J/A+A/632/A13 NGC 4013 radio and polarization maps (Stein+, 2019)
CHANG-ES XIX. Galaxy NGC 4013: a diffusion-dominated radio halo with
plane-parallel disk and vertical halo magnetic fields.
Stein Y., Dettmar R.-J., Wezgowiec M., Irwin J., Beck R., Wiegert T.,
Krause M., Li J.-T., Heesen V., Miskolczi A., MacDonald S., English J.
<Astron. Astrophys. 632, A13 (2019)>
=2019A&A...632A..13S 2019A&A...632A..13S (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies ; Radio continuum ; Magnetic fields ; Polarization
Keywords: diffusion - X-rays: galaxies - galaxies: halos -
galaxies: individual: NGC 4013 - galaxies: magnetic fields -
radio continuum: galaxies
Abstract:
From the Continuum HAloes in Nearby Galaxies - an EVLA Survey
(CHANG-ES) radio continuum data from the Karl G. Jansky Very Large
Array (VLA), observed in two frequency bands, 6GHz (C-band) and 1.5GHz
(L-band), we present the radio maps, including polarization of the
edge-on spiral galaxy NGC 4013. Supplemantary X-ray data are also
presented here.
The central point source of NGC 4013 dominates the radio continuum
emission in both CHANG-ES bands. Complementary X-ray data from Chandra
show one dominant point source in the central part. The XMM-Newton
spectrum shows hard X-rays, but no clear AGN classification is
possible at this time. The radio continuum halo of NGC 4013 in C-band
is rather small, while the low-frequency LOFAR data reveal a large
halo. The scale height analysis shows that Gaussian fits better
represent the intensity profiles than do exponential fits. The
frequency dependence gives clear preference to diffusive CRE
transport. The radio halo of NGC 4013 is relatively faint. Diffusion
is the dominating transport process up to heights of 1-2kpc. The
polarization data reveal plane-parallel, regular magnetic fields
within the entire disk and vertical halo components indicating the
presence of an axisymmetric field having a radial component pointing
outwards. The mean magnetic field strength of the disk of NGC 4013 of
6.6µG is rather small. Large-scale vertical fields are observed in
the halo out to heights of about 6kpc.
The interaction and the low star formation rate (SFR) across the disk
of NGC 4013 probably influence the appearance of its radio continuum
halo and are correlated with the low total magnetic field strength.
Several observable quantities give consistent evidence that the CR
transport in the halo of NGC 4013 is diffusive: the frequency
dependence of the synchrotron scale height, the disk/halo flux density
ratio, the vertical profile of the synchrotron spectral index, the
small propagation speed measured modeled with spinnaker, and the low
temperature of the X-ray emitting hot gas.
Description:
We present the radio and polarization data as well as the XMM-Newton
data of NGC 4013 in fits-format named in correspondence to the figure
in the paper:
1. JVLA-CHANG-ES data: 6cm (Stokes I, polarized intensity (PI),
polarisation angle (PA))
2. JVLA-CHANG-ES data: 20cm (Stokes I)
3. XMM-Newton EPIC emission in the energy band 0.2-1keV
Please see paper Stein et al. 2019b and Irwin et al.
(2012AJ....144...43I 2012AJ....144...43I, 2012AJ....144...44I 2012AJ....144...44I) for details on the
calibration and imaging.
Objects:
-------------------------------------------------
RA (2000) DE Designation(s)
-------------------------------------------------
11 58 31.42 +43 56 49.3 NGC 4013 = UGC 6963
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 253 7 List of fits files
fits/* . 7 Individual fits files
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See also:
J/A+A/623/A33 : NGC 4666 polarization maps (Stein+, 2019)
J/A+A/632/A10 : NGC 4631 total intensity images (Mora-Partiarroyo+, 2019)
J/A+A/632/A11 : Radio images of NGC 4631 (Mora-Partiarroyo+, 2019)
J/A+A/632/A12 : NGC 891 and NGC 4565 radio images (Schmidt+, 2019)
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 22 I3 --- Nx Number of pixels along X-axis
24- 26 I3 --- Ny Number of pixels along Y-axis
28- 46 A19 "datime" Obs.date Observation date
48- 51 I4 Kibyte size Size of FITS file
53-106 A54 --- FileName Name of FITS file, in subdirectory fits
108-253 A146 --- Title Title of the FITS file
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Acknowledgements:
Yelena Stein, yelena.stein(at)astro.unistra.fr
References:
Irwin et al., Paper I 2012AJ....144...43I 2012AJ....144...43I
Irwin et al., Paper II 2012AJ....144...44I 2012AJ....144...44I
Irwin et al., Paper III 2013AJ....146..164I 2013AJ....146..164I
Wiegert et al., Paper IV 2015AJ....150...81W 2015AJ....150...81W
Irwin et al., Paper V 2015ApJ...809..172I 2015ApJ...809..172I
Li et al., Paper VI 2016MNRAS.456.1723L 2016MNRAS.456.1723L
Damas-Segovia et al., Paper VII 2016ApJ...824...30D 2016ApJ...824...30D
Irwin et al., Paper VIII 2017MNRAS.464.1333I 2017MNRAS.464.1333I
Krause et al., Paper IX 2018A&A...611A..72K 2018A&A...611A..72K
Vargas et al., Paper X 2018ApJ...853..128V 2018ApJ...853..128V
Irwin et al., Paper XI 2018MNRAS.476.5057I 2018MNRAS.476.5057I
Miskolczi et al., Paper XII 2019A&A...622A...9M 2019A&A...622A...9M
Stein et al., Paper XIII 2019A&A...623A..33S 2019A&A...623A..33S, Cat. J/A+A/623/A33
Mora Partiarroyo et al., Paper XIV 2019A&A...632A..10M 2019A&A...632A..10M, Cat. J/A+A/632/A10
Mora Partiarroyo et al., Paper XV 2019A&A...632A..11M 2019A&A...632A..11M, Cat. J/A+A/632/A11
Schmidt et al., Paper XVI 2019A&A...632A..12S 2019A&A...632A..12S, Cat. J/A+A/632/A12
Vargas et al., Paper XVII 2019ApJ...881...26V 2019ApJ...881...26V
Irwin et al., Paper XX 2019AJ....158...21I 2019AJ....158...21I
(End) Patricia Vannier [CDS] 07-Oct-2019