J/MNRAS/512/5755 Radio/X-ray sources of 35 CHANG-ES galaxies (Irwin+, 2022)
CHANG-ES - XXVII. A radio/X-ray catalogue of compact sources in and around
edge-on galaxies.
Irwin J., Dyer J., Drake L., Wang Q.D., Stil J., Stein Y., English J.,
Wiegert T.
<Mon. Not. R. Astron. Soc. 512, 5755-5770 (2022)>
=2022MNRAS.512.5755I 2022MNRAS.512.5755I (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Radio sources ; X-ray sources ; Photometry ;
Positional data
Keywords: catalogues - galaxies: nuclei - radio continuum: galaxies -
X-rays: galaxies
Abstract:
We present catalogues of discrete, compact radio sources in and around
the discs of 35 edge-on galaxies in the Continuum Halos in Nearby
Galaxies - an EVLA Survey. The sources were extracted using the pybdsf
program at both 1.6 GHz (L band) and 6.0 GHz (C band) from matching
resolution (~=3 arcsec) data. We also present catalogues of X-ray
sources from Chandra data sets for 27 of the galaxies. The sources at
the two radio frequency bands were positionally cross- correlated with
each other, and the result cross-correlated with the X-ray sources.
All catalogues are included for download with this paper. We detect a
total of 2507 sources at L band and 1413 sources at C band. 75 sources
have been successfully cross-correlated in both radio bands plus
X-ray. Three new nuclear sources are candidates for low luminosity
active galactic nuclei in NGC 3877, NGC 4192, and NGC 5792; the one in
NGC 3877 also appears to be variable. We also find new nuclear sources
in two companion galaxies: NGC 4435 (companion to NGC 4438) and NGC 4298
(companion to NGC 4302). We have also discovered what appears to
be a foreground double star; each star has X-ray emission and there is
radio emission at both L band and C band in between them. This could
be a colliding wind binary system. Suggestions for follow-up studies
are offered.
Description:
In this work, we present a radio continuum and X-ray catalogue of
discrete sources in and around a sample of nearby edge-on galaxies.
All galaxies in this sample are from the CHANG-ES program obtained
with the VLA. The X-ray data were obtained using the Chandra X-ray
satellite. This new catalogue represents the first systematic
investigation of discrete radio/X-ray sources in such galaxies.
For radio observations Irwin et al. (2019Galax...7...42I 2019Galax...7...42I), this study
consist of B-configuration, L band and approximately matching
resolution of C-configuration, C band. We extract radio compact source
with PYBDSF from 35 galaxy maps images based on rms level method (i.e
section 2.2). We obtained results from gaussian fits and presented it
in c-band.dat for 1413 sources and l-band.dat for 2506 sources. Next,
we proceed to chandra x-ray sources extraction from 27 of 35 galaxies
(i.e section 2.3). Source detection was performed with the WAVEDETECT
tool, we regroup these results in x-ray.dat for 2198 x-ray sources
detected on the four x-band bands (soft, medium, hard and broad), (i.e
section 3).
Also as explained in section 3.2, we cross-matched radio sources
between L and C band providing a total of 723 sources found to be
positionally matched at both bands over all 35 galaxies. These
cross-matches are further used to compute radio spectral indexes. We
show these work in the table crosslc.dat.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
galaxy.dat 21 35 CHANG-ES galaxies host sources sample
c-band.dat 565 1413 Extracted galactic radio sources in VLA obs
C-configuration and C-band observations at
6.0 GHz with a 2 GHz bandwidth
l-band.dat 565 2506 Extracted galactic radio sources in VLA obs
B-configuration and L-band observations at
1.6 GHz using a 500 MHz bandwidth
crosslc.dat 182 723 Cross-matching results of radio sources between
L band and C band
x-ray.dat 347 2198 Extracted galactic x-ray sources with Chandra
imaging observations in soft, medium, hard and
broad x-ray bands for 27 of 35 galaxies
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See also:
J/A+A/622/A4 : LOFAR observations XMM-LSS field (Hale+, 2019)
J/MNRAS/460/2385 : Bootes field LOFAR 150-MHz observations (Williams+, 2016)
J/ApJ/793/82 : LOFAR Bootes and 3C295 field sources (van Weeren+, 2014)
J/AJ/150/81 : CHANG-ES. IV. VLA D-configuration observations
(Wiegert+, 2015)
J/A+A/670/A158 : CHANG-ES. XXVI. radio images of 5 galaxies (Stein+, 2023)
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)
J/A+A/632/A13 : NGC 4013 radio and polarization maps (Stein+, 2019)
J/A+A/639/A111 : NGC 4217 radio and polarization maps (Stein+, 2020)!
