J/A+A/636/A38 W43-MM1 ALMA 12CO(2-1) datacube (Nony+, 2020)
Episodic accretion constrained by a rich cluster of outflows.
Nony T., Motte F., Louvet F., Plunkett A., Gusdorf A., Fechtenbaum S.,
Pouteau Y., Lefloch B., Bontemps S., Molet J., Robitaille J.-F.
<Astron. Astrophys. 636, A38 (2020)>
=2020A&A...636A..38N 2020A&A...636A..38N (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Radio lines
Keywords: stars: formation - stars: protostars - ISM: jets and outflows
Abstract:
The accretion history of protostars remains widely mysterious even
though it represents one of the best ways to understand the
protostellar collapse that leads to the formation of stars.
Molecular outflows, which are easier to detect than the direct
accretion onto the prostellar embryo, are here used to characterize
the protostellar accretion phase in W43-MM1.
The W43-MM1 protocluster hosts a sufficient number of protostars to
statistically investigate molecular outflows in a single, homogeneous
region. We used the CO(2-1) and SiO(5-4) line datacubes, taken as part
of an ALMA mosaic with a 2000 AU resolution, to search for
protostellar outflows, evaluate the influence that the environment has
on these outflows' characteristics and put constraints on outflow
variability in W43-MM1.
We discovered a rich cluster of 46 outflow lobes, driven by 27
protostars with masses of 1-100M☉. The complex environment
inside which these outflow lobes develop has a definite influence on
their length, limiting the validity of using outflow's dynamical
timescales as a proxy of the ejection timescale in clouds with high
dynamics and varying conditions. We performed a detailed study of
Position-Velocity (PV) diagrams of outflows that revealed clear events
of episodic ejection. The time variability of W43-MM1 outflows is a
general trend and is more generally observed than in nearby, low- to
intermediate-mass star-forming regions. The typical timescale found
between two ejecta, ∼500yr, is consistent with that found in nearby
protostars.
If ejection episodicity reflects variability in the accretion process,
either protostellar accretion is more variable or episodicity is
easier to detect in high-mass star-forming regions than in nearby
clouds. The timescale found between accretion events could be
resulting from instabilities, associated with bursts of inflowing gas
arising from the close dynamical environment of highmass star-forming
cores.
Description:
We present 12CO(2-1) line observations of the protocluster W43-MM1.
Observations were carried out with ALMA in the 12m and 7m arrays taken
between July 2014 and June 2015.
Objects:
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RA (2000) DE Designation(s)
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18 47 47.0 -01 54 28 W43-MM1 = [MSL2003] W43-MM1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 163 1 Information of fits datacube
fits/* . 1 Datacube
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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- 32 I3 --- Nz Number of pixels along Z-axis
34- 59 A26 "datime" Obs.date Observation date
61- 67 F7.3 GHz bFreq Lower value of frequency interval
69- 75 F7.3 GHz BFreq Upper value of frequency interval
77- 82 I6 Hz dFreq Frequency resolution
84- 90 I7 Kibyte size Size of FITS file
92-119 A28 --- FileName Name of FITS file, in subdirectory fits
121-163 A43 --- Title Title of the FITS file
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Acknowledgements:
Thomas Nony, thomas.nony(at)univ-grenoble-alpes.fr
(End) Patricia Vannier [CDS] 26-Feb-2020