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J/ApJ/849/157   Polarimetry obs. toward IC5146 background stars   (Wang+, 2017)

Multiwavelength stellar polarimetry of the filamentary cloud IC5146. I. Dust properties. Wang J.-W., Lai S.-P., Eswaraiah C., Clemens D.P., Chen W.-P., Pandey A.K. <Astrophys. J., 849, 157 (2017)> =2017ApJ...849..157W
ADC_Keywords: Polarization; Optical; Photometry, infrared; Extinction; Star Forming Region; Interstellar medium Keywords: dust, extinction ; ISM: clouds ; ISM: individual objects (IC5146) ; ISM: magnetic fields ; ISM: structure ; polarization Abstract: We present optical and near-infrared stellar polarization observations toward the dark filamentary clouds associated with IC5146. The data allow us to investigate the dust properties (this paper) and the magnetic field structure (Paper II). A total of 2022 background stars were detected in the Rc, i', H, and/or K bands to AV≲25mag. The ratio of the polarization percentage at different wavelengths provides an estimate of λmax, the wavelength of the peak polarization, which is an indicator of the small-size cutoff of the grain size distribution. The grain size distribution seems to significantly change at AV∼3mag, where both the average and dispersion of PRc/PH decrease. In addition, we found λmax∼0.6-0.9µm for AV>2.5mag, which is larger than the ∼0.55µm in the general interstellar medium (ISM), suggesting that grain growth has already started in low-AV regions. Our data also reveal that polarization efficiency (PE=Pλ/AV) decreases with AV as a power law in the Rc, i', and K bands with indices of -0.71±0.10, -1.23±0.10, and -0.53±0.09. However, H-band data show a power index change; the PE varies with AV steeply (index of -0.95±0.30) when AV<2.88±0.67mag, but softly (index of -0.25±0.06) for greater AV values. The soft decay of PE in high-AV regions is consistent with the radiative alignment torque model, suggesting that our data trace the magnetic field to AV∼20mag. Furthermore, the breakpoint found in the H band is similar to that for AV, where we found the PRc/PH dispersion significantly decreased. Therefore, the flat PE-AV in high-AV regions implies that the power-index changes result from additional grain growth. Description: We measured the polarization of background stars toward the IC5146 filamentary cloud system with several instruments: the Aryabhatta Research Institute of Observational Sciences (ARIES) Imaging Polarimeter (AIMPOL) and Triple-Range (g', r', i') Imager and POLarimeter (TRIPOL; at the Lulin Observatory) provided optical Rc- and i'-band polarimetry data, respectively. Mimir (at the Lowell Observatory Perkins Telescope) measured the H- and K-band polarizations at near-infrared wavelengths. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 380 48741 Measured polarization properties of stars probing the IC5146 dark cloud complex
See also: II/226 : Stellar polarization catalogs agglomeration (Heiles, 2000) II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007) VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006) VI/139 : Herschel Observation Log (Herschel Science Centre, 2013) II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016) J/ApJ/665/369 : Photopolarimetry of Southern Coalsack stars (Andersson+, 2007) J/A+A/502/845 : Dust coagulation in molecular clouds (Ormel+, 2009) J/ApJ/741/21 : Polarization of stars in Taurus (Chapman+, 2011) J/A+A/569/L1 : Polarization hole in a starless core (Alves+, 2014) J/ApJ/793/126 : L204 - Cloud 3 polarimetry and photometry (Cashman+, 2014) J/ApJ/833/176 : The magnetic field of L1544. I. NIR data (Clemens+, 2016) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 5 I5 -- Seq [1/48741] Polarimetric Catalog Star Number 7- 15 F9.5 deg RAdeg [325.7/328.9] Right Ascension (J2000) 17- 24 F8.5 deg DEdeg [46.5/48.5] Declination (J2000) 26- 32 F7.2 % QR [-2.6/4]?