Byte-by-byte Description of file: galaxy.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Galaxy Galaxy host source name (galaxy)
11- 13 I3 --- Nc Number of sources detected in radio C-band
15- 17 I3 --- Nl Number of sources detected in radio L-band
19- 21 I3 --- Nx Number of sources detected in x-ray bands
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Byte-by-byte Description of file: c-band.dat l-band.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Galaxy Galaxy host source name (galaxy)
11- 13 I3 --- ID Relative galaxy compact source
identification number (Source_id) (1)
15- 17 I3 --- IDisl Relative island galaxy compact source
identification number (Isl_id) (1)
19- 35 F17.13 deg RAdeg Right ascension (J2000) (RA)
37- 52 E16.14 deg e_RAdeg Error 1σ of RAdeg (E_RA)
54- 72 F19.14 deg DEdeg Declination (J2000) (DEC)
74- 89 E16.14 deg e_DEdeg Error 1σ of DEdeg (E_DEC)
91-105 F15.8 uJy I Integrated Stokes I gaussian flux
density (Total_flux) (2)
107-119 F13.8 uJy e_I Mean error of I (ETotalflux) (2)
121-135 F15.8 uJy/beam Ipeak Value of the gaussian flux density at
the location of the source maximum
(Peak_flux) (2)
137-148 F12.8 uJy/beam e_Ipeak Mean error of Ipeak (EPeakflux) (2)
150-166 F17.13 deg RAmdeg Right ascension at the location of the
source maximum (RA_max)
168-183 E16.14 deg e_RAmdeg Error 1σ of RAmaxdeg (ERAmax)
185-202 F18.14 deg DEmdeg Declination at the location of the
source maximum (DEC_max)
204-219 E16.14 deg e_DEmdeg Error 1σ of DEmaxdeg (EDECmax)
221-236 F16.12 arcsec MajAxis FWHM of the source major axis (Maj)
238-252 F15.12 arcsec e_MajAxis Mean error of MajAxis (E_Maj)
254-268 F15.12 arcsec MinAxis FWHM of the source minor axis (Min)
270-283 F14.12 arcsec e_MinAxis Mean error of MinAxis (E_Min)
285-302 F18.14 deg PA Major axis position angle (PA)
304-321 F18.14 deg e_PA Mean error of PA (E_PA)
323-338 F16.12 arcsec DCMajAxis FWHM of the deconvolved source major
axis (DC_Maj) (3)
340-354 F15.12 arcsec e_DCMajAxis Mean error of DCMajAxis (EDCMaj)
356-370 F15.12 arcsec DCMinAxis FWHM of the deconvolved source minor
axis (DC_Min) (3)
372-385 F14.12 arcsec e_DCMinAxis Mean error of DCMinAxis (EDCMin)
387-404 F18.14 deg DCPA Deconvolved major axis position angle
(DC_PA) (3)
406-423 F18.14 deg e_DCPA Mean error of DCPA (EDCPA)
425-439 F15.8 uJy Iisl Integrated total flux of the island
within which the source is located
(IslTotalflux)
441-453 F13.8 uJy e_Iisl Mean error of Iisl (EIslTotal_flux)
455-466 F12.8 uJy/beam BkgRMS The original island background rms value
computed using the sliding box method
(Isl_rms)
468-479 F12.8 uJy/beam BkgMean The original island background mean
value computed using the sliding box
method (Isl_mean)
481-492 F12.8 uJy/beam BkgResRMS Average island residual background rms
after subtracting all sources in the
island (ResidIslrms)
494-505 F12.8 uJy/beam BkgResMean Average residual background mean after
subtracting all sources in the island
(ResidIslmean)
507-524 F18.15 arcmin Dist Angular distance of the source from the
galaxy centre computed from RAdeg and
DEdeg using a standard spherical
coordinate system (Disttocenter)
526-544 F19.15 deg Ang Corresponding angle measuring
counterclockwise from x=0
(Anglefromx=0) (4)
546-563 F18.15 --- PB ? Primary beam attenuation correction
factor at the position of the centre of
the source (PBcorrfactor) (5)
565 A1 --- Scode Structure code of the source (S_Code) (6)
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Note (1): As described in the section 2.2 Radio source extraction, it then
identifies 'islands' which are regions of contiguous emission that
are above a user-specified threshold. For this work, we accept an
island if all contiguous points are more than 3 times the local rms,
above the local mean value. PYBDSF algo then fits Gaussians to sources
within the island that meet another user-specified threshold. In this
work, a source is fit with a Gaussian if it is more than 5 times the
rms value above the mean.
