J/A+A/568/L5 HH 212 CO, CS and 850um ALMA images (Codella+, 2014)
The ALMA view of the protostellar system HH212.
The wind, the cavity, and the disk.
Codella C., Cabrit S., Gueth F., Podio L., Leurini S., Bachiller R.,
Gusdorf A., Lefloch B., Nisini B., Tafalla M., Yvart W.
<Astron. Astrophys. 568, L5 (2014)>
=2014A&A...568L...5C 2014A&A...568L...5C
ADC_Keywords: YSOs ; Interferometry ; Interstellar medium
Keywords: stars: formation - ISM: jets and outflows - ISM: molecules -
ISM: individual objects: HH212
Abstract:
We wish to exploit the unmatched combination of high angular
resolution, high sensitivity, high-imaging fidelity, and spectral
coverage provided by ALMA to shed light on the complex kinematics of
the innermost central regions of HH212 protostellar system.
We mapped the inner 10" (4500AU) of the HH212 system at ∼0.5"
resolution in several molecular tracers and in the 850um dust
continuum using the ALMA interferometer in band 7 in the extended
configuration of the Early Science Cycle 0 operations.
Within a single ALMA spectral set-up, we simultaneously identify all
the crucial ingredients known to be involved in the star formation
recipe: (i) the fast, collimated bipolar SiO jet driven by the
protostar; (ii) the large-scale swept-up CO outflow; (iii) the
flattened rotating and infalling envelope, with bipolar cavities
carved by the outflow (in C17O(3-2)); and (iv) a rotating wide-angle
flow that fills the cavities and surrounds the axial jet (in
C34S(7-6)). In addition, the compact high-velocity C17O emission
(±1.9-3.5km/s from systemic) shows a velocity gradient along the
equatorial plane consistent with a rotating disk of ∼0.2"=90AU around
a ∼0.3±0.1M☉ source. The rotating disk is possibly Keplerian.
HH212 is the third Class 0 protostar with possible signatures of a
Keplerian disk of radius ≥30AU. The warped geometry in our CS data
suggests that this large Keplerian disk might result from misaligned
magnetic and rotation axes during the collapse phase. The wide-angle
CS flow suggests that disk winds may be present in this source.
Description:
HH212 was observed with ALMA using 24 12m antennas on 2012 December 1
during the Early Science Cycle 0 phase. The shortest and longest
baselines were about 20m and 360m, from which we obtained a maximum
unfiltred scale of 3" at 850um. The C17O(3-2), SiO(8-7), and
C34S(7-6) lines at 337061.13MHz, 347330.63MHz, and 337396.69MHz,
respectively, were observed using spectral units of 488kHz (0.43km/s)
resolution.
Images have a typical clean-beam FWHM of (PA=35°), and an rms
noise of ∼1mJy/beam for continuum, and 3-4mJy/beam in the 0.44km/s
channels. Positions are given with respect to the MM1 protostar,
located at RAJ2000=05:43:51.41, DEJ2000=-01:02:53.17, in excellent
agreement with the coordinates derived by Lee et al.
(2014ApJ...786..114L 2014ApJ...786..114L) using ALMA.
Objects:
-----------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------
05 43 51.4 -01 02 53 HH 212 = HH 212
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 124 3 List of final reduced ALMA cube FITS files
fits/* . 3 Individual FITS files
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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 F4.2 arcsec/pix Scale [0.12]? Scale of the image
25- 27 I3 --- Nx [360] Number of pixels along X-axis
28 A1 --- --- [x]
29- 31 I3 --- Ny [360] Number of pixels along Y-axis
33- 35 I3 Kibyte size [262] Size of FITS file
37- 56 A20 --- FileName Name of the FITS file in subdirectory fits
58-124 A67 --- Title Title of the file
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Acknowledgements:
Claudio Codella, codella(at)arcetri.astro.it
(End) Patricia Vannier [CDS] 23-Jul-2014