J/ApJ/847/92 Polarization data toward the protostar Serpens SMM1 (Hull+, 2017)
ALMA observations of dust polarization and molecular line emission from the
class 0 protostellar source Serpens SMM1.
Hull C.L.H., Girart J.M., Tychoniec L., Rao R., Cortes P.C., Pokhrel R.,
Zhang Q., Houde M., Dunham M.M., Kristensen L.E., Lai S.-P., Li Z.-Y.,
Plambeck R.L.
<Astrophys. J., 847, 92 (2017)>
=2017ApJ...847...92H 2017ApJ...847...92H
ADC_Keywords: Polarization; Millimetric/submm sources; Interstellar medium;
YSOs
Keywords: ISM: jets and outflows ; ISM: magnetic fields ; polarization ;
stars: formation ; stars: magnetic field ; stars: protostars
Abstract:
We present high angular resolution dust polarization and molecular
line observations carried out with the Atacama Large
Millimeter/submillimeter Array (ALMA) toward the Class 0 protostar
Serpens SMM1. By complementing these observations with new
polarization observations from the Submillimeter Array (SMA) and
archival data from the Combined Array for Research in Millimeter- wave
Astronomy (CARMA) and the James Clerk Maxwell Telescopes (JCMT), we
can compare the magnetic field orientations at different spatial
scales. We find major changes in the magnetic field orientation
between large (∼0.1pc) scales-where the magnetic field is oriented
E-W, perpendicular to the major axis of the dusty filament where SMM1
is embedded-and the intermediate and small scales probed by CARMA
(∼1000au resolution), the SMA (∼350au resolution), and ALMA (∼140au
resolution). The ALMA maps reveal that the redshifted lobe of the
bipolar outflow is shaping the magnetic field in SMM1 on the southeast
side of the source; however, on the northwestern side and elsewhere in
the source, low-velocity shocks may be causing the observed chaotic
magnetic field pattern. High-spatial-resolution continuum and
spectral-line observations also reveal a tight (∼130au) protobinary
system in SMM1-b, the eastern component of which is launching an
extremely high-velocity, one-sided jet visible in both CO(J=2->1) and
SiO(J=5->4); however, that jet does not appear to be shaping the
magnetic field. These observations show that with the sensitivity and
resolution of ALMA, we can now begin to understand the role that
feedback (e.g., from protostellar outflows) plays in shaping the
magnetic field in very young, star-forming sources like SMM1.
Description:
We present ALMA 343GHz (Band 7; 870um) polarization observations
toward the very embedded intermediate-mass protostar Serpens SMM1. We
complement these observations with new Submillimeter Array (SMA)
345GHz (880um) dust polarization observations as well as with archival
polarization maps obtained with the James Clerk Maxwell Telescope
(JCMT; 850um) and the Combined Array for Research in Millimeter-wave
Astronomy (CARMA; 1.3mm).
The 870um ALMA dust polarization observations that we present were
taken on 2015 June 3 and 7, and have a synthesized beam (resolution
element) of ∼0.33", corresponding to a linear resolution of ∼140au at
a distance of 436pc.
We also present 1.3mm (Band 6) ALMA spectral-line data, which were
taken in two different array configurations on 2014 August 18 (∼0.3"
angular resolution) and 2015 April 06 (∼1" resolution).
Finally, we present 1.3mm ALMA continuum data with ∼0.1" resolution
(R. Pokhrel et al. 2017, in preparation), observed on 2016 September
10, 13, and 2016 October 31.
The SMA polarization observations (Figure 1(c)) were taken on 2012 May
25 (compact configuration) and 2012 September 2 and 3 (extended
configuration), and have a synthesized beam of ∼0.8".
The archival JCMT SCUBA polarization data (Figure 1(a)) were obtained
from supplementary data provided by Matthews+ (2009, J/ApJS/182/143).
The CARMA polarization data (Figure 1(b)) were taken between 2011 and
2013 as part of the TADPOL survey (Hull+ 2014, J/ApJS/213/13). The
data were taken using the 1.3mm polarization receiver system in the C,
D, and E arrays at CARMA, which correspond to angular resolutions at
1.3mm of approximately 1", 2", and 4", respectively.
Objects:
---------------------------------------------------------------
RA (ICRS) DE Designation(s)
---------------------------------------------------------------
18 29 49.63 +01 15 21.9 Serpens SMM1 = NAME Serpens SMM 1
---------------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 36 4 SMM1 source properties
table3.dat 42 383 ALMA polarization data
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See also:
J/ApJ/707/103 : Observation of Ser FIRS 1 at 230GHz (Enoch+, 2009)
J/A+A/563/L3 : NGC1333-IRAS2A CALYPSO IRAM-PdBI SiO & SO maps (Codella+, 2014)
J/ApJ/783/6 : Deconvolved Spitzer images of 89 protostars (Velusamy+, 2014)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Name Source name
8- 9 I2 h RAh [18] Hour of right ascension (J2000)
11- 12 I2 min RAm [29] Minute of right ascension (J2000)
14- 18 F5.2 s RAs [49.6/50] Second of right ascension (J2000)
20 A1 --- DE- [+] Sign of declination (J2000)
21- 21 I1 deg DEd [1] Degree of declination (J2000)
23- 24 I2 arcmin DEm [15] Arcminute of declination (J2000)
26- 30 F5.2 arcsec DEs [20.4/23] Arcsecond of declination (J2000)
32- 36 F5.1 mJy/beam I870 [10/800] Peak intensity of each of the
sources in the 870um ALMA data
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg [277.456/277.459] Right Ascension (J2000)
11- 17 F7.5 deg DEdeg [1.254/1.258] Declination (J2000)
19- 23 F5.1 deg chi Polarization position angle
25- 27 F3.1 deg e_chi [0.2/9.5] Uncertainty in chi
29- 34 F6.3 mJy/beam Pol [0.18/10.86] Polarized intensity
36- 42 F7.3 mJy/beam Int [1.5/745]? Total intensity (1)
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Note (1): Reported where I>3σ. Due to differences in dynamic range
between the images of Stokes I and polarized intensity, there are
cases where Pol is detectable but I is not.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 31-May-2018