Note (2): These values are uncorrected for the primary beam PB.
Note (3): Refer to the source after the synthesized beam has been deconvolved.
A zero means that the source is unresolved.
Note (4): A source at 90 degrees would be due north from the galaxy centre and
a source at 270 degrees would be due south. These columns are
introduced to help guide the eye when comparing sources in the
catalogues to the maps shown in Appendices.
Note (5): Primary beam (PB) attenuation at the position of the centre of the
source. All listed fluxes should be divided by this factor to correct
for PB attenuation. The PB weighting indicate that a typical error in
this factor is 0.5 per cent in both bands. This error does not take
into account systematic errors that may be present due to departures
from the assumption that the PB is spherically symmetric. The mapping
parameters used for CHANG-ES could result in larger PB errors that
increase with distance from the map centre. These start to depart from
the 0.5 per cent quoted above once PB falls below 0.85. In the range,
0.85 => PB => 0.60, the error steadily increases from
0.5 to 1.5 per cent, and in the range, 0.60 => PB => 0.11, the error
increases to 6.3 per cent. Once PB falls below 0.11, the PB correction
is unreliable. In C-band, eight galaxies were observed in two
different pointings for which the primary beams overlapped. For these
galaxies (NGC 891, NGC 3628, NGC 4244, NGC 4565, NGC 4594, NGC 4631,
NGC 5084, and NGC 5907), the PB column contains the value determined
from the combined, weighted PB map applicable to the galaxy in
question. An empty cell means that the position falls outside of the
20 per cent level of the combined beam.
Note (6): Structure codes of the source are as follows:
S = Indicates an isolated source that is fitted with a single
Gaussian, 1240 sources in c-band and 2316 sources in l-band
sample
M = Indicates a source that is extended and has been fitted with
multiple Gaussians, 171 sources in c-band and 190 sources
in l-band sample
C = Indicates a source that is fitted with a single Gaussian but
is within an island of emission that also contains other sources,
5 sources in c-band and 0 source in l-band sample
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Byte-by-byte Description of file: crosslc.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Galaxy Galaxy host source name (galaxy)
11- 13 I3 --- IDlc Unique L-band/C-band cross-match
identification number (LC_id)
15- 17 I3 --- IDl Unique source identification number from
l-band.dat (Source_idL)
19- 20 I2 --- IDc Unique source identification number from
c-band.dat (Source_idC)
22- 36 F15.8 uJy ILcor I corrected with primary beam I/PB in L band
(Flux_corL) (1)
38- 55 F18.13 uJy e_ILcor Mean error of ILcor (EfluxcorL-band) (1)
57- 71 F15.8 uJy ICcor ? I corrected with primary beam I/PB in C
band (Flux_corC) (1)
73- 91 F19.14 uJy e_ICcor ? Mean error of ICcor (EfluxcorC-band) (1)
93-104 F12.9 --- Sp ? The spectral index computed with the
equation 1 of the section 3.2 (Spectralindex)
(2)
106-122 F17.15 --- e_Sp ? Propagated error of Sp (E_SpIn) (2)
124-134 F11.9 arcmin DistL Angular distance Dist from l-band.dat
(DisttocenterL)
136-146 F11.9 arcmin DistC Angular distance Dist from c-band.dat
(DisttocenterC)
148-160 F13.9 deg AngL Corresponding angle Ang from l-band.dat
(Anglefromx=0L)
162-174 F13.9 deg AngC Corresponding angle Ang from c-band.dat
(Anglefromx=0C)
176-182 A7 --- Nuclear Indicates if the source is closed from the
centre of the galaxy (Nuclear?) (3)
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Note (1): If the PB correction falls below 0.11, the flux density becomes
unreliable, so the cell is left blank. The error in the flux density
includes the error as computed by PYBDSF plus the error in the primary
beam plus 1 per cent to allow for a calibration error, all added in
quadrature.
