in 14-parsec filament G316.8.
Xu F., Wang K., Schneider N., Galvan-Madrid R., van der Tak F.F.S.,
Ginsburg A., Tan J.C., Liu H.B., Zhang Q., Jiao W., Garay G., Jiao S.,
Su K., Jones B.M., Zhu L.
<Astron. Astrophys. 708, A251 (2026)>
=2026A&A...708A.251X 2026A&A...708A.251X (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium ; Infrared
Keywords: stars: formation - stars: massive - ISM: cloud - ISM: structure
Abstract:
A dynamic view of mass assembly is essential for understanding the
formation of massive stars and clusters. However, interpreting
evolutionary diagnostics from Galactic-wide surveys requires careful
consideration of distance and environmental variations. The G316.8
filament provides an excellent controlled case: a 14-parsec, nearly
linear structure comprising three contiguous subregions with
comparable molecular gas reservoirs (each ∼10000M☉), yet
spanning a clear evolutionary sequence from a northern infrared dark
cloud (young) through a central massive young stellar object
(intermediate), to a southern HII region (evolved). The Linear
filament and nested cluster evolution tomography (LANCET) project
mapped the entire G316.8 filament with the Atacama Compact Array (ACA)
at 1.3mm, achieving 6 arcsec (0.08pc) resolution over 26.7 arcmin2
(17.1pc2). By combining ACA 7m data with Herschel and APEX/ArT'eMiS
observations, we produced high-resolution temperature and
column-density maps. We quantified subregional differences using (i)
dense-fragment statistics, (ii) column-density probability
distribution functions (N-PDFs), and (iii) the scale-dependent
structural diagnostic, the delta-variance. From young to intermediate
to evolved, the maximum fragment mass increases from 8 to 160 to
490M☉, while the dense-gas mass fraction (>0.5g/cm2) rises
from 0.4% to 2.3% to 9.6%. Along this sequence, the N-PDF develops a
slightly flatter primary power-law tail and an additional, steeper
secondary tail; the delta-variance slope becomes progressively
shallower. Across G316.8, the subregional differences consistently
indicate a coherent evolutionary trend of massive star formation, in
which gas is continuously assembled into sub-parsec dense structures.
The forthcoming 12m array observations are about to extend this
dynamic picture by resolving dense core formation and probing gas
kinematics and magnetic fields.
Description:
We presented a 118-pointing mosaic of the 14-parsec-long linear
filament G316.8, which exhibits a clear in situ evolutionary
sequence from the northern (young), central (intermediate), and
southern (evolved) subregions. In this first paper of the series, we
processed and analyzed the Atacama Compact Array (ACA) 7m continuum
data and combined them with Herschel and APEX data as zero spacings.
We produced multi-resolution temperature and column-density images
with effective angular resolutions of 18" (global) and 6" (over the
highest-density footprint), corresponding to ∼0.24 pc and ∼0.08pc
at 2.8kpc.
A total of 65 leaves were identified and extracted. They are listed in
descending order of flux density in Table 2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 93 65 Catalog of astrodendro leaves
list.dat 132 5 List of fits maps
fits/* . 5 Individual fits maps
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- ID Sequential number
4- 5 I2 h RAh Right Accession (ICRS)
7- 8 I2 min RAm Right Accession (ICRS)
10- 14 F5.2 s RAs Right Accession (ICRS)
16 A1 --- DE- Declination sign (ICRS)
17- 18 I2 deg DEd Declination (ICRS)
20- 21 I2 arcmin DEm Declination (ICRS)
23- 26 F4.1 arcsec DEs Declination (ICRS)
28- 32 F5.3 Jy Flux Flux density at 1.3mm
34- 37 F4.1 arcsec thetamaj Measured major FWHM
39- 42 F4.1 arcsec thetamin Measured minor FWHM
44- 47 I4 deg PA [] Position angle
49- 52 F4.1 arcsec Rtheta Geometric mean FWHM in angular scale
54- 57 F4.2 pc Rp ?=- Geometric mean in physical scale
59- 62 F4.1 arcsec Rthetadec ?=- Deconvolved geometric mean FWHM
in angular scale
64- 67 F4.2 pc Rpdec ?=- Deconvolved geometric mean FWHM
in physical scale
69- 72 F4.1 K Tleaf Mean dust temperature of the leaf
74- 76 I3 Msun Massleaf Dendrogram leaf mass calculated from
monochromatic flux
78- 80 I3 Msun Massenc Dendrogram leaf calculated from enclosed
pixels
82- 93 A12 --- Subregion Region flag (young, intermediate or evolved)
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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- 23 I4 --- Nx Number of pixels along X-axis
25- 28 I4 --- Ny Number of pixels along Y-axis
30- 52 A23 "datime" Obs.date Observation date
54- 58 I5 Kibyte size Size of FITS file
60- 93 A34 --- FileName Name of FITS file, in subdirectory fits
95-132 A38 --- Title Title of the FITS file
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Acknowledgements:
Fengwei Xu, fengwei(at)mpia.de
License: CC-BY-4.0 [see https://spdx.org/licenses/]
(End) Patricia Vannier [CDS] 20-Mar-2026