J/A+A/626/A93 IRAS 16293-2422 spectral cubes (van der Wiel+, 2019)
The ALMA-PILS survey: gas dynamics in IRAS 16293-2422 and the connection
between its two protostars.
van der Wiel M.H.D., Jacobsen S.K., Jorgensen J.K., Bourke T.L.,
Kristensen L.E., Bjerkeli P., Murillo N.M., Calcutt H., Mueller H.S.P.,
Coutens A., Drozdovskaya M.N., Favre C., Wampfler S.F.
<Astron. Astrophys. 626, A93 (2019)>
=2019A&A...626A..93V 2019A&A...626A..93V (SIMBAD/NED BibCode)
ADC_Keywords: Infrared sources ; Radio lines
Keywords: ISM: individual objects: IRAS 16293-2422 - stars: formation -
circumstellar matter - ISM: jets and outflows
Abstract:
The majority of stars form in binary or higher order systems. The
Class 0 protostellar system IRAS16293-2422 contains two protostars,
'A' and 'B', separated by ∼600au and embedded in a single, 10^4 au
scale envelope. Their relative evolutionary stages have been debated.
We aim to study the relation and interplay between the two protostars
A and B at spatial scales of 60 to ∼1000au.
We selected molecular gas line transitions of CO, H2CO, HCN, CS,
SiO, and CCH from the ALMA-PILS spectral imaging survey (329-363GHz)
and used them as tracers of kinematics, density, and temperature in
the IRAS16293-2422 system. The angular resolution of the PILS data set
allows us to study these quantities at a resolution of 0.5 arcsec (60
au at the distance of the source).
Line-of-sight velocity maps of both optically thick and optically thin
molecular lines reveal: (i) new manifestations of previously known
outflows emanating from protostar A; (ii) a kinematically quiescent
bridge of dust and gas spanning between the two protostars, with an
inferred density between 4x104 and 3x107cm-3; and (iii) a
separate, straight filament seemingly connected to protostar B seen
only in CCH, with a flat kinematic signature. Signs of various
outflows, all emanating from source A, are evidence of high-density
and warmer gas; none of them coincide spatially and kinematically with
the bridge.
We hypothesize that the bridge arc is a remnant of filamentary
substructure in the protostellar envelope material from which
protostellar sources A and B have formed. One particular morphological
structure appears to be due to outflowing gas impacting the quiescent
bridge material. The continuing lack of clear outflow signatures
unambiguously associated to protostar B and the vertically extended
shape derived for its disk-like structure lead us to conclude that
source B may be in an earlier evolutionary stage than source A.
Description:
This data collection contains nine spectral cubes (RA, DE, frequency)
extracted from the ALMA-PILS dataset. The observation setup and
details concerning the processing performed are given in Jorgensen et
al. (2016A&A...595A.117J 2016A&A...595A.117J) and van der Wiel et al.
(2019A&A...626A..93V 2019A&A...626A..93V). In short, interferometric baselines of the ∼47
element array range up to 300m. Phase-only self-calibration was
performed based on the continuum signal, first separately for the
Atacama Compact Array (ACA) and the main ALMA array. The final imaging
of the combined dataset used Briggs waiting with robust=0.5 and a
restoring beam fwhm of 0.5-arcsec was imposed. The resulting spectral
cubes samples angular scales between 0.5-arcsec and 13-arcsec.
Spectral channels are uniform in frequency space, each being 0.244MHz
wide. The FITS cubes delivered here cover a frequency range defined by
±20km/s centered around the rest frequency of the following
molecular transitions (see also Table 2 in the paper):
* 337.06100GHz (C17O 3-2);
* 345.79600GHz (CO 3-2);
* 345.33977GHz (H13CN 4-3);
* 351.76864GHz (o-H2CO 5(1,5)-4(1,4));
* 343.32571GHz (o-H2(13C)O 5(1,5)-4(1,4));
* 337.39646GHz (C34S 7-6);
* 347.33058GHz (SiO 8-7);
* 342.98084GHz (29SiO 8-7);
* 349.39997GHz (C2H 4(7/2)-3(5/2)).
Broadband continuum signal has been substracted following the strategy
outlined in Sect. 3.1.2 of Jorgensen et al. (2016A&A...595A.117J 2016A&A...595A.117J),
which is needed to cope with the extremely high density of line signal
in the spectral domain.
Objects:
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RA (2000) DE Designation(s)
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16 32 22.56 -24 28 31.8 IRAS 16293-2422 = WISE J163222.62-242833.6
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 143 9 List of datacubes
fits/* . 9 Individual datacubes
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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- 22 I3 --- Nx Number of pixels along X-axis
24- 26 I3 --- Ny Number of pixels along Y-axis
28- 30 I3 --- Nz Number of slices
32- 57 A26 "datime" Obs.date Observation date
59- 65 F7.3 GHz bFreq Lower value of observed frequency
67- 73 F7.3 GHz BFreq Upper value of observed frequency
75- 80 I6 Hz dFreq Frequency resolution
82- 86 I5 Kibyte size Size of FITS file
88- 97 A10 --- FileName Name of FITS file, in subdirectory fits
99-143 A45 --- Title Title of the FITS file
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Acknowledgements:
Matthijs van der Wiel, mhd(at)vanderwiel.org
(End) Patricia Vannier [CDS] 29-May-2019