Note (2): The equation 1 is expressed as ILcor/ICcor = (νL/νC)^α
where νL and νC are centre frequencies in each bands.
The error e_Sp = |ln(νL/νC)|-1 *
SQRT[(e_ILcor/ILcor)2 + (e_ICcor/ICcor)2].
Note (3): Any source that is within 3 arcsec in spatial resolution from the
centre of the galaxy.
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Byte-by-byte Description of file: x-ray.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Galaxy Galaxy host source name (galaxy)
9- 11 I3 --- ID Unique source identification number from the
WAVEDETECT tool output (ID)
13- 29 F17.13 deg RAdeg Right ascension (J2000) (RA)
31- 49 F19.15 deg DEdeg Declination (J2000) (DEC)
51- 67 F17.15 arcsec ePos Positional uncertainty (delta_x) (1)
69- 88 F20.15 ct CtS ? The total X-ray photon counts detected in
soft band 0.3-1.2 keV (Sft_Cts)
90-101 F12.9 10-3ct/s RCS ? The number of X-ray photon counts per
second in soft band 0.3-1.2 keV (Sft_Rate)
103-119 F17.15 10-3ct/s e_RCS ? Mean error of RCs (ESftRate)
121-140 F20.15 ct CtM ? The total X-ray photon counts detected in
medium band 1.2-2 keV (Med_Cts)
142-152 F11.8 10-3ct/s RCM ? The number of X-ray photon counts per
second in medium band 1.2-2 keV (Med_Rate)
154-166 F13.11 10-3ct/s e_RCM ? Mean error of RCm (EMedRate)
168-187 F20.15 ct CtH ? The total X-ray photon counts detected in
hard band 2-7 keV (Hrd_Cts)
189-201 F13.9 10-3ct/s RCH ? The number of X-ray photon counts per
second in hard band 2-7 keV (Hrd_Rate)
203-219 F17.15 10-3ct/s e_RCH ? Mean error of RCh (EHrdRate)
221-241 F21.15 ct CtB ? The total X-ray photon counts detected in
broad band 0.3-7 keV (Brd_Cts)
243-254 F12.8 10-3ct/s RCB ? The number of X-ray photon counts per
second in broad band 0.3-7 keV (Brd_Rate)
256-273 F18.15 10-3ct/s e_RCB ? Mean error of RCb (EBrdRate)
275-292 F18.15 --- HR1 Hardness ratio defined as RCm-RCs/RCm+RCs
(HR1) (2)
294-310 F17.15 --- e_HR1 Propagated error of HR1 (E_HR1)
312-329 F18.15 --- HR2 Hardness ratio defined as RCh-RCm/RCh+RCm
(HR2) (2)
331-347 F17.15 --- e_HR2 Propagated error of HR2 (E_HR2)
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Note (1): As explicited in the section 2.3 X-ray data and analysis, each
uncertainty is the addition in quadrature of the statistical and
systematic contributions and represents error radii in both RAdeg and
DEdeg.
Note (2): Hardness ratios are listed only for sources with broad band counts
greater than 10 else values are 0.
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History:
From electronic version of the journal
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
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(End) Luc Trabelsi [CDS] 21-Mar-2025