J/ApJ/838/80 JHK polarimetry of stars behind bubble N4 (Chen+, 2017)
A curved magnetic field in the ring-like shell of bubble N4.
Chen Z., Jiang Z., Tamura M., Kwon J., Roman-Lopes A.
<Astrophys. J., 838, 80-80 (2017)>
=2017ApJ...838...80C 2017ApJ...838...80C (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium ; Polarization ; Infrared sources
Keywords: ISM: bubbles; ISM: individual objects: N4;
ISM: magnetic fields; polarization
Abstract:
We report the detection of a curved magnetic field in the ring-like
shell of the bubble N4, derived from near-infrared polarization of
reddened diskless stars located behind this bubble. The magnetic field
in the shell is curved and parallel to the ring-like shell, and its
strength is estimated to be ∼120µG in the plane of the sky. The
magnetic field strength in the shell is significantly enhanced
compared to the local field strength. We calculate the mass-to-flux
ratio for the submillimeter clumps in the shell and find that they are
all magnetically subcritical. Our results demonstrate that the
magnetic field strengthens as the interstellar medium is compressed
into a shell, and suggest that the magnetic field has the potential to
hinder star formation triggered by H II region expansion.
Description:
The current paper makes use of data taken using SIRPOL, mounted on the
Infrared Survey Facility 1.4m telescope at the South African
Astronomical Observatory, during the nights of 2013 July 7-9. The
instrument performance, observational information, weather conditions,
and data reduction process were previously described in Paper I
(Chen+, 2016ApJ...822..114C 2016ApJ...822..114C).
The average full width at half maximum (FWHM) of point sources in the
J-, H-, and Ks-bands is 2.0", 1.9", and 1.8", respectively.
Objects:
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RA (ICRS) DE Designation(s)
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18 08 52.6 -18 16 07 N4 = [CPA2006] N4
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 84 356 JHK-band polarimetric data of the background
stars behind bubble N4
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See also:
VIII/58 : A Survey of Radio H II Regions in the Northern Sky (Lockman+ 1989)
J/ApJ/649/759 : Bubbles in the galactic disk (Churchwell+, 2006)
J/A+A/544/A146 : ATLASGAL cold high-mass clumps with NH3 (Wienen+, 2012)
J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013)
J/A+A/565/A75 : ATLASGAL. Dust condensations in Gal. plane (Csengeri+, 2014)
J/ApJ/818/95 : YSO candidates within 5' from the IR bubble N4 (Liu+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
12- 21 F10.6 deg DEdeg Declination in decimal degrees (J2000)
23- 26 F4.1 % Pol(H) [0.4/10.3] Polarization degree at H-band
28- 30 F3.1 % e_Pol(H) [0/1] Error of polarization degree at H-band
32- 34 I3 deg PA(H) [0/180] Position angle at H-band
36 I1 deg e_PA(H) [0/9] Error of position angle at H-band
38- 42 F5.1 % Pol(J) [0.6/12]?=-99 Polarization degree at J-band
44- 48 F5.1 % e_Pol(J) [0.2/0.9]?=-99 Pol(J) uncertainty
50- 54 F5.1 deg PA(J) [0.7/177]?=-99 Position angle at J-band
56- 60 F5.1 deg e_PA(J) [0.5/9]?=-99 PA(J) uncertainty
62- 66 F5.1 % Pol(K) [0.3/11.4]?=-99 Polarization degree at K-band
68- 72 F5.1 % e_Pol(K) [0/0.9]?=-99 Pol(K) uncertainty
74- 78 F5.1 deg PA(K) [0.9/179]?=-99 Position angle at K-band
80- 84 F5.1 deg e_PA(K) [0.1/9.4]?=-99 PA(K) uncertainty
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Acknowledgements:
Additional polarimetric data at J and Ks bands were provided by the author:
zwchen {at} pmo.ac.cn [Purple Mountain Observatory, China]
Note that some sources don't have measurable J or Ks band polarization.
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 30-Oct-2017