=-999 Normalized Stokes Q in Rc-band 34- 40 F7.2 % e_QR [0.02/0.8]?=-999 Uncertainty in QR 42- 48 F7.2 % UR [-3.3/6.3]?=-999 Normalized Stokes U in Rc-band 50- 56 F7.2 % e_UR [0.01/0.8]?=-999 Uncertainty in UR 58- 64 F7.2 % PR [0/6.4]?=-999 Debiased Rc-band polarization percentage 66- 72 F7.2 % e_PR [0.03/0.8]?=-999 Uncertainty in PR 74- 80 F7.2 deg PAR [0.6/180]?=-999 Rc-band Polarization Angle 82- 88 F7.2 deg e_PAR [0.3/75]?=-999 Uncertainty in PAR 90- 96 F7.2 % Qi [-3.7/6]?=-999 Normalized Stokes Q in i'-band 98-104 F7.2 % e_Qi [0.02/1]?=-999 Uncertainty in Qi 106-112 F7.2 % Ui [-2.4/6.6]?=-999 Normalized Stokes U in i'-band 114-120 F7.2 % e_Ui [0.02/1]?=-999 Uncertainty in Ui 122-128 F7.2 % Pi [0.5/6.6]?=-999 Debiased i'-band polarization percentage 130-136 F7.2 % e_Pi [0.02/1]?=-999 Uncertainty in Pi 138-144 F7.2 deg PAi [0.5/180]?=-999 i'-band Polarization Angle 146-152 F7.2 deg e_PAi [0.3/9.5]?=-999 Uncertainty in PAi 154-160 F7.2 % QH [-99.9/99.9]?=-999 Normalized Stokes Q in H-band 162-168 F7.2 % e_QH [0.08/99.9]?=-999 Uncertainty in QH 170-176 F7.2 % UH [-99.9/99.9]?=-999 Normalized Stokes U in H-band 178-184 F7.2 % e_UH [0.08/99.9]?=-999 Uncertainty in UH 186-192 F7.2 % PH [0/99.9]?=-999 Debiased H-band polarization percentage 194-200 F7.2 % e_PH [0.08/99]?=-999 Uncertainty in PH 202-208 F7.2 deg PAH [0/180]?=-999 H-band Polarization Angle 210-216 F7.2 deg e_PAH [1.3/180]?=-999 Uncertainty in PAH 218-224 F7.2 % QK [-95.3/99.9]?=-999 Normalized Stokes Q in K-band 226-232 F7.2 % e_QK [0.1/99.9]?=-999 Uncertainty in QK 234-240 F7.2 % UK [-99.1/89.5]?=-999 Normalized Stokes U in K-band 242-248 F7.2 % e_UK [0.1/99.9]?=-999 Uncertainty in UK 250-256 F7.2 % PK [0/99.9]?=-999 Debiased K-band polarization percentage 258-264 F7.2 % e_PK [0.1/99]?=-999 Uncertainty in PK 266-272 F7.2 deg PAK [0/180]?=-999 K-band Polarization Angle 274-280 F7.2 deg e_PAK [2.8/180]?=-999 Uncertainty in PAK 282-289 F8.3 mag Jmag [5.5/17.6]?=-999 2MASS J-band magnitude 291-298 F8.3 mag e_Jmag [0.007/2.3]?=-999 Uncertainty in Jmag 300-307 F8.3 mag Hmag [4.4/16.5]?=-999 2MASS H-band magnitude 309-316 F8.3 mag e_Hmag [0.007/1]?=-999 Uncertainty in Hmag 318-325 F8.3 mag Ksmag [3.9/16.3]?=-999 2MASS Ks-band magnitude 327-334 F8.3 mag e_Ksmag [0.005/0.8]?=-999 Uncertainty in Kmag 336-343 F8.3 mag W1mag [4/16.1]?=-999 WISE band 1 magnitude 345-352 F8.3 mag e_W1mag [0.02/0.5]?=-999 Uncertainty in W1mag 354-361 F8.3 mag W2mag [4/17.7]?=-999 WISE band 2 magnitude 363-370 F8.3 mag e_W2mag [0.01/0.6]?=-999 Uncertainty in W2mag 372-378 F7.2 mag Av [-3.7/28.8]?=-999 NICER extinction (1) 380 I1 -- UF [0/1] Usage Flag: 1=Selected for further analysis; 0=Not selected
Note (1): The uncertainties of Av are 0.93mag, estimated in Section 3.1.
History: From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 18-Jun-2018
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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