J/ApJ/741/35 NIR photometry and polarization in NGC 2264 (Kwon+, 2011)
Complex scattered radiation fields and multiple magnetic fields in the
protostellar cluster in NGC 2264.
Kwon J., Tamura M., Kandori R., Kusakabe N., Hashimoto J., Nakajima Y.,
Nakamura F., Nagayama T., Nagata T., Hough J.H., Werner M.W., Teixeira P.S.
<Astrophys. J., 741, 35 (2011)>
=2011ApJ...741...35K 2011ApJ...741...35K
ADC_Keywords: Molecular clouds ; Photometry, infrared ; Polarization ;
Stars, pre-main sequence ; Interstellar medium
Keywords: circumstellar matter - infrared: stars - stars: formation -
ISM: individual objects (NGC 2264) - ISM: structure - polarization
Abstract:
Near-infrared imaging polarimetry in the J, H, and Ks bands has been
carried out for the protostellar cluster region around NGC 2264 IRS 2
in the Monoceros OB1 molecular cloud. Various infrared reflection
nebula clusters (IRNCs) associated with NGC 2264 IRS 2 and the IRAS 12
S1 core, as well as local infrared reflection nebulae (IRNe), were
detected. The illuminating sources of the IRNe were identified with
known or new near- and mid-infrared sources. In addition, 314
point-like sources were detected in all three bands and their aperture
polarimetry was studied. Using a color-color diagram, reddened field
stars and diskless pre-main-sequence stars were selected to trace the
magnetic field (MF) structure of the molecular cloud. The mean
polarization position angle of the point-like sources is 81±29°
in the cluster core, and 58±24° in the perimeter of the cluster
core, which is interpreted as the projected direction on the sky of
the MF in the observed region of the cloud. The Chandrasekhar-Fermi
method gives a rough estimate of the MF strength to be about 100uG.
A comparison with recent numerical simulations of the cluster
formation implies that the cloud dynamics is controlled by the
relatively strong MF. The local MF direction is well associated with
that of CO outflow for IRAS 12 S1 and consistent with that inferred
from submillimeter polarimetry. In contrast, the local MF direction
runs roughly perpendicular to the Galactic MF direction.
Description:
The observations in the direction of the IRAS 12 S1 region were
carried out, on the night of 2007 February 19, using the SIRPOL
imaging polarimeter on the Infrared Survey Facility (IRSF) 1.4m
telescope at the South African Astronomical Observatory. SIRPOL
consists of a single-beam polarimeter and an imaging camera.
Mid-IR data obtained from Spitzer IRAC (InfraRed Array Camera) and
MIPS (Multiband Imaging Photometer for Spitzer) were used for data
analysis as well as our near-IR data. The IRAC 5.8um data were
acquired in two epochs seven months apart (2004 March 6 and October
8). The MIPS 24um data were obtained on 2004 March 16.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 415 314 Photometry of point-like sources in the
Spokes Cluster
table2.dat 76 314 Polarimetry of point-like sources in the
Spokes Cluster
names.dat 53 1475 All names (from table1.dat)
refs.dat 153 50 References
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/AJ/138/963 : Rotation of NGC 2264 members (Baxter+, 2009)
J/AJ/138/1116 : A Spitzer view of NGC 2264 (Sung+, 2009)
J/AJ/135/441 : VRIHα photometry in NGC 2264 (Sung+, 2008)
J/AJ/134/999 : X-ray observations of NGC 2264 (Dahm+, 2007)
J/MNRAS/375/1220 : BVI photometry of young stars in 10 clusters (Mayne+, 2007)
J/ApJ/671/605 : NGC 2264 and ONC PMS stars in the infrared (Cieza+, 2007)
J/ApJ/642/972 : Star-forming core IR photometry in NGC 2264 (Young+, 2006)
J/A+A/455/903 : ACIS-I observations of NGC 2264 (Flaccomio+, 2006)
J/ApJ/648/1090 : Radial velocities of NGC 2264 stars (Furesz+, 2006)
J/A+A/430/1005 : VRIHα photometry of NGC 2264 variables (Lamm+, 2005)
J/AJ/129/829 : Hα emission stars in NGC 2264 (Dahm+, 2005)
J/A+A/417/557 : Rotation + variability of PMS Stars in NGC 2264 (Lamm, 2004)
