J/ApJ/688/1029 Magnetic field in the SMC (Mao+, 2008)
A radio and optical polarization study of the magnetic field in the Small
Magellanic Cloud.
Mao S.A., Gaensler B.M., Stanimirovic S., Haverkorn M.,
McClure-Griffiths N.M., Staveley-Smith L., Dickey J.M.
<Astrophys. J., 688, 1029-1049 (2008)>
=2008ApJ...688.1029M 2008ApJ...688.1029M
ADC_Keywords: Magellanic Clouds ; Magnetic fields ; Polarization ;
Radio continuum
Keywords: magnetic fields - polarization - Magellanic Clouds
Abstract:
We present a study of the magnetic field of the Small Magellanic Cloud
(SMC), carried out using radio Faraday rotation and optical starlight
polarization data. Consistent negative rotation measures (RMs) across
the SMC indicate that the line-of-sight magnetic field is directed
uniformly away from us with a strength 0.19±0.06µG. Applying the
Chandrasekhar-Fermi method to starlight polarization data yields an
ordered magnetic field in the plane of the sky of strength 1.6±0.4uG
oriented at a position angle 4±12°, measured counterclockwise
from the great circle on the sky joining the SMC to the Large
Magellanic Cloud (LMC). We construct a three-dimensional magnetic
field model of the SMC, under the assumption that the RMs and
starlight polarization probe the same underlying large-scale field.
further test the pan-Magellanic field hypothesis.
Description:
RM data were acquired at the Australia Telescope Compact Array (ATCA)
over the period 2004 July 10-18, using the 6A array configuration
spanning baselines from 336.7 to 5938.8m, with a total of 32 adjacent
frequency channels each of bandwidth 4MHz centered on 1384MHz.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 45 70 Rotation measures of extragalactic sources in
the observed field
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See also:
VII/6 : Polarization of Extragalactic Radio Sources (Eichendorf+ 1980)
J/MNRAS/335/1085 : ATCA SMC Radio Continuum Source. I. (Filipovic+, 2002)
J/MNRAS/355/44 : ATCA SMC Radio Continuum Source. II. (Payne+, 2004)
J/ApJ/663/258 : Rotation measures of extragalactic sources in SGPS (Brown+,
2007)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID Source sequence number identification
(<[MGS2008] NNN> in Simbad) (1)
4 A1 --- f_ID [*] * means source behind the SMC
6- 7 I2 h RAh Hour of right ascension (J2000)
9- 10 I2 min RAm Minute of right ascension (J2000)
12- 16 F5.2 s RAs Second of right ascension (J2000)
18 A1 --- DE- Declination sign (J2000)
19- 20 I2 deg DEd Degree of declination (J2000)
22- 23 I2 arcmin DEm Arcminute of declination (J2000)
25- 29 F5.2 arcsec DEs Arcsecond of declination (J2000)
31- 34 I4 rad/m2 RM Rotation measure
36- 37 I2 rad/m2 e_RM RM uncertainty
39- 42 I4 rad/m2 RM2 ? Rotation measure after foreground RM
substraction (for sources behind the SMC (table
4 of the paper))
44- 45 I2 rad/m2 e_RM2 ? RM2 uncertainty
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Note (1): Missing source names are polarized sources identified by the
SFIND source finding algorithm which do not correspond to real sources
in Stokes I image.
Objects 0198 and 0208 of table 3 are a misprint for objects 019 and
020, respectively, of table 4; corrected at CDS.
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 18-Jan-2011