J/A+A/629/A136 MWC 922 ALMA maps and datacubes (Sanchez Contreras+, 2019)
A rotating fast bipolar wind and disk system around the B[e]-type star MWC 922.
Sanchez Contreras C., Baez-Rubio A., Alcolea J., Castro-Carrizo A.,
Bujarrabal V., Martin-Pintado J., Tafoya D.
<Astron. Astrophys. 629, A136 (2019)>
=2019A&A...629A.136S 2019A&A...629A.136S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, Be ; Interferometry
Keywords: stars: emission-line, Be - circumstellar matter -
stars: winds, outflows - stars: individual: MWC 922 - HII regions -
radio lines: stars
Abstract:
We present interferometric observations with the Atacama Large
Millimeter Array (ALMA) of the free-free continuum and recombination
line emission at 1 and 3mm of the Red Square Nebula surrounding the
B[e]-type star MWC922. The distance to the source, which is unknown,
is usually taken to be d=1.7-3kpc. The unprecedented angular
resolution (up to ∼0.02") and exquisite sensitivity of these data
reveal for the first time the structure and kinematics of the nascent
compact ionized region at its center. We imaged the line emission of
H30α and H39α, previously detected with single-dish
observations, and of H51ε, H55γ, and H63δ,
detected for the first time in this work. The line emission is seen
over a full velocity range of ∼180km/s arising in a region of diameter
<0.14" (less than a few hundred au) in the maser line H30α,
which is the most intense transition reported here. We resolve the
spatio-kinematic structure of a nearly edge-on disk rotating around a
central mass of ∼10M☉ (d=1.7kpc) or ∼18M☉ (d=3kpc),
assuming Keplerian rotation. Our data also reveal a fast (∼100km/s)
bipolar ejection (possibly a jet) orthogonal to the disk. In addition,
a slow (<15km/s) wind may be emanating from the disk. Both, the slow
and the fast winds are found to be rotating in a similar manner to the
ionized layers of the disk. This represents the first empirical proof
of rotation in a bipolar wind expanding at high velocity (∼100km/s).
Description:
Continuum (2D) and spectral line (3D) images of MWC922 at millimeter
wavelengths observed with the ALMA interferometer. A selection of line
cubes (H30α and H39α) is provided. Observational details
are given in the text (sect. 2) and in the captions of figures 1, A.3
and A.4.
Objects:
-----------------------------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------------------------
18 21 16.06 -13 01 25.7 MWC922 = AME Red Square Nebula
-----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 111 4 List of fits files
fits/* . 4 Individual fits files
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
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 slices for the datacubes
34- 41 F8.1 m/s VRAD VRAD value for the maps or
lower value of VRAD interval for the datacubes
43- 48 I6 m/s BVRAD ? Upper value of VRAD interval for the datacubes
50- 53 I4 m/s dVRAD ? VRAD resolution for the datacubes
55- 61 I7 Kibyte size Size of FITS file
63- 93 A31 --- FileName Name of FITS file, in subdirectory fits
95-111 A17 --- Title Title of the FITS file
--------------------------------------------------------------------------------
Acknowledgements:
Carmen Sanchez Contreras, csanchez(at)cab.inta-csic.es
(End) Patricia Vannier [CDS] 09-Aug-2019