J/A+A/642/A118 Magnetized disk-halo transition region of M51 (Kierdorf+, 2020)
The magnetized disk-halo transition region of M51.
Kierdorf M., Mao S.A., Beck R., Basu A., Fletcher A., Horellou C.,
Tabatabaei F., Ott J., Haverkorn M.
<Astron. Astrophys. 642, A118 (2020)>
=2020A&A...642A.118K 2020A&A...642A.118K (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Magnetic fields
Keywords: galaxies: general - magnetic fields: galaxies -
galaxies: individual: M51 - galaxies: ISM
Abstract:
An excellent laboratory for studying large scale magnetic fields is
the grand design face-on spiral galaxy M51. Due to
wavelength-dependent Faraday depolarization, linearly polarized
synchrotron emission at different radio frequencies gives a picture of
the galaxy at different depths: Observations at L-band (1-2GHz) probe
the halo region while at C- and Xband (4-8GHz) the linearly polarized
emission probe the disk region of M51. We present new observations of
M51 using the Karl G. Jansky Very Large Array (VLA) at S-band
(2-4GHz), where previously no polarization observations existed, to
shed new light on the transition region between the disk and the halo.
We discuss a model of the depolarization of synchrotron radiation in a
multilayer magneto-ionic medium and compare the model predictions to
the multi-frequency polarization data of M51 between 1-8GHz. The new
S-band data are essential to distinguish between different models. Our
study shows that the initial model parameters, i.e. the total regular
and turbulent magnetic field strengths in the disk and halo of M51,
need to be adjusted to successfully fit the models to the data.
Description:
M51 JVLA S-band images.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 215 10 List of fits files
fits/* . 10 Individual fits files
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See also:
J/A+A/568/A74 : Low-frequency (115-175MHz) image of M51 (Mulcahy+, 2014)
J/A+A/592/A123 : M51 total intensity image at 333MHz (Mulcahy+, 2016)
J/A+A/593/A118 : HCN(1-0) cube for the nucleus of M51 (Querejeta+, 2016)
J/A+A/617/A136 : LOFAR M51 field low-frequency polarized sources
(Horellou+, 2018)
J/A+A/625/A19 : 33 GHz continuum map of M51 (Querejeta+, 2019)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 I4 --- Nx Number of pixels along X-axis
25- 28 I4 --- Ny Number of pixels along Y-axis
30- 51 A22 "datime" Obs.date Observation date
53- 59 F7.5 GHz Freq ? Observed frequency
61- 64 I4 Kibyte size Size of FITS file
66-102 A37 --- FileName Name of FITS file, in subdirectory fits
104-215 A112 --- Title Title of the FITS file
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Acknowledgements:
Rainer Beck, rbeck(at)mpifr-bonn.mpg.de
(End) Patricia Vannier [CDS] 30-Jun-2020