J/A+A/665/A64 NGC 628 (M 74) radio and X-ray maps images (Wezgowiec+, 2022)
Hot magnetic halo of NGC 628 (M 74).
Wezgowiec M., Beck R. Hanasz M., Soida M., Ehle M., Dettmar R.-J.,
Urbanik M.
<Astron. Astrophys. 665, A64 (2022)>
=2022A&A...665A..64W 2022A&A...665A..64W (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Magnetic fields ; Radio sources ; X-ray sources
Keywords: galaxies: individual: NGC 628 - galaxies: ISM - galaxies: spiral -
galaxies: magnetic fields - magnetic reconnection
Abstract:
In several spiral galaxies that are observed face-on, large-scale
ordered magnetic fields (the so-called magnetic arms) were found. One
of the explanations was the action of the magnetic reconnection, which
leads to a higher ordering of the magnetic fields. Because it
simultaneously converts the energy of the magnetic fields into thermal
energy of the surroundings, magnetic reconnection has been considered
as a heating mechanism of the interstellar medium for many years.
Until recently, no clear observational evidence for this phenomenon
was found.
We search for possible signatures of gas heating by magnetic
reconnection effects in the radio and X-ray data for the face-on
spiral galaxy NGC 628 (M 74), which presents pronounced magnetic
arms and evidence for vertical magnetic fields.
The strengths and energy densities of the magnetic field in the spiral
and magnetic arms were derived, as were the temperatures and thermal
energy densities of the hot gas, for the disk and halo emission. In
the regions of magnetic arms, higher order and lower energy density of
the magnetic field is found than in the stellar spiral arms. The
global temperature of the hot gas is roughly constant throughout the
disk. The comparison of the findings with those obtained for the
starburst galaxy M 83 suggests that magnetic reconnection heating may
be present in the halo of NGC 628. The joint analysis of the
properties of the magnetic fields and the hot gas in NGC 628 also
provided clues for possible tidal interaction with the companion
galaxy.
Description:
We present the radio and X-ray data for M74 in FITS format (m74_):
1. VLA data: 6cm - total power (I), polarised intensity (PI),
polarisation angle (PA)
2. XMM-Newton EPIC emission in the energy band 0.2-1 keV (xsf)
3. XMM-Newton EPIC emission in the energy band 1-2keV (xmd)
4. XMM-Newton EPIC hardness ratio map between the energy bands
0.2-1 and 1-2keV (HR)
5. XMM-Newton OM image in UVW1 filter (UV)
Objects:
-----------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------
01 36 41.75 +15 47 01.1 M74 = NGC 628
-----------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 148 7 List of fits maps
fits/* . 7 Individual fits maps
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See also:
J/A+A/600/A6 : NGC628 3.1GHz total intensity + polarised images (Mulcahy+ 2017)
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- 39 A10 "datime" Obs.date Observation date
41- 47 F7.5 GHz Freq ? Observed frequency
49- 53 I5 Kibyte size Size of FITS file
55- 66 A12 --- FileName Name of FITS file, in subdirectory fits
68-148 A81 --- Title Title of the FITS file
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Acknowledgements:
Marek Wezgowiec, markmet(at)oa.uj.edu.pl
(End) Patricia Vannier [CDS] 25-Jul-2022