J/AJ/127/1117 : Halpha emission-line stars in NGC2264 (Reipurth+, 2004)
J/AJ/127/2228 : VRI photometry of PMS stars in NGC 2264 OB (Makidon+, 2004)
J/AJ/128/1684 : NGC 2264: VRIHα photometry (Sung+, 2004)
J/AJ/123/1528 : UBV(RI)C and JHK photometry in NGC 2264 (Rebull+, 2002)
J/A+A/355/651 : HRI observations of PMS stars in NGC 2264 (Flaccomio+, 2000)
J/A+A/345/521 : BVRI photometry of NGC 2264 (Flaccomio+, 1999)
J/AJ/114/2644 : UBVRIHa photometry of NGC2264 (Sung+, 1997)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/314] Running sequence number
5 I1 h RAh [6] Hour of right ascension (J2000) (1)
7- 8 I2 min RAm [40/41] Minute of right ascension (J2000)
10- 14 F5.2 s RAs Second of right ascension (J2000)
16 A1 --- DE- [+] Sign of declination (J2000) (1)
17 I1 deg DEd [9] Degree of declination (J2000) (1)
19- 20 I2 arcmin DEm [30/38] Arcminute of declination (J2000)
22- 25 F4.1 arcsec DEs Arcsecond of declination (J2000)
27- 43 A17 --- 2MASS 2MASS name if any (JHHMMSSss+DDMMSSs)
45- 50 F6.3 mag Jmag J-band magnitude in 2MASS system (2)
52- 57 F6.3 mag Hmag H-band magnitude in 2MASS system (2)
59- 64 F6.3 mag Ksmag Ks-band magnitude in 2MASS system (2)
65 A1 --- n_Ksmag [n] Note for 2MASS J06405930+0935523 (3)
67- 68 A2 --- Group Group (A0, Ar, B or C) (4)
70-415 A346 --- Note Other identification(s) and object
type in parenthesis (see also refs.dat file)
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Note (1): Positions are from the J-H-Ks image (Figure 1).
Note (2): Photometric uncertainties are less than 0.1mag in all three bands.
Note (3): Note that since source 218 (AR 6A+6C) was saturated in the Ks
band, the Ks magnitude of 7.771mag obtained from 2MASS point-source
catalog was only used for the source classification (Figure 13). Also
note that the aperture photometry of source 314 (AR 6B) is considered
to be affected by the closest source 218 (AR 6A+6C).
Note (4): Classification based on a color-color diagram (see Section 4.2.1).
Groups summarize as follows:
A0 = Area near the locus of main-sequence/giant stars. Sources in domain A0
are either field stars (dwarfs and giants) or pre-main-sequence (PMS)
stars with little IR excess (weak-lined T Tauri stars and some classical
T Tauri stars) and with little reddening.
Ar = Sources in domain Ar are either field stars or PMS stars with little
IR excess and with substantial reddening.
B = Sources in domain B are PMS stars with IR excess emission from disks.
C = Sources in domain C are IR protostars or Class I sources.
Herbig AeBe stars tend to occupy lower parts of domains B and C.
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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- 3 I3 --- Seq [1/314] Running sequence number
5 A1 --- l_PJ Limit flag on PJ (5)
6- 11 F6.3 % PJ [0.16/50.9] J-band polarization
13- 18 F6.3 % e_PJ [0.013/10.4]? PJ 1σ error
20 A1 --- l_PH Limit flag on PH (5)
21- 26 F6.3 % PH H-band polarization
28- 32 F5.3 % e_PH ? PH 1σ error
34 A1 --- l_PKs Limit flag on PKs (5)
35- 40 F6.3 % PKs ? Ks-band polarization
42- 46 F5.3 % e_PKs ? PKs 1σ error
48- 52 F5.1 deg PAJ [9.3/179.1]? J-band polarization angle
54- 56 F3.1 deg e_PAJ [0.2/9]? PAJ 1σ error
58- 62 F5.1 deg PAH ? H-band polarization angle
64- 66 F3.1 deg e_PAH ? PAH 1σ error
68- 72 F5.1 deg PAKs ? Ks-band polarization angle
74- 76 F3.1 deg e_PAKs ? PAKs 1σ error
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Note (5): For sources with P/δP<3, the 3δP upper limits are listed.
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Byte-by-byte Description of file: names.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/314] Running sequence numbe
5- 53 A49 --- Name Individual names (from column "Note" of table1)
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Ref Reference code
16- 34 A19 --- BibCode Bibcode
36- 55 A20 --- Aut Author's name(s)
57-153 A97 --- Comm Comment
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 20-Feb-2013