J/A+A/559/A27 RM Synthesis of 33 sources around M31 (Giessubel+, 2013)
Polarized synchrotron radiation from the Andromeda galaxy M31 and background
sources at 350 MHz.
Giessubel R., Heald G., Beck R., Arshakian T.G.
<Astron. Astrophys. 559, A27 (2013)>
=2013A&A...559A..27G 2013A&A...559A..27G
ADC_Keywords: Galaxies, nearby ; Radio sources ; Polarization
Keywords: instrumentation: interferometers - techniques: polarimetric -
galaxies: individual: M31 - galaxies: magnetic fields -
radio continuum: galaxies
Abstract:
Low-frequency radio continuum observations are best suited to search
for radio halos of inclined galaxies. Polarization measurements at low
frequencies allow the detection of small Faraday rotation measures
caused by regular magnetic fields in galaxies and in the foreground of
the Milky Way.
The detection of low-frequency polarized emission from a spiral galaxy
such as M31 allows us to assess the degree of Faraday depolarization,
which can be compared with models of the magnetized interstellar
medium.
Description:
The nearby spiral galaxy M31 was observed in two overlapping pointings
with the Westerbork Synthesis Radio Telescope (WSRT), resulting in
about 4' resolution in total intensity and linearly polarized
emission. The frequency range 310-376MHz was covered by 1024 channels,
which allowed the application of RM Synthesis on the polarization
data. We derived a data cube in Faraday depth. A catalogue of 33
polarized sources and their Faraday rotation in the M31 field is
presented.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
objects.dat 45 33 Source positions and names
FDclean.fit 2880 267582 RM Synthesis data FITS datacude
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See also:
J/A+AS/61/451 : The 37W catalogue of radio sources in M31 (Walterbos+ 1985)
J/ApJS/155/89 : 325MHz radio survey in M31 (Gelfand+, 2004)
J/ApJS/159/242 : 325MHz radio survey in M31. II. (Gelfand+, 2005)
Byte-by-byte Description of file: objects.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Names Source name(s)
16- 18 I3 pix xpos x position in FITS cube
20- 22 I3 pix ypos y position in FITS cube
24- 25 I2 h RAh Right ascension (B1950)
27- 28 I2 min RAm Right ascension (B1950)
30- 33 F4.1 s RAs Right ascension (B1950)
35 A1 --- DE- Declination sign (B1950)
36- 37 I2 deg DEd Declination (B1950)
39- 40 I2 arcmin DEm Declination (B1950)
42- 45 F4.1 arcsec DEs Declination (B1950)
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Acknowledgements:
Rene Giessubel, rgiess(at)mpifr-bonn.mpg.de,
Max-Planck-Institut fur Radioastronomie, Bonn
History:
* 31-Oct-2013 : On-line version
* 31-Jan-2015 : Equinox corrected into B1950
(End) R. Giessubel [Max-Planck-Inst., Bonn], P. Vannier [CDS] 17-Sep-2013