J/ApJ/824/95 Near-infrared imaging polarimetry of GGD 27 (Kwon+, 2016)
Near-infrared imaging polarimetry of GGD 27: circular polarization and
magnetic field structures.
Kwon J., Tamura M., Hough J.H., Nagata T., Kusakabe N., Saito H.
<Astrophys. J., 824, 95-95 (2016)>
=2016ApJ...824...95K 2016ApJ...824...95K (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Photometry, infrared ; Polarization
Keywords: circumstellar matter; infrared: stars; ISM: "GGD 27";
ISM: structure; polarization; stars: formation
Abstract:
Near-infrared imaging polarimetry in the J, H, and K_ s_ bands was
carried out for GGD 27 in the dark cloud Lynds 291. Details of an
infrared reflection nebula associated with the optical nebulosity
GGD27 and the infrared nebula GGD 27 IRS are presented. Aperture
photometry of 1263 point-like sources, detected in all three bands,
was used to classify them based on a color-color diagram, and the
linear polarization of several hundred sources was determined, with
the latter used to map the magnetic field structure around GGD 27.
This field, around GGD 27 IRS, appears to be associated with the
extended CO outflow of IRAS 18162-2048; however, there are partly
distorted or bent components in the field. The Chandrasekhar-Fermi
method gives an estimate of the magnetic field strength as ∼90µG. A
region associated with GGD 27 IRS is discovered to have a circular
polarization in the range of ∼2%-11% in the Ks band. The circular
polarization has an asymmetric positive/negative pattern and extends
out to ∼120" or 1.0pc. The circular and linear polarization patterns
are explained as resulting from a combination of dense inner and
fainter outer lobes, suggesting episodic outflow.
Description:
Observations in the direction of GGD 27 IRS were carried out using the
SIRPOL imaging polarimeter at the Infrared Survey Facility (IRSF) 1.4m
telescope at SAAO in South Africa. The Facility enables deep
wide-field (7.7'x7.7' at a scale of 0.453"/pixel) simultaneous imaging
polarimetry in the JHKs bands.
Linear polarimetry was performed on the night of 2006 March 14.
Circular polarimetry observations of the GGD 27 IRS regions were made
on the nights of 2008 July 24 and 2014 March 21.
Objects:
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RA (ICRS) DE Designation(s)
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18 19 12.08 -20 47 50.9 GGD 27 IRS = NAME GGD 27 IRS
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 69 1263 Photometry of point-like sources in
the GGD 27 IRS region
table2.dat 82 1263 Polarimetry of point-like sources in
the GGD 27 IRS region
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See also:
VII/7 : Lynds' Catalogue of Dark Nebulae (LDN) (Lynds 1962)
J/ApJS/220/17 : Wide-field NIR polarimetry of ρ Oph cloud (Kwon+, 2015)
J/ApJ/775/84 : Polarization from stars behind IC63 nebula (Andersson+, 2013)
J/ApJ/741/35 : NIR photometry and polarization in NGC 2264 (Kwon+, 2011)
J/ApJ/720/1045 : Polarimetry toward sightlines through ChaI (Andersson+, 2010)
J/ApJ/708/758 : Polarimetry of HH1-2 region (Kwon+, 2010)
J/A+A/504/853 : Molecular lines in 5 massive dense cores (Herpin, 2009)
J/ApJS/182/143 : SCUPOL Legacy polarimetry of SCUBA (Matthews+, 2009)
J/ApJ/685/1005 : Spitzer and high-mass star forming regions (Qiu+, 2008)
J/AJ/136/621 : Near-infrared polarimetry of M42 (Kusakabe+, 2008)
J/ApJ/665/369 : Photopolarimetry of Southern Coalsack stars (Andersson+, 2007)
J/ApJ/650/945 : Polarisation around filamentary cloud GF 9 (Poidevin+, 2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq Running sequence number (G1)
6- 7 I2 h RAh [18] Hour of Right Ascension (J2000) (2)
9- 10 I2 min RAm [18/19] Minute of Right Ascension (J2000) (2)
12- 16 F5.2 s RAs Second of Right Ascension (J2000) (2)
18 A1 --- DE- [-] Sign of the Declination (J2000)(2)
19- 20 I2 deg DEd [20] Degree of Declination (J2000) (2)
22- 23 I2 arcmin DEm Arcminute of Declination (J2000) (2)
25- 28 F4.1 arcsec DEs Arcsecond of Declination (J2000) (2)
30- 35 F6.3 mag Jmag [9.5/17.9] The J band magnitude (3)
37- 41 F5.3 mag e_Jmag [0/0.1] Uncertainty in Jmag
43- 48 F6.3 mag Hmag [9/16.1] The H band magnitude (3)
50- 54 F5.3 mag e_Hmag [0/0.08] Uncertainty in Hmag
56- 61 F6.3 mag Ksmag [8.8/15.8] The Ks band magnitude (3)
63- 67 F5.3 mag e_Ksmag [0/0.1] Uncertainty in Ksmag
69 A1 --- Group [A-C] Group identifier (4)
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Note (2): Positions are from the J-H-Ks image (see Figure 1).
Note (3): The color and magnitude of the photometry were transformed into the
2MASS system using Equation (2):
MAG2MASS=MAGIRSF+α1xCOLORIRSF+Β1 and Equation (3):
COLOR2MASS=α2xCOLORIRSF+Β2
where MAGIRSF is the instrumental magnitude from the IRSF images
and MAG2MASS is the magnitude from the 2MASS PSC.
See section 3.1 for further details.
Note (4): Classification based on the color-color diagram of Figure 2.
Sources in domain A are either field stars or YSOs with little
infrared excess and substantial reddening. Domain B is adjacent to
domain A in the direction of higher H-Ks (to the right) and above
the locus of classical T Tauri stars. Sources in domain B are
pre-main-sequence stars with infrared excess emission from
circumstellar material. Domain C, adjacent to and to the right of
domain B, contains infrared protostars and Class I sources.
See Section 4.1.1 for further explanations.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq Running sequence number (G1)
6- 11 F6.3 % PJ [0.15/29.6] Polarization in J band
13- 17 F5.2 % e_PJ [0.03/27.2] Uncertainty in PJ
19- 24 F6.3 % PH [0.05/42.8] Polarization in H band
26- 29 F4.2 % e_PH [0.02/6.3] Uncertainty in PH
31- 36 F6.3 % PKs [0.006/57] Polarization in Ks band
38- 42 F5.2 % e_PKs [0.03/12] Uncertainty in PKs
44- 49 F6.2 deg thetaJ [0.02/180] Position angle in J band
51- 55 F5.1 deg e_thetaJ [0.5/655] Uncertainty in θJ
57- 62 F6.2 deg thetaH [0.1/180] Position angle in H band
64- 69 F6.1 deg e_thetaH [0.3/1266] Uncertainty in θH
71- 76 F6.2 deg thetaKs [0.05/180] Position angle in Ks band
78- 82 F5.1 deg e_thetaKs [0.3/524] Uncertainty in θKs
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Global notes:
Note (G1): In this paper, sources with P/δP>3 are used.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 17-Aug-2016