J/ApJS/201/13 Submm polarization of Galactic clouds (Vaillancourt+, 2012)
Submillimeter polarization of Galactic clouds: a comparison of 350µm and
850µm data.
Vaillancourt J.E., Matthews B.C.
<Astrophys. J. Suppl. Ser., 201, 13 (2012)>
=2012ApJS..201...13V 2012ApJS..201...13V
ADC_Keywords: Polarization ; Molecular clouds ; Interstellar medium ;
Millimetric/submm sources
Keywords: dust, extinction - ISM: clouds - polarization - submillimeter: ISM
Abstract:
The Hertz and SCUBA polarimeters, working at 350um and 850um,
respectively, have measured the polarized emission in scores of
Galactic clouds. Of the clouds in each data set, 17 were mapped by
both instruments with good polarization signal-to-noise ratios. We
present maps of each of these 17 clouds comparing the dual-wavelength
polarization amplitudes and position angles at the same spatial
locations.
Description:
We have compiled all the spatially coincident data available from the
Hertz (350um; Dotson et al. 2010, Cat. J/ApJS/186/406) and SCUBA
(850um; Matthews et al. 2009, Cat. J/ApJS/182/143) polarimeters. In
order to facilitate this comparison the SCUBA-pol data have been
spatially re-sampled to match the spatial locations of the Hertz data;
the two instruments have comparable spatial resolution (20"). We
find a total of 1699 individual locations which can be compared within
17 different Galactic clouds.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 55 18 Object summary and polarization ratios
table2.dat 171 1699 Intensity and polarization data on a grid of points
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See also:
J/ApJS/186/406 : 350um polarimetry from CSO (Dotson+, 2010)
J/ApJS/182/143 : SCUPOL Legacy polarimetry of SCUBA (Matthews+, 2009)
J/AJ/138/1380 : Dust clumps in the Galactic Plane (Matthews+, 2009)
J/MNRAS/379/663 : 850um observations of W3 giant molecular cloud (Moore+, 2007)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Source designation
16 A1 --- n_Name [def] Note about individual sources (1)
18- 20 I3 --- Tot Total number of points common to both the 350 and
850um data sets
22- 24 I3 --- Ntot1 Number of data points from the "Total" column
satisfying Pc>0 (2)
26- 28 F3.1 --- Med1 Median polarization ratios (P[850]/P[350]) (2)
30- 32 F3.1 --- MAD1 Median absolute deviation (2)
34- 36 I3 --- Ntot2 Number of data points from the "Total" column
satisfying Pc≥3σ(3)
38- 40 F3.1 --- Med2 ? Median polarization ratios (P[850]/P[350]) (3)
42- 44 F3.1 --- MAD2 ? Median absolute deviation (3)
46- 47 I2 --- Ntot3 Number of data points from the "Total" column also
satisfying |{D}Φ|<10° (4)
49- 51 F3.1 --- Med3 ? Median polarization ratios (P[850]/P[350]) (4)
53- 55 F3.1 --- MAD3 ? Median absolute deviation (4)
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Note (1): Flag as follows:
d = IRAS 06382+0939
e = All data in DR 21, including DR 21 (Main).
f = G49.5-0.4
Note (2): "Pc>0" indicates regions where the measured data satisfy
Pm/σp>20.5 at both wavelengths (see Section 2.2).
Note (3): "Pc≥3σp" indicate only data points satisfying that
signal-to-noise criterion at both wavelengths; these values are
calculated after applying the de-biasing technique discussed in
Section 2.2.
Note (4): "also |ΔΦ|<10°" satisfy both the latter P/σp
constraint as well as the additional ΔΦ criterion.
ΔΦ=Φ(850)-Φ(350), where Φ refers to the
polarization position angle at the noted wavelength.
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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- 15 A15 --- Name Object name (1)
17- 20 I4 arcsec oRA Right Ascension offset from center (2)
22- 25 I4 arcsec oDec Declination offset from center (2)
27- 31 F5.2 % P350 [0/65.42] Polarization magnitude at 350um (3)
33- 40 F8.2 % e_P350 Uncertainty in P350 (3)
42- 46 F5.1 deg PA350 [0.1/180] Polarization angle at 350um (3)
48- 53 F6.1 deg e_PA350 Uncertainty in PA350 (3)
55- 60 F6.2 % P850 [0/408.59] Polarization magnitude at 850um (4)
62- 69 F8.2 % e_P850 Uncertainty in P850 (4)
71- 75 F5.1 deg PA850 [-89.9/89.9] Polarization angle at 850um (3)
77- 81 F5.1 deg e_PA850 Uncertainty in PA850 (4)
83- 91 E9.2 Jy F350 [-2.55/2100] Source intensity at 350um; Jy/beam
93-100 E8.2 Jy e_F350 Uncertainty in F350
102-110 E9.2 Jy F850 [-7.21/171] Source intensity at 850um; Jy/beam
112-119 E8.2 Jy e_F850 Uncertainty in F850
121-126 F6.2 --- Pratio [0/322.85]? Ratio of P850-to-P350; P850/P350 (5)
128 A1 --- f_Pratio [NI] Flag on PRatio (I=Inf; N=NaN) (5)
130-137 F8.2 --- e_Pratio ? Uncertainty in PRatio
139-143 F5.1 deg dPA [-89.9/90] Difference PA850-PA350
145-150 F6.1 deg e_dPA Uncertainty in dPA
152-160 E9.2 --- Fratio [-1.83/0.647]? Ratio F850/F350
162 A1 --- f_Fratio [I] Flag on Fratio (I=Inf; N=NaN)
164-171 E8.2 --- e_Fratio ? Uncertainty in Fratio
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Note (1): IRAS 16293+2422 is a misprint for IRAS 16293-2422; corrected at CDS.
Note (2): Object centers are given in Table 1 of Dotson et al.
(2010, Cat. J/ApJS/186/406).
Note (3): Polarization magnitude data at 350um (from Dotson et al. 2010,
Cat. J/ApJS/186/406) are corrected for positive bias. No corrections
are made to the polarization angle, nor to any of the uncertainties.
(See Section 2.2 of the text.)
Note (4): Polarization magnitude data at 850um have already been corrected
for positive bias by Matthews et al. (2009, Cat. J/ApJS/182/143). No
corrections are made to the polarization angle, nor to any of the
uncertainties. (See Section 2.2 of the text.)
Note (5): The ratio P(850)/P(350) is reported as NaN for cases in which the
best (bias corrected) estimates are P(850)=P(350)=0, Inf for
cases in which only P(350)=0, and equal to zero when only P(850)=0.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 08-Oct-2012